Note: Descriptions are shown in the official language in which they were submitted.
STABILIZING AQUEOUS LYSINE-HC1 COMPOSITIONS
FIELD OF THE INVENTION
This invention relates to a method of stabilizing an aqueous composition of
lysine-HC1 more
specifically, where said composition is used for the on-site preparation of a
modified acid.
BACKGROUND OF THE INVENTION
In the oil & gas industry, stimulation with an acid is performed on a well to
increase or restore
production. In some instances, a well initially exhibits low permeability, and
stimulation is employed to
commence production from the reservoir. In other instances, stimulation or
remediation is used to further
encourage permeability and flow from an already existing well that has become
under-productive due to
scaling issues or formation depletion. Acidizing is a type of stimulation
treatment which is performed above
or below the reservoir fracture pressure in an effort to initiate, restore or
increase the natural permeability
of the reservoir. Acidizing is achieved by pumping acid, predominantly
hydrochloric acid, into the well to
dissolve typically limestone, dolomite and calcite cement between the acid
insoluble sediment grains of the
reservoir rocks or to treat scale accumulation. There are three major types of
acid applications: matrix
acidizing, fracture acidizing, and breakdown acidizing (pumped prior to a
fracturing pad or cement
operation in order to assist with formation breakdown (reduce fracture
pressures, increased feed rates), as
well as clean up left over cement in the well bore or perforations. A matrix
acid treatment is performed
when acid is pumped into the well and into the pores of the reservoir
formation below the fracture pressure.
In this form of acidization, the acids dissolve the sediments formation and/or
mud solids that are inhibiting
the permeability of the rock, enlarging the natural pores of the reservoir
(wormholing) and stimulating the
flow of hydrocarbons to the wellbore for recovery. While matrix acidizing is
done at a low enough pressure
to keep from fracturing the reservoir rock, fracture acidizing involves
pumping acid into the well at a very
high pressure, physically fracturing the reservoir rock and etching the
permeability inhibitive sediments.
This type of acid treatment forms channels or fractures through which the
hydrocarbons can flow, in
addition to forming a series of wormholes. In some instances, a proppant is
introduced into the fluid which
assists in propping open the fractures, further enhancing the flow of
hydrocarbons into the wellbore. There
are many different mineral and organic acids used to perform an acid treatment
on wells. The most common
type of acid employed on wells to stimulate production is hydrochloric acid
(HCI), which is useful in
stimulating carbonate reservoirs. Some of the major challenges faced in the
oil & gas industry from using
hydrochloric acid include the following: extremely high levels of corrosion
(which is countered by the
addition of 'filming' type corrosion inhibitors that are typically themselves
toxic and harmful to humans,
the environment and equipment) reactions between acids and various types of
metals can vary greatly but
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softer metals, such as aluminum and magnesium, are very susceptible to major
effects causing immediate
damage. Hydrochloric acid produces hydrogen chloride gas which is toxic
(potentially fatal) and corrosive
to skin, eyes and metals. At levels above 50 ppm (parts per million) it can be
Immediately Dangerous to
Life and Health (IDHL). At levels from 1300-2000 ppm death can occur in 2-3
minutes. The inherent
environmental effects (organic sterility, poisoning of wildlife etc.) of acids
in the event of an unintended or
accidental release on surface or downhole into water aquifers or other sources
of water are devastating and
can cause significant pH reduction of such and can substantially increase the
toxicity and could potentially
cause a mass culling of aquatic species and potential poisoning of humans or
livestock and wildlife exposed
to/or drinking the water. An unintended release at surface can also cause
hydrogen chloride gas to be
released, potentially endangering human and animal health. This is a common
event at large storage sites
when tanks split or leak. Typically if near the public, large areas need to be
evacuated post event and a
comprehensive, expensive to implement, emergency evacuation plan needs to be
in place prior to approval
of such storage areas. Because of its acidic nature, hydrogen chloride gas is
also corrosive, particularly in
the presence of moisture. The inability for mineral acids with common
corrosion control additives and
blends of such to biodegrade naturally results in expensive cleanup-
reclamation costs for the operator
should an unintended release occur. Moreover, the toxic fumes produced by
mineral & some organic acids
are harmful to humans/animals and are highly corrosive and/or produce
potentially explosive vapours.
Transportation and storage requirements for acids are restrictive and taxing.
As well, the dangers
surrounding exposure by personnel handling the blending of such dangerous
products constrict their
use/implementation in areas of high risk such as within city limits and
environmentally sensitive areas such
as offshore.
Another concern is the potential for exposure incidents on locations due to
high corrosion levels,
even at ambient temperatures, of acids causing potential storage tank failures
and/or deployment equipment
failures i.e. coiled tubing or high pressure iron failures caused by high
corrosion high rates (pitting, cracks,
pinholes and major failures). Other concerns include: downhole equipment
failures from corrosion causing
the operator to have to execute a work-over and replace down hole pumps,
tubulars, cables, packers etc.;
inconsistent strength or quality level of mineral & organic acids; potential
supply issues based on industrial
output levels; high levels of corrosion on surface pumping equipment resulting
in expensive repair and
maintenance levels for operators and service companies; the requirement of
specialized equipment that is
purpose built to pump acids greatly increasing the capital expenditures of
operators and service companies;
and the inability to source a finished product locally or very near its end
use; transportation and onsite
storage difficulties. Typically, acids are produced in industrial areas of
countries located some distance
from oil & gas producing areas, up to 10 additives can also be required to
control various aspects of the
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acid's properties adding to complications in the handling and shipping
logistics. Having an alternative that
requires minimal additives is very advantageous. Extremely high corrosion and
reaction rates with
temperature increase causes conventional acids to spend/react or "neutralize"
prior to achieving the desired
effect such as deeply penetrating an oil or gas formation to increase the
wormhole or etched "pathway"
effectively to allow the petroleum product to flow freely to the wellbore. As
an example, hydrochloric acid
can be utilized in an attempt to free stuck drill pipe in some situations.
Prior to getting to the required depth
to dissolve the formation that has caused the pipe/tubing to become stuck many
acids spend or neutralize
on formation closer to the surface due to increased bottom hole temperatures
and greatly increased reaction
rate, so it is advantageous to have an alternative that spends or reacts more
methodically allowing the debris
to be treated with a solution that is still active, allowing the pipe/tubing
to be pulled free. When used to
treat scaling issues on surface equipment due to water mineral precipitation,
conventional acids are exposed
to human and mechanical devices as well as expensive equipment causing
increased risk and cost for the
operator.
When mixed with bases or higher pH fluids, acids will create a large amount of
thermal energy
(exothermic reaction) causing potential safety concerns and equipment damage,
acids typically need to be
blended with fresh water (due to their intolerance of highly saline water,
causing potential precipitation of
minerals) to the desired concentration requiring companies to pre-blend off-
site as opposed to blending on-
site with sea or produced water thereby increasing costs associated with
transportation. Conventional
mineral acids used in a pH control situation can cause rapid degradation of
certain polymers/additives
requiring increased loadings or chemicals to be added to counter these
negative effects.
Many offshore areas of operations have very strict regulatory rules regarding
the
transportation/handling and deployment of acids causing increased liability
and costs for the operator.
When using an acid to pickle tubing or pipe, very careful attention must be
paid to the process due to high
levels of corrosion, as temperatures increase, the typical additives used to
control corrosion levels in acid
systems begin to degrade very quickly (due to the inhibitors "plating out" on
the steel or sheering out in
high rate applications) causing the acids to become very corrosive and
resulting in damage to downhole
equipment/tubulars. Conventional acids can be harmful to many elastomers
and/or seals found in the oil &
gas industry such as those found in blow out preventers (BOP's) /downhole
tools/packers/submersible
pumps/seals etc. Having to deal with spent acid during the flowback process is
also very expensive as these
acids typically are still at a low pH and remain toxic and corrosive. It is
advantageous to have an acid blend
that can be exported to production facilities through pipelines that, once
spent or applied, is much higher
than that of spent HC1, reducing disposal costs/fees. Also, mineral acids will
typically precipitate iron
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Date Recue/Date Received 2022-01-21
and/or minerals solubilized during the operation as the pH of the spent acid
increases causing facility upsets
and lost production. It is advantageous to have a strong acid that will hold
these solubilized minerals and
metals in solution even as pH rises dramatically close to a neutral state,
greatly reducing the need to dispose
of spent acids and allowing them to be processed and treated in a more
economical manner. Acids are used
in the performance of many operations in the oil & gas industry and are
considered necessary to achieve
the desired production of various petroleum wells and associated equipment,
maintain their respective
systems and aid in certain drilling operational functions (i.e. freeing stuck
pipe, filter cake treatments). The
associated dangers that come with using mineral acids are expansive and
tasking to mitigate through
controls whether they are chemically or mechanically engineered. Eliminating
or even simply reducing the
negative effects of strong acids while maintaining their usefulness is a
struggle and risk for the industry. As
the public and government demand for the use of less hazardous products
increases, companies are looking
for alternatives that perform the required ffinction without all or most of
the drawbacks associated with the
use of conventional acids.
Several operations in the oil industry expose fluids to very high temperatures
(some up to and over
200 C / 392 F), the compositions used in these various operations need to
withstand high temperatures
without losing their overall effectiveness. These compositions must also be
capable of being applied in
operations over a wide range of temperatures while not or at least minimally
affecting or corroding the
equipment with which it comes in contact in comparison to a conventional
mineral acid of which the
corrosion effect at ultra-high temperatures is very difficult and expensive to
control. Offshore oil and gas
operations are highly regulated due to the environmental concerns which arise
from their operations and
the potential for spills along with confined work spaces offering little
chance of egress in the case of an
incident. The complexity of drilling and completing offshore wells is always
compounded by both safety
issues (exposure to dangerous chemicals as an example) for workers on such
offshore oil rigs and
production platforms as well as environmental concerns. Many countries
bordering the waters where
offshore drilling and production is routinely carried out have put into play a
number of regulations and
operational parameters aimed at minimizing the environmental and human
exposure impact. These
regulations/procedures include the ban and/or regulation of certain chemicals
which may be harmful to
marine life and/or the environment. In order to overcome these very
restrictive regulations, many oil
companies employ very costly containment programs for the handling of certain
chemicals, such as acids,
which have a wide array of uses in the industry of oil and gas exploration and
production. Many of the
issues related with offshore oil and gas exploration and production stem from
the fact that the conditions
under which this is carried out are substantially different than those
encountered in the same types of
operations carried out onshore, including but not limited to confined spaces,
lack of escape routes, very
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Date Recue/Date Received 2022-01-21
expensive down hole and surface safety and operational equipment compared to
onshore requirements
Acids conventionally used in various oil and gas operations can be exposed to
temperatures in excess of
200 C. At these temperatures, their reactivity and corrosive properties is
exponentially increased and as
such their economical effectiveness is greatly decreased. Corrosion is one of
the major concerns at high
temperatures and is difficult and expensive to control with additional
chemistry, if it can be controlled at
all. In many situations a mechanical procedure must be utilized as opposed to
a chemical solution due to
temperature constraints modified and synthetic acids developed and currently
patented such as those
containing main components of urea and hydrochloric acid are aimed at
increasing personnel safety,
reducing corrosion effects, slowing down the reaction rate and reducing the
toxicity of HC1. However, it
has been found that at temperatures above 90 C the urea component in a
synthetic or modified acid
containing such compound tends to ultimately decompose and produce ammonia and
carbon dioxide as a
by-product of decomposition. The ammonia component will neutralize the acidic
component or HC1 and
render the product non-reactive or neutral. Additionally there is the risk of
wellbore and/or formation
damage due to uncontrolled solubilized mineral precipitation due to the
increase in pH caused
predominantly by the formation of ammonia during the decomposition phase.
CA patent application 2,865,855 discloses compositions comprising hydrochloric
acid at a
concentration between 8 wt% and 28 wt% inclusive and at least one amino acid.
The amino
acid/hydrochloric acid molar ratio is between 0.2 and 1.5, and sufficient
water is present to dissolve the
hydrochloric acid and the amino acid. The amino acid may comprise alanine,
asparagine, aspartic acid,
cysteine, glutamic acid, histidine, leucine, lysine, methonine, proline,
serine, threonine or valine or
combinations thereof.
US patent application US 20140041690 Al teaches the use of glycine in the
making of a synthetic
acid that is said to obviate all the drawbacks of strong acids such as
hydrochloric acid. The new compound
is made by dissolving glycine in water, in a weight ratio of approximately 1:1
to 1:1.5. The description
states that the solution is mixed until the glycine is essentially fully
dissolved in the water. Once dissolution
is complete, hydrogen chloride gas is dissolved in the solution to produce the
new compound, which is
referred to as hydrogen glycine. Despite the prior art and in light of the
substantial problems elicited by the
use of acids in oil and gas operations at high temperatures, there still
exists a critical need to find an
alternative to known synthetic or complexed/modified acids which will remain
stable above temperatures
of 90 C while still providing the safety and lower corrosion effects of a
modified acid while maintaining
strength/performance of a hydrochloric acid. The inventors have surprisingly
and unexpectedly found that
by combining an amino acid with hydrochloric acid in appropriate ratios one
can obtain both a safer
Date Recue/Date Received 2022-01-21
alternative to HC1 all the while maintaining the original performance
properties of hydrochloric acid and
its usefulness in oil and gas operations. It was discovered that preferred
compositions of the present
invention exhibit stability for operations at elevated temperature (above 90 C
and, in some cases, up to
220 C) them useful in the oil and gas industry for all applications where an
acid is required and provides
operators the ability to treat high and ultra-high temperature completions and
maintenance/production
operations with a technology that provides a level of safety, technical
advantages and low corrosion
unavailable in industry until now. Preferred compositions according to the
present invention can ideally be
used in various oilfield operations, including but not limited to: spearhead
breakdown acid, acid fracturing
operations, injection-disposal well treatments, high temperature cyclical
steam injection (CSS) scale
treatments, steam assisted gravity drainage (SAGD) scale treatments, surface
and subsurface equipment
and pipelines facilities, filter cake removal, tubing pickling, matrix
acidizing operations, stimulations,
fracturing, soaks, cement squeezes, fluid pH control, stuck pipe operations,
and coiled tubing acid washes,
soaks and squeezes.
CA patent 2,974,757C discloses an aqueous synthetic acid composition for use
in oil industry
activities, said composition comprising: lysine and hydrogen chloride in a
molar ratio ranging from 1:3 to
1:12.5, preferably from more than 1:5 to 1:8.5; it can also further comprise a
metal iodide or iodate; an
alcohol or derivative thereof. Said composition demonstrates advantageous
properties over known synthetic
acids at temperatures above 90 C. It is stated that preferred compositions can
be used for various oil and
gas industry operations. It is also stated that preferred embodiments of said
composition providing
substantial advantages in matrix acidizing by increasing the effectiveness of
wormholing compared to
conventional mineral acids such as HC1.
It has been discovered since the introduction of a modified acid comprising
lysine and HC1 in a
molar ratio ranging from 1:3 to 1:12.5 that, during the shipping of the
components in two separate tanks in
the hull of a ship (a solution of liquid lysine monohydrochloride in the water
tank of a ship and commercial
grade HC1 in the acid tank of a ship), there were signs that, under some
conditions, the lysine
monohydrochloride solution would recrystallize in the tank prior to being
blended with the commercial
grade HC1. This undermines the value of the modified acid comprising lysine
and HC1 if such cannot be
reliably shipped to remote location or even to offshore. In order to maximize
the volume of modified acid
which is being transported by ship, it is desirable that the two components of
the modified acid be shipped
in separate components. Since there is an acid tank and a water tank on ships
capable of transporting acids,
and that modified acids cannot be shipped in the water tank, it is thus
necessary to optimize the cargo by
shipping the acid in the acid tank and the lysine monohydrochloride in an
aqueous solution in the water
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Date Recue/Date Received 2022-01-21
tank of the ship. The lysine monohydrochloride aqueous composition is
typically a saturated composition
so as to maximize the volume shipped. However, such a saturated composition is
metastable and is prone
to re-crystallization at temperatures as low as 18 C. This results in an
inability to use the lysine
monohydrochloride (as a saturated solution of approximately 50 wt.% content)
until the contents have been
re-dissolved, which leads to substantial delays, especially when ships need to
be off-loaded quickly.
In light of this drawback, there is a need to develop a method to stabilize
compositions of lysine
monohydrochloride to be shipped in the water tanks of ships. The value of
modified acid compositions
comprising lysine monohydrochloride has been recently established, hence a
method to overcome the
above-mentioned drawback would help enhance its reliability and value as a
replacement of conventional
hydrochloric acid.
SUMMARY OF THE INVENTION
According to an aspect of the present invention, there is provided a method to
improve and/or
ensure the stability of an aqueous composition comprising an amino acid salt
such as lysine
monohydrochloride where such a composition is typically saturated or even in a
supersaturated state.
According to a preferred embodiment of the present invention, said aqueous
composition comprising lysine
and HC1 is used as a premix in the preparation of a modified acid composition
lysine & hydrogen chloride
in a molar ratio ranging from 1:2.1 to 1:12.5; preferably, the aqueous
synthetic acid composition comprises
lysine and hydrogen chloride in a molar ratio ranging from 1:3 to 1:12.5;
preferably in a molar ratio ranging
from 1:3.5 to 1:9, more preferably in a molar ratio ranging from 1:4.5 to
1:8.5, even more preferably in a
molar ratio ranging from more than 1:5 to 1:6.5.
It has been surprisingly and unexpectedly discovered that by adding a first
acidic component to a
saturated or supersaturated aqueous composition comprising an amino acid salt
selected from the group
consisting of: lysine monohydrochloride, glycine HC1; histidine HC1, arginine
HC1, asparagine HC1; and
glutamine HC1, one can improve the stability of the composition. According to
a preferred embodiment of
the present invention, the salts to use are selected from the group consisting
of: lysine monohydrochloride,
and glycine HC1. The most preferred salt to use is lysine monohydrochloride.
Combining a premix
composition comprising water, said amino acid salt and said first acidic
component with a commercial
grade acid such as hydrochloric acid, leads to the generation of a
reconstituted modified acid composition.
Reconstituted modified acid compositions according to the present invention
have been developed
for the oil & gas industry and its associated applications, by targeting the
problems of corrosion, logistics
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Date Recue/Date Received 2022-01-21
& handling, human & environmental exposure, reaction rates, toxicity levels,
biodegradation tendencies
and formation/fluid compatibilities and facility and/or production and water
treatment infrastructure
compatibilities. It is an object of the present invention to provide an
aqueous synthetic acid composition
which can be used over a broad range of applications in the oil and gas
industry and which exhibit
advantageous properties over known compositions.
According to a preferred embodiment of the present invention, there is
provided a process to
stabilize a saturated or supersaturated aqueous lysine monohydrochloride when
such is exposed to
temperatures below 7 C. It was noted that aqueous solutions of lysine
monohydrochloride (as a premix
for the preparation of a modified acid comprising HC1 and lysine) are shipped
to destination (in the water
tank of a ship) prior to mixing this premix with commercial grade Hydrochloric
acid (such as but not
limited to 32 % Hydrochloric acid, 37 % Hydrochloric acid) would sometimes
exhibit some issues of
stability. The inventors have surprisingly discovered that by adding up to 1 %
Hydrochloric acid into a
saturated or near saturated lysine monohydrochloride aqueous solution, the
stability of the lysine
monohydrochloride could be enhance the stability of such a solution so that
the lysine monohydrochloride
would not recrystallize out of solution during the time it was exposed to
conditions (such as temperatures
below 18 C) which can typically cause the recrystallization of the lysine
monohydrochloride.
According to a preferred embodiment of the present invention, there is
provided a method to
maintain stable a lysine monohydrochloride solution (especially during
shipping or long term storage) prior
to its combination in a vessel or on the fly with hydrochloric acid to provide
a reconstituted modified acid
composition for use in oil and gas activities, said composition comprising: -
lysine & hydrogen chloride in
a molar ratio ranging from 1:2.1 to 1:12.5; preferably, the aqueous synthetic
acid composition comprises
lysine and hydrogen chloride in a molar ratio ranging from 1:3 to 1:12.5;
preferably in a molar ratio ranging
from 1:3.5 to 1:9, more preferably in a molar ratio ranging from 1:4.5 to
1:8.5, even more preferably in a
molar ratio ranging from more than 1:5 to 1:6.5.
According to an aspect of the present invention, there is provided a method to
increase the stability
of an aqueous composition comprising lysine monohydrochloride, said process
comprising the steps of:
- providing a vessel;
- adding a pre-determined amount of water into said vessel;
- adding a pre-determined amount of an acid to said water; and
- adding lysine monohydrochloride to said vessel; and
- mixing the blend until said lysine monohydrochloride is fully
dissolved;
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Date Recue/Date Received 2022-01-21
wherein the resulting aqueous composition of lysine monohydrochloride having a
pH of no less than 2.5-
3, is stable down to a temperature of 5 C and said composition comprising
lysine and HC1 in a molar ratio
containing an excess of acid of up to 5 vol. %. Preferably, the composition is
stable down to a temperature
of 7.5 C. Also preferably, the composition is stable down to a temperature of
10 C.
According to a preferred embodiment of the present invention, the acid is
selected from the group
consisting of: organic acids; mineral acids; and combinations thereof.
Preferably, the organic acid is
selected from the group consisting of: citric acid; acetic acid;
methanesulfonic acid; and oxalic acid.
Preferably, the mineral acid is selected from the group consisting of:
hydrochloric acid; nitric acid; sulfuric
acid; etc. More preferably, the mineral acid is hydrochloric acid.
According to an aspect of the present invention, there is provided a
stabilized aqueous composition
of lysine monohydrochloride wherein said composition consists of:
- lysine-monohydrochloride in an amount ranging from 35 wt. % to 45 wt. %;
- water; and
- an acidic component adapted to stabilize said lysine monohydrochloride;
wherein said composition has a pH of no less than 2.5-3.0 and is stable down
to a temperature of 5 C,
wherein stable is meant to understand that the lysine-monohydrochloride does
not re-crystallize out from
the composition.
According to a preferred embodiment of the present invention, said lysine-
monohydrochloride is
present in an amount ranging from 37.5 wt. % to 45 wt. %. More preferably,
said lysine-monohydrochloride
is present in an amount ranging from 40 wt. % to 45 wt. %.
According to an aspect of the present invention, there is provided a method to
increase the stability
of an aqueous composition comprising an amino acid salt, said process
comprising the steps of:
- providing a saturated aqueous composition of an amino acid salt
selected from the
group consisting of: lysine monohydrochloride, glycine HC1; histidine HC1,
arginine
HC1, asparagine HC1; and glutamine HC1;
- adding an amount of acid to said aqueous composition of amino
acid salt to decrease
the pH of such composition to a pH of no less than 2.5-3, resulting in a
stabilized
composition comprising said amino acid containing an excess of acid of up to 5
vol.
A.
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Date Recue/Date Received 2022-01-21
According to an aspect of the present invention, there is provided a method to
increase the stability
of an aqueous composition comprising an amino acid salt, said process
comprising the steps of:
- providing a vessel;
- adding a pre-determined amount of water into said vessel;
- adding a pre-determined amount of an acid to said water;
- adding said amino acid salt to said vessel; and
- mixing the blend until said amino acid salt is fully dissolved;
wherein the resulting aqueous composition of amino acid salt having a pH of no
less than 2.5-3, is stable at
down to a temperature of 5 C and said composition comprising lysine and HC1 in
a molar ratio containing
an excess of acid of up to 5 vol. %. Preferably, the composition is stable
down to a temperature of 7.5 C.
Also preferably, the composition is stable down to a temperature of 10 C.
According to a preferred embodiment of the present invention, said amino acid
salt is selected from
the group consisting of: lysine monohydrochloride, glycine HC1; histidine HC1,
arginine HC1, asparagine
HC1; and glutamine HC1. Preferably, said amino acid is selected from the group
consisting of: lysine
monohydrochloride, and glycine HC1.
According to an aspect of the present invention, there is provided a
reconstituted lysine-HC1-
containing modified acid composition for use in the oil industry to perform an
activity selected from the
group consisting of: stimulate formations; assist in reducing breakdown
pressures during downhole
pumping operations; treat wellbore filter cake post drilling operations;
assist in freeing stuck pipe; descale
pipelines and/or production wells; increase injectivity of injection wells;
lower the pH of a fluid; remove
undesirable scale on a surface selected from the group consisting of:
equipment, wells and related
equipment and facilities; fracture wells; complete matrix stimulations;
conduct annular and bullhead
squeezes & soaks; pickle tubing, pipe and/or coiled tubing; increase effective
permeability of formations;
reduce or remove wellbore damage; clean perforations; and solubilize
limestone, dolomite, calcite and
combinations thereof; said composition comprising lysine and HC1 in a molar
ratio ranging from 1:2.1 to
1:12.5. Preferably, said the composition comprises lysine and HC1 in a molar
ratio ranging from 1:4.5 to
1:8.5.
According to an aspect of the present invention, there is provided a use of a
stabilized aqueous
composition of lysine monohydrochloride for the preparation of a modified acid
composition, wherein said
stabilized aqueous composition of lysine monohydrochloride consists of:
- lysine-monohydrochloride in an amount ranging from 35 wt. % to 45 wt. %;
Date Recue/Date Received 2022-01-21
- water; and
- an acidic component adapted to stabilize said lysine monohydrochloride;
wherein said stabilized aqueous composition has a pH of no less than 2.5-3.0
and is stable down to a
temperature of 5 C, wherein stable is meant to understand that the lysine-
monohydrochloride does not re-
crystallize out from the composition; and
wherein said modified acid composition has a pH below 1 and comprises lysine
and HC1 in a molar ratio
ranging from 1:2.1 to 1:12.5.
According to an aspect of the present invention, there is provided a use of a
stabilized aqueous
composition of an amino acid salt for the preparation of a modified acid
composition, wherein said
stabilized aqueous composition of lysine monohydrochloride consists of:
- an amino acid salt in an amount ranging from 35 wt. % to 45 wt. %;
- water; and
- an acidic component adapted to stabilize said amino acid salt;
wherein said stabilized aqueous composition has a pH of no less than 2.5-3.0
and is stable down to a
temperature of 5 C, wherein stable is meant to understand that the amino acid
salt does not re-crystallize
out from the composition; and
wherein said modified acid composition has a pH below 1 and comprises said
amino acid and HC1 in a
molar ratio ranging from 1:2.1 to 1:12.5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The description that follows, and the embodiments described therein, is
provided by way of
illustration of an example, or examples, of particular embodiments of the
principles of the present invention.
These examples are provided for the purposes of explanation, and not
limitation, of those principles and of
the invention.
Lysine-HC1 is the main component in terms of volume and weight percent of the
aqueous acid
composition upon blending of commercial grade Hydrochloric acid and lysine
monohydrochloride, and as
an amino acid it contains at least one amino group, -NH2, and one carboxyl
group, -COOH. When added
to hydrochloric acid a Lewis acid/base adduct is formed where the primary
amino group acts as a Lewis
base and the proton of the Hydrochloric acid as Lewis acid. The formed adduct
greatly reduces the
hazardous effects of the hydrochloric acid on its own, such as the fuming
effect, the hygroscopicity, and
the highly corrosive nature The excess nitrogen can also act as a corrosion
inhibitor at higher temperatures.
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Date Recue/Date Received 2022-01-21
Lysine & hydrogen chloride are present in a molar ratio ranging from 1:3 to
1:12.5; preferably in a molar
ratio ranging from 1:4.5 to 1:9, and more preferably in a molar ratio ranging
from more than 1:5 to 1:8.5.
Lysine monohydrochloride can be purchased as a white powder. It has a pH
ranging from 5.0-6 at
91.3g/1 at 25 C (77 F); melting point/range: 263 C (505 F); it has a
density of 1.28 g/cm3 at 20 C (68
F); and can dissolve 91.3 g/1 of water at 20 C (68 F).
Example #1: Composition of Lysine-HC1 premix according to a preferred
embodiment of the
present invention
Various premixes containing lysine monohydrochloride according to preferred
embodiment so the
present invention were prepared according to the following process. According
to a preferred embodiment
of the present invention, the process comprises the following steps:
1. add the water amount as listed in Table 1 or 2 into the vessel
(reactor);
2. start reactor circulation (note: the next step is highly exothermic;
fumes can be evolved
during this process. The usage of a water scrubber is recommended);
4. slowly add the required volume of hydrochloric acid according to Table 1
into the reactor;
5. in a controlled manner, slowly introduce lysine monohydrochloride into
the reactor (note:
if lysine monohydrochloride is added too rapidly, formation of large solid
masses can occur which can plug
equipment and solubilize slowly due to the reduced available surface area);
6. circulate until complete mixing has occurred (at least one complete
volume turnover) (note:
flush fluid lines with water to prevent lysine from crystallizing in the
tubing or pumps).
The resulting premix can then be shipped to the destination where it is
intended to be used in the
preparation of a reconstituted modified acid composition.
Table 1:
Volume of Products Required to make 1000L (1125 kg) of Premix #1, #2 and #3
Premix #1 Premix #2 Premix #3
Premix #4
(contains 10% (contains 7% dilution (contains 5% dilution
(reduced
dilution water) water) water)
Hydrochloric acid
conc. 0.33%)
Hydrochloric Acid 31 kg (27 1) 32 kg (28 1) 33 kg (29 1) 11 kg (10
1)
(32%)
Water 655 kg (656 1) 628 kg (629 1) 608 kg (6101) 665 kg
(666 1)
Lysine 439 kg 464 kg 483 kg 448 kg
monohydrochloride
12
Date Recue/Date Received 2022-01-21
Table 2: Weight
of Products Required to make 889 1 (1000 kg) of Premix #1, #2 and #3
Premix #1 Premix #2 Premix #3
Premix #4
(contains 10% (contains 7% dilution (contains 5% dilution
(reduced
dilution water) water) water)
Hydrochloric acid
conc. 0.33%)
Hydrochloric Acid 27 kg 29 kg 30 kg 10
kg (9 1)
(32 %) (24 L) (25 L) (26 L)
Water 583 kg 558 kg 541 kg 591 kg (592
1)
(584 L) (559 L) (542 L)
Lysine 399 kg
monohydrochloride 390 kg 413 kg 429 kg
Premixes #1, #2 and #3 have a hydrochloric acid content of approximately 0.925
%, while the
premix #4 has a lower hydrochloric acid content of approximately 0.33 wt. %.
The composition labelled
Premix #2 was used in further testing. The density of said premix #2 was
measured to be 1.144 kg/m' while
the pH @ ambient temperature was determined to be 2.75. Premix #4 has a pH of
approximately 3Ø
According to a preferred embodiment of the present invention, it is possible
to adjust the lysine-
HC1 ratio in the reconstituted lysine-HC1-containing modified acid composition
depending on the intended
application and the desired solubilizing ability. By increasing the ratio of
the HC1 component, the
solubilizing ability will increase while still providing certain health,
safety, environmental and operational
advantages over hydrochloric acid. It is preferable to add the lysine at a
molar ratio less than 1:1 to the
moles of Hydrochloric acid (or any acid). Tests have shown than even adding
lysine to HC1 in a molar
ratio of around 1:2 would neutralize the hydrochloric acid to the point of
almost completely removing all
of its acidic character. Preferably, the composition according to the present
invention comprises at most 1
mole of lysine per 3.0 moles of HC1. The lysine-hydrochloride also allows for
a reduced rate of reaction
when in the presence of carbonate-based materials. This again is due to the
stronger molecular bonds
associated over what hydrochloric acid traditionally displays. Further, since
the composition according to
the present invention is mainly comprised of lysine (which is naturally
biodegradable), the product testing
has shown that the lysine hydrochloride will maintain the same
biodegradability function, something that
hydrochloric acid will not on its own. Alcohols and derivatives thereof, such
as alkyne alcohols and
derivatives and preferably propargyl alcohol and derivatives thereof can be
used as corrosion inhibitors.
For offshore uses, to make a modified acid comprising lysine and HC1 in a
molar ratio ranging from
1:3 to 1:12.5; preferably in a molar ratio ranging from 1:4.5 to 1:9, and more
preferably in a molar ratio
13
Date Recue/Date Received 2022-01-21
ranging from more than 1:5 to 1:8.5, the HC1 is transported in an acid-
resistant tank inside a ship and the
lysine-HC1 (1:1 molar ratio) is transported in the water tank portion of the
vessel. Once arrived on site, the
two portions (HC1 and lysine-HC1 (in a 1:1 molar ratio) are blended to the
desired ratio of HCI:lysine.
According to a preferred embodiment the modified acid can be blended in
batches or on the fly.
Currently, to transport a modified acid comprising lysine and HC1 in a molar
ratio ranging from 1:3
to 1:12.5 one can only use the acid tank portion of a ship. This means that
basically half of the ship's
potential storage room is left unused. To overcome this logistical barrier,
the inventors have developed a
safe pre-mix to be combined with commercial grade acids such as Hydrochloric
acid , said pre-Omix are
intended on being shipped inside the water tank (previously mentioned) where
the pH and other
characteristics are suitable and safe and non-corrosive for the water tank for
extended exposure durations
of time (such as several weeks).
Typically, ship tanks which are used to carry chemicals are coated with acid-
resistant coatings.
One widely used type of coating is epoxy-based. Appropriate epoxy-cased
coatings will protect both the
steel of the from being affected by the contents and the contents from being
contaminated. One such epoxy
-based coating used for such purpose is Hempadur 35760. This coating provides
very high corrosion
protection properties and excellent chemical resistance and, is especially
well-suited for new and old storage
tanks containing oils, fuels, bio fuels and a wide range of chemicals. Another
epoxy-based coating is
Hempadur 85671, an epoxy phenolic resistant to very aggressive cargos, such
as acids.
Another type of coating is Intershield 300HS which is described as a high
solids, abrasion
resistant, aluminum pure epoxy coating capable of providing excellent long
term anti-corrosive protection
and low temperature capability. It comes as a universal primer which can be
applied directly to
mechanically prepared shop primer or suitably prepared bare steel.
Compatibility testing of Premix #2 on coupons coated in Intershield 300HS and
Hempadur
85671 epoxy was carried out in order to determine the feasibility of
transporting acidic precursor (premixes
as discussed above) compositions comprising lysine monohydrochloride and an
excess of acid component
where the pH is above 2.5. Once the acidic precursor compositions reaches its
destination, according to a
preferred embodiment of the present invention, an operator may blend such
composition with commercial
grade Hydrochloric acid on-the-fly or in batches depending on the situation.
According to a preferred
embodiment of the present invention such blending is intended on yielding a
composition comprising a
lysine and HC1 in a molar ratio ranging from 1:3 to 1:12.5; preferably in a
molar ratio ranging from 1:4.5
14
Date Recue/Date Received 2022-01-21
to 1:9, and more preferably in a molar ratio ranging from more than 1:5 to
1:8.5. Preferably, the
composition comprises lysine and HC1 in a molar ratio ranging from 1:4.5 to
1:8.5.
Compatibility testing
The tests were executed on 316 stainless steel coupons coated in Intershield
300HS and
Hempadur 85671 epoxy submerged in Premix #2 blend at ambient temperature and
55 C (131 F), for 7
and 14 days. After the test period, the integrity of the epoxy resin was
observed to not be compromised.
Compatibility testing between Premix #2 and the Intershield 300HS epoxy
coated coupons had shown
minimal mass change of < 0.12 % and the Hempadur 85671 epoxy coated coupons
had shown minimal
mass change of < 0.15 % after 14 days. Full testing results are reported in
Tables 3 and 4.
Compatibility Testing with Intershield 300HS Epoxy Coated Coupons
Procedure:
To prepare the coupons for corrosion testing, the Intershield 300HS epoxy was
prepared by mixing
2.5 parts of A with 1 part of B as per manufacturers specifications. The 316SS
coupons were then coated
in the epoxy and hung to allow excess to drip off. The coupons were then
placed into an oven at 45 C
(113 F) for 1 hour and then removed to apply a second layer of epoxy coat to
cover any areas that may
have had a thin layer or exposed corners. The coupon was then hung to dry
overnight in an oven set to 45
C (113 F) before the coupons were weighed. A photo of each coupon was taken
to document the initial
appearance of the surface.
Procedure:
To determine the corrosion properties of Premix #2, the blend was evaluated at
ambient
temperature, approximately 20 C (68 F) and at 50 C (122 F) on the epoxy
coated coupons. At ambient
temperature, the tests were executed on a bench top, while at 50 C (122 F),
tests were executed in a heated
water bath. After the exposure time, the coupons were removed, washed with
warm water and soap, iso-
propanol, and dried. The weights of the coated coupons were recorded. A photo
of each coupon was taken
to document the appearance of the surface after the exposure to the Premix #2.
Table 3: Corrosion results of Premix #2 with Intershield 300HS epoxy
coated coupons
Duration Temperature Weight change
(days)
( C) ( F) grams Wt %
Premix #2 7 20 68 +0.0059 + 0.03
Date Recue/Date Received 2022-01-21
Premix #2 7 50 122 +0.0157 + 0.09
Premix #2 14 20 68 -0.0006 - 0.00
Premix #2 14 50 122 -0.0227 -0.13
15% Hydrochloric acid 7 20 68 +0.0284 + 0.16
15% Hydrochloric acid 7 50 122 +0.1018 + 0.57
15% Hydrochloric acid 14 20 68 +0.0560 +0.31
15% Hydrochloric acid 14 50 122 +0.1616 +0.93
Compatibility Testing with Hempadur 85671 Epoxy Coated Coupons
Procedure:
To prepare the coupons for corrosion testing, the Hempadur 85671 epoxy was
prepared by mixing
8.9 parts of A with 1.1 parts of B as per manufacturers specifications. The
316SS coupons were then coated
in the epoxy and hung to allow excess to drip off. The coupons were then
placed into an oven at 45 C
(113 F) for 1 hour and then removed to apply a second layer of epoxy coat to
cover any areas that may
have had a thin layer or exposed corners. The coupon was then hung to dry
overnight in an oven set to
45 C (113 F) before the coupons were weighed. A photo of each coupon was taken
to document the initial
appearance of the surface.
Procedure:
To determine the corrosion properties of Premix #2# the blend was evaluated at
ambient
temperature, approximately 20 C (68 F) and at 55 C (131 F) on the epoxy
coated coupons. At ambient
temperature, the tests were executed on a bench top, while at 55 C (131 F),
tests were executed in a heated
water bath. After the exposure time, the coupons were removed, washed with
warm water and soap, iso-
propanol, and dried. The weights of the coated coupons were recorded. A photo
of each coupon was taken
to document the appearance of the surface after the exposure to the Premix #2.
Results:
Test results of the compatibility experiment with Hempadur 8567 lepoxy coated
coupons are
shown in Table 2.
Table 4:
Corrosion results of Premix #2 with Hempadur 85671ep0xy coated coupons
Duration Temperature Weight change
(days)
16
Date Recue/Date Received 2022-01-21
( C) ( F) grams Wt %
Premix #2 7 20 68 +0.0149 +0.09
Premix #2 7 55 131 +0.0226 +0.13
Premix #2 14 20 68 +0.0130 +0.08
Premix #2 14 55 131 +0.0116 +0.07
15% Hydrochloric acid 7 20 68 +0.0207 + 0.12
15% Hydrochloric acid 7 55 131 +0.0616 +0.37
15% Hydrochloric acid 14 20 68 +0.0331 +0.20
15% Hydrochloric acid 14 55 131 +0.0931 +0.54
Stability Testing
1. Summary
Compatibility and stability testing was performed utilizing Premix #2 at
various temperatures to
determine fluid stability. Stability testing was performed at 5 C (41 F) and
50 C (122 F) over 14 days,
after which the jar was removed and observed for any solids. Stability testing
indicated no observable
solids in the sample container after 14 days at 5 C (41 F) and 50 C (122 F).
Procedure:
A glass jar containing Premix #2 was placed into a water bath at 5 C (41 F),
another sample was
placed in a water bath at 50 C (122 F). Both samples were tested for 14
days, then observed for blend
stability.
Photographs of the blends were taken before and after the exposure period.
Upon review of the
photos taken before and after exposure, no observable incompatibility or
solids could be observed after 14
days at 5 C (41 F) or 50 C (122 F). The testing carried out above supports
the approach set out according
to a preferred embodiment of the present invention, to enhance the stability
of saturated or supersaturated
aqueous lysine monohydrochloride compositions for transport. Photographs of
the coupons were also taken
before and after exposure so as to document the appearance of the surface
before and after exposure to the
compositions described herein.
Example 2: Preparation of batch of a reconstituted modified acid comprising
a 1:2.1 molar ratio
of lysine to HC1
17
Date Recue/Date Received 2022-01-21
Lysine mono-hydrochloride is used as starting reagent. To obtain a 1:2.1 molar
ratio of lysine to
HC1, 370 ml of a 50 wt.% lysine-HC1 (also referred to as a premix) solution
and 100 ml HC1 aq. 36% (22
Baume) are combined. In the event that additives (such as corrosion
inhibitors) are used, they are added
after thorough mixing. For example, propargyl alcohol, and potassium iodide
can be added at this point.
Circulation is maintained until all products have been solubilized. Additional
components can now be
added as required. The process to obtain other compositions of lysine-HC1 of
various molar ratios is similar
where the only difference lies in the amount of Hydrochloric acid added.
The resulting composition of Example 2 is an amber colored liquid with a
fermentation like odour
having shelf-life of greater than 1 year. It has a freezing point temperature
of approximately -30 C and a
boiling point temperature of approximately 100 C. It has a specific gravity of
1.15+/- 0.02. It is completely
soluble in water and its pH is less than 1. The composition is biodegradable
and is classified as a mild
irritant according to the classifications for skin tests. The composition is
substantially low fuming.
Example 3:
Preparation of batch of a reconstituted modified acid comprising a 1:4.5 molar
ratio
of lysine to HC1
This composition is obtained through the following mixing ratio: 370 ml of
Premix (saturated
composition of lysine monohydrochloride in water and acid) solution + 300 ml
22 Baume HC1; which leads
to the following ratio: 1 mol Lysine monohydrochloride to 4.5 mol HC1. The
composition of Example 3
has an amber liquid appearance. Its salinity is 48%. Its freezing point is
minus 45 C and boiling point
above 100 C. Its pH is below 1.
The reconstituted modified acid composition of Example 3 was also tested for
skin corrosiveness
and deemed non-corrosive to the skin. Oral toxicity was calculated using the
LD50 rat model and deemed
to be of low oral toxicity. It is considered readily biodegradable and offers
a lower bioaccumulative
potential when compared to 15% Hydrochloric acid.
Canadian Patent 2,974,757 discloses the dermal safety data for modified acid
composition
comprising lysine and HC1 in various molar ratios. The patent also discloses
the scale solubility and
dissolution power of such compositions, the disclosure in CA 2,974,757 is
hereby incorporated in its
entirety. These compositions are similar to the reconstituted lysine-HC1-
containing modified acid
composition discussed herein. The teachings of Canadian Patent 2,974,757 are
hereby incorporated by
reference.
18
Date Recue/Date Received 2022-01-21
Stability Testing of a reconstituted modified acid composition comprising
lysine and HC1
Testing was carried out using pressurized ageing cell with Teflon liner in
order to assess the stability
of various lysine-HC1 compositions obtained from the mixing of saturated or
supersaturated aqueous lysine
monohydrochloride compositions with commercial grade Hydrochloric acid. The
tests were conducted at
a pressure of 300 psi (denoted by an asterisk) and at 400 psi established that
lysine-HC1 compositions
obtained mixing of saturated or supersaturated aqueous lysine
monohydrochloride compositions with
commercial grade Hydrochloric acid are stable when exposed to temperatures
above 200 C.
SCALE SOLUBILITY
The power of a modified acid composition comprising lysine and HC1 obtained
from the mixing of
a premix comprising a saturated or near saturated aqueous lysine
monohydrochloride composition with
commercial grade Hydrochloric acid to dissolve scale was assessed. It was
determined that a modified
acid composition obtained from the mixing of saturated or supersaturated
aqueous lysine
monohydrochloride compositions with commercial grade hydrochloric acid
provides an excellent
solubilizing ability when dealing with various oilfield scales. Its
solubilizing ability is comparable to the
solubility of most many mineral and organic acid packages typically utilized.
ELASTOMER COMPATIBILITY
When common sealing elements used in the oil and gas industry come in contact
with acid
compositions they tend to degrade or at least show sign of damage. A number of
sealing elements common
to activities in this industry were exposed to a composition according to a
preferred embodiment of the
present invention to evaluate the impact of the latter on their integrity.
More specifically, the hardening and
drying and the loss of mechanical integrity of sealing elements can have
substantial consequences on the
efficiency of certain processes as breakdowns require the replacement of
defective sealing elements.
Testing was carried out to assess the impact of the exposure of composition of
Example 2 to various
elastomers and was found to be stable for the period of time tested.
According to a preferred embodiment of the present invention, the resulting
acidic composition
will, upon proper use, results in a very low corrosion rate on oil and gas
industry tubulars and equipment
compared to mineral acids, such as Hydrochloric acid.
According to a preferred embodiment of the present invention, the
reconstituted lysine-HC1-
containing modified acid composition can be used in the oil industry and is
biodegradable.
19
Date Recue/Date Received 2022-01-21
According to a preferred embodiment of the present invention, the
reconstituted lysine-HC1-
containing modified acid composition can be used in the oil industry as it
possesses a controlled, more
methodical spending (reacting) nature that is near linear as temperature
increases, low- fuming/vapor
pressure, low- toxicity, and has a highly controlled manufacturing process
ensuring consistent end product
strength and quality.
According to another preferred embodiment of the present invention, there is
provided an aqueous
modified acid composition (referred to as the reconstituted aqueous modified
acid composition) for use in
the oil industry which has a pH below 1. According to another preferred
embodiment of the present
invention, there is provided an aqueous synthetic acid composition for use in
the oil industry which will
keep iron particles and solubilized carbonate in solution even as the pH rises
to a level > 4 pH. According
to another preferred embodiment of the present invention, there is provided an
aqueous synthetic acid
composition for use in the oil industry which will provide a thermal stability
at temperatures above 100 C.
According to another preferred embodiment of the present invention, there is
provided a synthetic acid
composition for use in the oil industry which will provide corrosion
protection at an acceptable oilfield
limit when said composition is in contact with metal components and is at
temperatures ranging from 100
C to 220 C. According to a preferred embodiment of the present invention,
there is provided a modified
acid composition for use in the oil industry which has minimal exothermic
reactivity upon dilution or during
the reaction process.
Preferably, the reconstituted aqueous modified acid composition for use in the
oil industry is
compatible with existing industry acid additives. According to another
preferred embodiment of the present
invention, there is provided an aqueous synthetic acid composition for use in
the oil industry which has
higher salinity tolerance. A tolerance for high salinity fluids, or brines, is
desirable for onshore and offshore
acid applications. Conventional acids are normally blended with fresh water
and additives, typically far
offsite, and then transported to the area of treatment as a finished blend. It
is advantageous to have an
alternative that can be transported as a concentrate safely to the treatment
area, then blended with a saline
produced water or sea water greatly reducing the logistics requirement. A
conventional acid system can
precipitate salts/minerals heavily if blended with fluids of an excessive
saline level resulting in formation
plugging or ancillary damage, inhibiting production and substantially
increasing costs. Brines are also
typically present in formations, thus having an acid system that has a high
tolerance for brines greatly
reduces the potential for formation damage or emulsions forming down-hole
during or after product
placement/spending (reaction) occurs. According to another aspect of the
present invention, there is
provided an aqueous modified acid composition for use in the oil industry
which is immediately reactive
Date Recue/Date Received 2022-01-21
upon contact/application. According to another aspect of the present
invention, there is provided an
aqueous modified acid composition for use in the oil industry which results in
less unintended near wellbore
erosion or face dissolution due to a more controlled reaction rate. This, in
turn, results in deeper formation
penetration, increased permeability, and reduces the potential for zonal
communication during a typical
'open hole' mechanical isolation application treatment. As a highly reactive
acid, such as hydrochloric acid,
is deployed into a well that has open hole packers for isolation (without
casing) there is a potential to cause
a loss of near-wellbore compressive strength resulting in communication
between zones or sections of
interest as well as potential sand production, and fines migration. It is
advantageous to have an alternative
that will react with a much more controlled rate or speed, thus greatly
reducing the potential for zonal
communication and the above potential negative side effects of traditional
acid systems. According to a
preferred embodiment of the present invention, there is provided an aqueous
synthetic acid composition for
use in the oil industry which provides a controlled and comprehensive reaction
rate throughout a broad
range of temperatures up to 220 C.
Upon reconstitution, additional chemical may be added to the reconstituted
modified acid
compositions prior to use. These include but are not limited to corrosion
inhibitors, scale inhibitors,
demulsifiers, reducing agents and/or chelants. For example, non-surface active
substituted ammonium
containing amino acid derivatives may be used as environmentally friendly
corrosion inhibitors that
effectively protect various tools employed in oilfield operations by surface
treating these tools.
According to a preferred embodiment of the present invention, the corrosion
inhibitor is typically
provided in liquid form and is mixed with the other components of the
treatment fluid at the surface and
then introduced into the formation. The corrosion inhibitor package can be
present in an amount ranging
from 0.1 wt % to about 5 wt. %, more preferably 0.2 wt.% to 3 wt.% of the
total weight of the composition
used in the treatment operations. Preferably, the corrosion inhibitor used
with the fluids of the present
disclosure includes an alkyl, alkenyl, alycyclic or aromatic substituted
aliphatic ketone, which includes
alkenyl phenones, or an aliphatic or aromatic aldehyde, which includes alpha,
or beta-unsaturated
aldehydes, or a combination of these. Alkyl, alycyclic or aromatic phenone and
aromatic aldehyde
compounds may also be used in certain applications. According to another
preferred embodiment, other
unsaturated ketones or unsaturated aldehydes are used. According to another
preferred embodiment,
alkynol phenone, aromatic and acetylenic alcohols and quaternary ammonia
compounds, and mixtures of
these are used. According to another preferred embodiment, a solvent is
present. Preferably, the solvent is
an alcohol is selected from the group comprising, but not limited to:
methanol, ethanol, isopropanol, butanol
21
Date Recue/Date Received 2022-01-21
or the like. Other additives may also be used according to other preferred
embodiments of the present
invention.
According to a preferred embodiment of the present invention, alcohols and
derivatives thereof,
such as alkyne alcohols and derivatives and preferably propargyl alcohol and
derivatives thereof can be
used as corrosion inhibitors with the reconstituted modified acid
compositions. Propargyl alcohol itself is
traditionally used as a corrosion inhibitor which works well at low
concentrations. It is however a very
toxic/flammable chemical to handle as a concentrate, so care must be taken
when exposed to the
concentrate. In some cases, it is preferred to use 2-Propyn- I-ol, complexed
with methyloxirane, as this is
a much safer derivative to handle. Basocorr PP is an example of such a
compound. In preferred
embodiments of the present invention, 2- Propyn- I-ol, complexed with
methyloxirane is present in an
amount ranging from 20% to 55% by volume of the total volume of the corrosion
inhibition package.
According to another preferred embodiment of the present invention, terpenes
can be used to achieve
desirable corrosion inhibition results. Preferably, the terpene is selected
from the group consisting of:
monoterpenes (acyclic); monocyclic terpenes; and beta-ionone. Exemplary but
non-limiting compounds
of some of the previously listed terpene sub-classes comprise: for
monoterpenes: citral (mixture of geranial
and neral); citronellal; geraniol; and ocimene; for monocyclic terpenes: alpha-
terpinene; carvone; p-
cymene. More preferably, the terpenes are selected from the group consisting
of: citral; ionone; ocimene;
and cymene.
According to a preferred embodiment of the present invention, the corrosion
inhibition package
used with the reconstituted modified acid compositions comprises a surfactant
which is environmentally
friendly. More preferably, the surfactant is capable of withstanding exposure
to temperatures of up to least
220 C for a duration of 2 to 4 hours in a closed environment without
undergoing degradation. Preferably,
there may be at least one amphoteric surfactant selected from the group
consisting of: a sultaine surfactant;
a betaine surfactant; and combinations thereof. More preferably, the sultaine
surfactant and betaine
surfactant are selected from the group consisting of: an amido betaine
surfactant; an amido sultaine
surfactant; and combinations thereof. Yet even more preferably, the amido
betaine surfactant and is
selected from the group consisting of: an amido betaine comprising a
hydrophobic tail from Cs to C16. Most
preferably, the amido betaine comprising a hydrophobic tail from C8 to C16 is
cocamidobetaine.
According to a preferred embodiment of the present invention, the corrosion
inhibition package
further comprises an anionic surfactant. Preferably, the anionic surfactant is
a carboxylic surfactant. More
preferably, the carboxylic surfactant is a dicarboxylic surfactant. Even more
preferably, the dicarboxylic
22
Date Recue/Date Received 2022-01-21
surfactant comprises a hydrophobic tail ranging from C8 to C16. Most
preferably, the dicarboxylic surfactant
is sodium lauriminodipropionate Most preferred are embodiments of a corrosion
inhibition package
comprising cocamidopropyl betaine and B-Alanine, N-(2-carboxyethyl)-N-dodecyl-
, sodium salt (1:1).
According to a preferred embodiment of the present invention, when preparing
an acidic composition
comprising a corrosion inhibition package, metal iodides or iodates such as
potassium iodide, sodium
iodide, cuprous iodide and lithium iodide can be added as corrosion inhibitor
intensifier. The iodide or
iodate is preferably present in a weight/volume percentage ranging from 0.1 to
1.5%, more preferably from
0.25 to 1.25%, yet even more preferably 1% by weight/volume of the acidic
composition. Most preferably,
the iodide used is potassium iodide. According to a preferred embodiment of
the present invention, the
corrosion package comprises: 2-Propyn-1-ol, compd. with methyloxirane; B-
Alanine, N-(2-carboxyethyl)-
N- dodecyl-, sodium salt (1:1); cocamidopropyl betaine; 3,7-Dimethy1-2,6-
octadienal (Citral); and
isopropanol. More preferably, the composition comprises 38.5% of 2-Propyn- I -
ol, compd. with
methyloxirane; 5% of B- Alanine, N-(2-carboxyethyl)-N-dodecyl-, sodium salt
(1:1); 5% of
cocamidopropyl betaine; 20% of 3,7-Dimethy1-2,6-octadienal (Citral); and 31.5%
of lsopropanol (all
percentages are volume percentages).
According to a preferred embodiment of the present invention, the compositions
may further
comprise a chelating agent to control and remove undesirable metal ions.
Preferably one of the following
type of chelating agents can be employed with the reconstituted modified acid
compositions according to
the present invention: polycarboxylic acids (including aminocarboxylic acids
and polyaminopolycarboxylic
acids) and phosphonates. The non-surface active substituted ammonium
containing amino acid derivatives
may act as chelating agents when present in the reconstituted modified acid
compositions in amount of
from about 0.05% to about 10% or from about 1 wt % to about 5 wt %, based on
total weight percent of the
reconstituted modified acid compositions.
According to a preferred embodiment of the present invention, the
reconstituted lysine-HC1-
containing modified acid composition can be used in a molar ratio ranging from
1:3.5 to 1:12.5 for injection
into an oil or gas well to perform a treatment with said composition;
recovering the spent acid from the
well; and sending the spent acid to a plant.
According to a preferred embodiment of the present invention, the
reconstituted lysine-HC1-
containing modified acid composition can be used to overcome many of the
drawbacks found in the use of
compositions of the prior art related to the oil & gas industry.
23
Date Recue/Date Received 2022-01-21
According to a preferred embodiment of the present invention, the
reconstituted lysine-HC1-
containing modified acid composition can be used in a method of matrix
acidizing a hydrocarbon-
containing dolomite formation, said method comprising: - providing a
composition comprising a HC1 and
lysine mixture and water; wherein the molar ratio between the HC1 and the
lysine ranges from 4.5:1 to
8.5:1, - injecting said composition downhole into said formation at a pressure
below the fracking pressure
of the formation; and - allowing a sufficient period of time for the
composition to contact said formation to
create wormholes in said formation.
According to a preferred embodiment of the present invention, the
reconstituted lysine-HC1-
containing modified acid composition can be used in the oil industry to
perform an activity selected from
the group consisting of: stimulate formations; assist in reducing breakdown
pressures during downhole
pumping operations; treat wellbore filter cake post drilling operations;
assist in freeing stuck pipe; descale
pipelines and/or production wells; increase injectivity of injection wells;
lower the pH of a fluid; remove
undesirable scale on a surface selected from the group consisting of:
equipment, wells and related
equipment and facilities; fracture wells; complete matrix stimulations;
conduct annular and bullhead
squeezes & soaks; pickle tubing, pipe and/or coiled tubing; increase effective
permeability of formations;
reduce or remove wellbore damage; clean perforations; and solubilize
limestone, dolomite, calcite and
combinations thereof; said composition comprising lysine and HC1 in a molar
ratio ranging from 1:2.1 to
1:12.5. Preferably, the composition comprises lysine and HC1 in a molar ratio
ranging from 1:4.5 to 1:8.5.
Uses of a reconstituted modified acid composition comprisin2 lysine and HC1
accordin2 to a preferred
embodiment of the present invention
The uses (or applications) of the reconstituted modified acid composition
comprising lysine and
HC1 according to the present invention upon dilution thereof ranging from
approximately 1 to 90% dilution
are listed below in Table 5 and include, but are not limited to:
injection/disposal treatments; matrix acid
squeezes, soaks or bullheads; acid fracturing, acid washes; fracturing
spearheads (breakdowns); pipeline
scale treatments, cement breakdowns or perforation cleaning; pH control; and
de-scaling applications, high
temperature (up to 180 C) cyclical steam scale treatments and steam assisted
gravity drainage (SAGD)
scale treatments (up to 220 C) As would be understood by the person skilled in
the art, the methods of use
generally comprise the following steps: providing a composition according to a
preferred embodiment of
the present; exposing a surface (such as a metal surface) to the acid
composition; allowing the acid
composition a sufficient period of time to act upon said surface; and
optionally, removing the acid
composition when the exposure time has been determined to be sufficient for
the operation to be complete
or sufficiently complete. Another method of use comprises: injecting the acid
composition into a well and
24
Date Recue/Date Received 2022-01-21
allowing sufficient time for the acid composition to perform its desired
function. Yet another method
according to the present invention comprises the steps of: providing a
composition according to a preferred
embodiment of the present; injecting the composition into a well; an optional
step of dilution of the acid
composition can be performed if deemed necessary prior to injection downhole;
monitoring the various
injection parameters to ensure that the pressure and rate of injection are
below frac pressures and below
conventional injection rates used for conventional acids such as Hydrochloric
acid ; allowing sufficient
period of time to act upon said formation to obtain the desired wormholing
effect; and optionally, removing
the acid composition when the exposure time has been determined to be
sufficient for the operation to be
complete or sufficiently complete.
Yet another method of use comprises: exposing the acid composition to a body
of fluid (typically
water) requiring a decrease in the pH and allowing sufficient exposure time
for the acid composition to
lower the pH to the desired level.
Table 5 - Applications for which compositions according to the present
invention can be used
as well as proposed dilution ranges
=kpplicalion Sti2!4csIctl
Diltilion Benefits
Injection/Disposal Wells 10-75% Compatible with mutual solvents and
solvent blends,
very cost effective.
Squeezes & Soaks 33% - 75% Ease of storage & handling, cost
effective compared to
conventional acid stimulations. Ability to leave pump
- Bullhead equipment in wellbore.
- Annular
Acid Frac s / matrix 50% - 90% Decreased shipping and storage
compared to
treatments. Produciton well conventional acid, no blend
separation issues,
and pipeline scale treatments comprehensive spend rate encourages
deeper formation
penetration.
Frac Spearheads (Break- 33% - 90% Able to adjust concentrations on
the fly. Decreased
downs) shipping and storage on location.
Cement Break-downs 20-90% Higher concentrations recommended
due to lower
temperatures, and reduced solubility of aged cement.
pH Control 0.1% - 10.0% Used in a variety of applications
to adjust pH level of
water based systems.
Liner De-Scaling, Heavy Oil 1% - 75% Continuous injection/de-scaling of
slotted liners,
typically at very high temperatures.
Date Recue/Date Received 2022-01-21
The main advantages of the use of the synthetic acid composition included: the
reduction of the
total loads of acid, and the required number of tanks by delivering
concentrated product to location and
diluting with fluids available on location (with low to high salinity
production water). Other advantages of
the composition according to the present invention include: operational
efficiencies which lead to the
elimination of having to periodically circulate tanks of Hydrochloric acid
acid due to chemical separation;
reduced corrosion to downhole tubulars; ultra-high temperature corrosion
protection up to 220 C, less
facility disruptions due to iron pick up and precipitation, thermal stability
of a synthetic acid, and reduced
hazardous Hydrochloric acid acid exposure to personnel and environment by
having a non-low hazard, low
fuming acid (lower vapour pressure) on location. A synthetic acid composition
according to a preferred
embodiment of the present invention, can be used to treat scale formation in
SAGD operations at ultra-high
temperatures (up to 220 C) while achieving acceptable corrosion limits set by
industry. This also eliminates
the need for the SAGD operation to be halted for a 'cool down' prior to a
scale treatment and said synthetic
acid is injected into said well to treat scale formation inside said well at
high temperatures.
While the foregoing invention has been described in some detail for purposes
of clarity and
understanding, it will be appreciated by those skilled in the relevant arts,
once they have been made familiar
with this disclosure that various changes in form and detail can be made
without departing from the true
scope of the invention in the appended claims.
26
Date Recue/Date Received 2022-01-21
