Note: Descriptions are shown in the official language in which they were submitted.
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A Method of Gravel Packing a Well
Field of the Invention
The present invention provides a novel particulate material for treatment of
subterranean formations. More particularly, it relates to gravel packing.
Gravel packing is used for sand control purposes. A typical gravel pack job
includes downhole installation of a screen and injection of gravel between the
screen
and the perforated casing. The gravel prevents the formation sand from
entering the
well, whilst the reservoir fluids are allowed to flow into the well through
the gravel
and the screen. Occasionally, the gravel pack can be placed downhole without a
screen.
The success of gravel pack operations strongly relies on the ability of the
treating fluids to suspend and transport gravel. The transport of particles is
critical in
horizontal and deviated wells.
The purpose of the present invention is to provide an improved method of
treating the formation by using polyDCPD materials as gravel. These materials
have
relatively low specific gravity and high compressive strength. Particles made
of
polyDCPD can be easily transported by the treating fluid as neutrally buoyant.
The
use of these particles is particularly beneficial in operations where carrier
fluid
viscosities are low.
Prior Art
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A variety of sand control methods using various types of gravel packing are
known. Possible solutions are disclosed in the following patents:
1. US7255168, this Patent discloses composite particulates and methods of
using
such particulates in subterranean applications. The composite particulate
comprises a homogeneous mixture of polyethylene terephthalate (PET) and a
filler material. The filler material can contain from about 5% to about 70% by
weight of the overall particulate. It can be any micro-sized particle that is
compatible with the thermoplastic material, such as cenospheres,
microspheres, fly ash, etc.
2. US7281580, this patent discloses a method of fracturing by using adhesive-
coated, high-density plastic particles.
The method, which seems closest to the present Invention, is the one described
in
Patent GB2436011. The latter discloses the use of a proppant made of polyamide
for fracturing and sand control. However, the main disadvantage of this method
is
a lower level of strength.
Summary of the Invention
The improved method of sand control of the present Invention consists in
placing a
gravel pack in a well using a novel type of particulate material that posseses
high
crushing strength and chemical inertness. The method consists in creating a
gravel
pack in a well by injecting a slurry that contains a fluid and a particulate
material
comprising particles made of polydicyclopentadiene (hereinafter referred to as
polyDCPD). =
The engineering result achieved through the implementation of the present
invention is providing a better retention of formation sand and other small
particles
due to a more uniform packing of gravel. Since the specific gravity of
PoIyDCPD
particles is close to 1, the gravel settling velocity is negligible and
particles can be
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transported in a neutrally buoyant manner, which is especially beneficial in
gravel
packing of deviated and horizontal wells.
This technical result is attained by using the method of the present
invention, i.
e. the creation of a gravel pack in a well by injecting a slurry that contains
a fluid and
a particulate material comprising particles made of polydicyclopentadiene. The
gravel particles can be of any size, shape and mixtures of various shapes and
sizes.
Non-spherical particles can be elongated, prolate, polygonal, cubic, fibrous
etc. The
PoIyDCPD gravel of the present Invention can be reinforced with suitable
filler
materials such as clay, silica, fibers, ceramic etc.
Patent search resulted in finding no solutions containing the entire
combination
of the features claimed, which enables making the conclusion of the compliance
of
the present Invention with the "novelty" criterion.
Description
The present invention relates to the use of polyPCPD particles as gravel in
gravel packing operations. The PoIyDCPD gravels of the present Invention are
lightweight and high strength particles made of PoIyDCPD. PoIyPCPD has a
compressive strength of up to approximately 60 MPa and a density of
approximately
0.95-1.03 g/cm3. Therefore, particles made of polyPCPD can be easily suspended
and
transported by a treating fluid in a neutrally buoyant manner.
The advantage of the present Invention is that a more uniform packing of
gravel
and its high strength provides better retention of formation sand, whilst
keeping_
sufficient gravel pack permeability. Since the specific gravity of PoIyDCPD
particles
is close to 1, the gravel settling is negligible even in low-viscosity carrier
fluids, such
as water. Thus, a more uniform packing of particles is achieved. Negligible
settling
velocity is especially beneficial in gravel packing of deviated and horizontal
wells.
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Moreover, the present Invention allows avoiding the use of highly viscous
fluids and
therefore, reducing the formation damage that these fluids induce.
Among polymer materials, PoIyDCPD possesses a unique combination of
mechanical, chemical and physical properties, which makes it a good
alternative to
polyethylene, polystyrene, fiberglass, polyether, carbon fiber, aluminum
alloys, and
other materials. PoIyDCPD is characterized by low density (close to the
density of
water), excellent combination of stiffness and impact resistance, as well as
high
chemical and temperature resistance.
The gravel particles of the present Invention can be of any size, shape and
mixtures of various shapes and various sizes. Non-spherical proppants can be
elongated, prolate, polygonal, cubic, fibrous etc. The PoIyDCPD gravel of the
present
Invention can be reinforced with suitable filler materials, such as clay,
silica, fibers,
ceramic etc.
High-purity polyDCPD Noveon is manufactured by "Telene DCPD" Company
for European and Chinese markets.
PoIyDCPD "Metton8n PDCPD", which is basically similar to "Telene ", is
manufactured by Metton America Inc. and applied for large scale production as
an
alternative of fiberglass, wood or metal.
The invention complies with "industrial applicability" criterion since its
implementation will require using existing production facilities and applying
known
technologies.
