Note: Descriptions are shown in the official language in which they were submitted.
SELECTING POTENTIAL WELL LOCATIONS
IN A RESERVOIR GRID MODEL
FIELD OF THE DISCLOSURE
[0001] The present disclosure generally relates to systems and methods for
selecting
potential well locations in a reservoir grid model. More particularly, the
present disclosure
relates to selecting potential well locations in a reservoir grid model using
a bounding box with
grid-block dimensions to calculate a total original gas-in-place (OGIP) and/or
original oil-in-
place (00IP) for each bounding box associated with a potential well location.
BACKGROUND
[0002] In the oil and gas industry, a field development plan (FDP) is
necessary before
development of an oil or gas field may begin. An FDP is based on a numerical
reservoir
simulation model also referred to as a reservoir grid model. The reservoir
grid model includes
multiple grid-blocks of the same size and predetermined dimensions (DX, DY,
DZ). Each grid-
block includes information about the reservoir such as, for example, porosity
for each grid
block: (I), initial water saturation for each grid block: Swi, and net to
gross ratio for each grid
block: NTG. The reservoir grid model includes grid-block dimensions (i, j, k)
that represent the
number of grid-blocks in each dimension. The main objective of the FDP is to
optimize
hydrocarbon recovery by determining the best number of potential wells, their
type and
location. Vertical wells are a natural first choice due to their ease of
drilling, low cost and low
risk.
[0003] Reservoir simulation normally takes a long time to run especially for
large
reservoir grid models. Previous attempts require a large number of simulation
runs no matter
what advanced mathematical or statistical method is used. The reason is that
every move of a
potential well to a new location would warrant a new simulation run. For
example, for a simple
1
CA 2975437 2018-12-21
case with 2 wells to be optimized and 10 potential locations for each well, it
would require
10x 10 = 100 simulation runs to investigate all possible combinations of well
locations. For the
optimization of a large number of wells, the number of the simulation runs
needed is cost
and/or time prohibitive.
SUMMARY
[0004] In accordance with a first broad aspect, there is provided a method for
selecting
potential well locations in a reservoir, which comprises a) selecting a
bounding box with grid-
block dimensions, b) selecting a surface grid-block for a potential well
location in a reservoir
grid model comprising multiple grid-blocks, c) positioning the bounding box
around the surface
grid-block, d) calculating a total original gas-in-place in the bounding box
using an original gas-
in-place for each grid-block in the bounding box, e) repeating steps b) ¨ d)
for each surface grid-
block in the reservoir grid model using a computer processor, and f) selecting
a largest total
original gas-in-place calculated for a bounding box, which represents a
bounding box with
surface grid-block coordinates for a best well location.
[0005] In accordance with a second broad aspect, there is provided a non-
transitory
program carrier device tangibly carrying computer-executable instructions for
selecting
potential well locations in a reservoir, the instructions being executable to
implement a)
selecting a bounding box, b) selecting a surface grid-block for a potential
well location in a
reservoir grid model comprising multiple grid-blocks, c) positioning the
bounding box around
2
CA 2975437 2018-12-21
the surface grid-block, d) calculating a total original gas-in-place in the
bounding box using an
original gas-in-place for each grid-block in the bounding box, e) repeating
steps b) ¨ d) for
each surface grid-block in the reservoir grid model, f) selecting a largest
total original gas-in-
place calculated for a bounding box, which represents a bounding box with
surface grid-block
coordinates for a best well location, and g) selecting each total original gas-
in-place calculated
for a bounding box positioned around a surface grid-block that is within a
predetermined
number of surface grid-blocks from the surface grid-block with coordinates for
the best well
location.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present disclosure is described below with references to the
accompanying
drawings in which like elements are referenced with like reference numerals,
and in which:
[0007] FIGS. 1A-1B. are a flow diagram illustrating one embodiment of a method
for
implementing the present disclosure.
[0008] FIG. 2. is a display of a partial reservoir grid model illustrating
step 106 in FIG.
1A.
[0009] FIG. 3. is a display of a partial reservoir grid model illustrating
steps 108-110 in
FIG. 1A.
[0010] FIG. 4 is a block diagram illustrating one embodiment of a computer
system for
implementing the present disclosure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] The present disclosure overcomes one or more deficiencies in the prior
art by
2a
CA 2975437 2018-12-21
CA 02975437 2017-07-31
WO 2016/140645
PCT/US2015/018319
providing systems and methods for selecting potential well locations in a
reservoir grid model
using a bounding box with grid-block dimensions to calculate a total original
gas-in-place
(OGIP) and/or original oil-in-place (00IP) for each bounding box associated
with a potential
well location,
[0012] In one embodiment, the present disclosure includes a method for
selecting
potential well locations in a reservoir, which comprises: a) selecting a
bounding box with grid-
block dimensions; b) selecting a surface grid-block for a potential well
location in a reservoir
grid model comprising multiple grid-blocks; c) positioning the bounding box
around the
surface grid-block; d) calculating a total original gas-in-place in the
bounding box using an
original gas-in-place for each grid-block in the bounding box; e) repeating
steps b) d) for
each surface grid-block in the reservoir grid model using a computer
processor; and f) selecting
a largest total original gas-in-place calculated for a bounding box, which
represents a bounding
= box with surface grid-block coordinates for a best well location,
[0013] In another embodiment, the present disclosure includes a non-transitory
program
carrier device tangibly carrying computer-executable instructions for
selecting potential well
locations in a reservoir, the instructions being executable to implement: a)
selecting a bounding
box with grid-block dimensions; b) selecting a surface grid-block for a
potential well location
in a reservoir grid model comprising multiple grid-blocks; c) positioning the
bounding box
around the surface grid-block; d) calculating a total original gas-in-place in
the bounding box
using an original gas-in-place for each grid-block in the bounding box; e)
repeating steps b) ¨
d) for each surface grid-block in the reservoir grid model; and 0 selecting a
largest total
original gas-in-place calculated for a bounding box, which represents a
bounding box with
3
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645
PCT/US2015/018319
surface grid-block coordinates for a best well location.
[0014] In yet another embodiment, the present disclosure includes a non-
transitory
program carrier device tangibly carrying computer-executable instructions for
selecting
potential well locations in a reservoir, the instructions being executable to
implement; a)
selecting a bounding box; b) selecting a surface grid-block for a potential
well location in a
reservoir grid model comprising multiple grid-blocks; c) positioning the
bounding box around
the surface grid-block; d) calculating a total original gas-in-place in the
bounding box using an
original gas-in-place for each grid-block in the bounding box; e) repeating
steps b) ¨ d) for
each surface grid-block in the reservoir grid model; f) selecting a largest
total original gas-in-
place calculated for a bounding box, which represents a bounding box with
surface grid-block
coordinates for a best well location; and g) selecting each total original gas-
in-place calculated
for a bounding box positioned around a surface grid-block that is within a
predetermined
number of surface grid-blocks from the surface grid-block with coordinates for
the best well
location.
[0015] The subject matter of the present disclosure is described with
specificity;
however, the description itself is not intended to limit the scope of the
disclosure, The subject
matter thus, might also be embodied in other ways, to include different steps
or combinations
of steps similar to the ones described herein, in conjunction with other
present or future
technologies. Moreover, although the term "step" may be used herein to
describe different
elements of methods employed, the term should not be interpreted as implying
any particular
order among or between various steps herein disclosed unless otherwise
expressly limited by
the description to a particular order. While the present disclosure may be
applied in the oil and
4
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645
PCT/US2015/018319
gas industry, it is not limited thereto and may also be applied in other
industries such as, for
example, water or coal exploration to achieve similar results.
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645
PCT/US2015/018319
Method Description
[0016] Logically, a well drilled through grid-blocks with higher permeability
and/or
QUIP would have an anticipated higher production. For a conventional oil or
gas reservoir,
long-term performance of a well is more dependent on the OGIP connected to the
well rather
than on permeability. In addition, permeability is usually positively
correlated with porosity (or
pore volume). As such, the sum of ()GIP for the grid-blocks to be penetrated
by a potential
well and the neighboring grid-blocks is an indicator of where the potential
well should be
located. In the following description, a gas field is chosen as the example
for conciseness, but
the method can also be applied to an oil field.
[0017] Referring now to FIGS. 1A-1B, a flow diagram of one embodiment of a
method
100 for implementing the present disclosure is illustrated,
[0018] In step 102, a bounding box is automatically selected with grid-block
dimensions
(i, j, k). Alternatively, the bounding box may be selected using the client
interface and/or the
video interface described further in reference to FIG. 4, Preferably, the (i,
j) grid-block
dimensions are the same odd number representing a preferred length and width
of the bounding
box and the k grid-block dimension represents the depth of the bounding box
that substantially
conesponds to the grid-block depth of the reservoir grid model. The (i, j)
grid-block
dimensions may be arbitrarily selected or they may be based on drainage area
or trial and error.
[0019] In step 104, any surface grid-block is selected for a potential well
location in a
reservoir grid model. Any surface grid-block in the reservoir grid model may
be selected as a
potential well location because step 112 will repeat until every surface grid-
block in the
reservoir grid model has been selected for a potential well location. And,
only the surface grid-
6
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645
PCT/US2015/018319
blocks are considered for potential well locations because the potential wells
are vertical wells
and each vertical well will pass through the same respective (i, j) grid-block
coordinates in the
reservoir grid model.
[0020] In step 106, the bounding box selected in step 102 is positioned around
the
surface grid-block selected in step 104 so that one side of the bounding box
is coterminous
with an exterior side of the surface grid-block selected in step 104 and the
surface grid-block is
equidistant between the (i, j) grid-block dimensions of the bounding box, In
FIG, 2, for
example, a display 200 of a partial reservoir grid model may be used to
illustrate this step. The
bounding box 202 is positioned around the surface grid-block 204 selected for
a potential well
location 206. Only one side of the bounding box 202 is visible in the display
200. This side of
the bounding box 202 is coterminous with an exterior side of the surface grid-
block 204 and
the surface grid-block 204 is equidistant between the (i, j) grid-block
dimensions (5x5) of the
bounding box 202.
[0021] In step 108, the QUIP is calculated for each grid-block in the bounding
box
positioned in step 106. OGIP¨DX*DY*DZ*4*NTG*(1-Swi) wherein each grid-block
includes
the same predetermined dimensions (DX, DY, DZ) and information about the
reservoir such
as, for example, porosity for each grid block: 0, initial water saturation for
each grid block:
Swi, and net to gross ratio for each grid block: NTG. In FIG. 3, for example,
a display 300 of a
partial reservoir grid model may be used to illustrate this step. The bounding
box 302 is
positioned around the surface grid-block 304 selected for a potential well
location 306. The
OGIP is calculated for each grid-block in the bounding box 302, which includes
(i, j) grid-
block dimensions (5x5) and the k grid-block dimension 308 shown in an exploded
view.
7
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645
PCT/US2015/018319
[0022] In step 110, the total OGIP in the bounding box is calculated using the
OGIP for
each grid-block calculated in step 108. In FIG. 3, for example, the OGIP for
each grid-block in
the bounding box 302 is summed for the total OGIP in the bounding box 302.
[0023] In step 112, the method 100 determines if there is another surface grid-
block for
a potential well location in the reservoir grid model, If there is another
surface grid-block for a
potential well location in the reservoir grid model, then the method 100
returns to step 104 to
select another surface grid-block for a potential well location in the
reservoir grid model.
Otherwise, the method 100 proceeds to step 114.
[0024] In step 114, the total OGIP calculated in step 110 for each bounding
box
associated with a potential well location is ranked from largest to smallest
or vice versa. Each
surface grid-block selected for a potential well location in the reservoir
grid model is thus,
ranked in this manner.
[0025] In step 116, the largest total OGIP from step 114 is selected, which
represents
the bounding box with the (i, j) surface grid-block coordinates for the best
potential well
location.
[0026] In step 118, the method 100 determines if there is another total OGIP
from step
114 that has not been selected in step 116 or step 124. If there is not
another total OGIP from
step 114 that has not been selected, then the method 100 ends with the (i, j)
surface grid-block
coordinates for the best potential well location and, preferably, one or more
(i, j) surface grid-
block coordinates for the next best potential well location(s), It is
possible, however, that the
method 100 may end with only the (i, j) surface grid-block coordinates for the
best potential
well location. If there is another total OGIP from step 114 that has not been
selected, then the
8
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645
PCT/US2015/018319
method 100 proceeds to step 120.
[0027] In step 120, the next largest total OGIP from step 114 is identified.
[0028] In step 122, the method 100 determines if the surface grid-block for
the potential
well location associated with the boundary box for the next largest total OGIP
identified in step
120 is within a predetermined number of surface grid-blocks from the surface
grid-block with
the best potential well location selected in step 116. If the surface grid-
block for the potential
well location associated with the boundary box for the next largest total OGIP
identified in step
120 is not within a predetermined number of surface grid-blocks from the
surface grid-block
with the best potential well location selected in step 116, then the method
100 returns to step
118. Otherwise, the method 100 proceeds to step 124. A predetermined number of
surface
grid-blocks is used to prevent selected wells from clustering around areas
with good reservoir
properties. While the predetermined number of surface grid-blocks may be
arbitrarily selected
or may be based on the economics of drilling a well, at least two grid-blocks
should be used
because the selected wells would otherwise be too close for accurate reservoir
simulation.
[0029] In step 124, the next largest total OGIP identified in step 120 is
selected, which
represents the bounding box with the (i, j) surface grid-block coordinates for
the next best
potential well location. The method 100 then returns to step 118.
[0030] When applied to an oil field, the method 100 will replace OGIP with
00IP=DX*DY*DZ*o*NTG*(1-Swi). At the end of the method 100, the results may be
used
to determine the type and number of wells in the FDP and, most importantly,
their location to
begin drilling operations. If, for example, there are ten potential well
locations selected by the
method 100 in a ranked order starting with the best, the next best and so on,
the best two
9
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645
PCT/US2015/018319
locations may be selected if the financial constraints are limited to two
wells. Optionally, the
bounding box size in step 102 and the predetermined number of surface grid-
blocks (i.e.
minimum well spacing) in step 122 can be varied with each iteration of the
entire method 100
to compare the differences, if any, and optimize the selection of the best
potential well
locations with highest potential oil and/or gas recovery. The method 100
therefore, is very
efficient and flexible for selecting the best potential well locations by
using a bounding box
and a predetermined minimum well spacing (i,e, predetermined number of surface
grid-
blocks). And, the method 100 requires fewer simulation runs compared to
conventional
techniques. Only one simulation run is required for each iteration of the
method 100. In most
cases, less than ten simulation runs are required to obtain the optimal
potential well locations
regardless of the number of potential well locations (i.e. grid-blocks), As a
result, a lot of time
can be saved for the design of an FDP.
[0031] Take for example, a typical reservoir grid model with grid-block
dimensions
100x100x20 and 10 planned wells. One conventional well location optimization
technique
moves all 10 planned wells around each potential well location in the
reservoir grid model.
One simulation run is required after every move of a well to a new potential
well location. If
each well has just 10 potential well locations, then the total number of
simulation runs needed
for a complete combination is 1010, which is ten billion. Even by using some
advanced
mathematical or statistical method like a neural network, a large number of
simulation runs is
still needed. Simulation time for such a reservoir size is typically 1 hour
for a fast multi-CPU
workstation, so the simulation time needed is cost and/or time prohibitive.
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645 PCT/US2015/018319
System Description
[0032] The present disclosure may be implemented through a computer-executable
program of instructions, such as program modules, generally referred to as
software applications
or application programs executed by a computer. The software may include, for
example,
routines, programs, objects, components, data structures, etc,, that perform
particular tasks or
implement particular abstract data types. The software forms an interface to
allow a computer to
react according to a source of input. NeXUSTM, which is commercial software
application
marketed by Landmark Graphics Corporation, may be used as interface
application to
implement the present disclosure. The software may also cooperate with other
code segments to
initiate a variety of tasks in response to data received in conjunction with
the source of the
received data. Other code segments may provide optimization components
including, but not
limited to, neural networks, earth modeling, history-matching, optimization,
visualization, data
management, reservoir simulation and economics. The software may be stored
and/or carried
on any variety of memory such as CD-ROM, magnetic disk, bubble memory and
semiconductor
memory (e.g., various types of RAM or ROM). Furthermore, the software and its
results may
be transmitted over a variety of carrier media such as optical fiber, metallic
wire, and/or through
any of a variety of networks, such as the Internet.
[0033] Moreover, those skilled in the art will appreciate that the disclosure
may be
practiced with a variety of computer-system configurations, including hand-
held devices,
multiprocessor systems, microprocessor-based or programmable-consumer
electronics,
minicomputers, mainframe computers, and the like, Any number of computer-
systems and
computer networks are acceptable for use with the present disclosure. The
disclosure may be
11
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645 PCT/US2015/018319
practiced in distributed-computing environments where tasks are performed by
remote-
processing devices that are linked through a communications network. In a
distributed-
computing environment, program modules may be located in both local and remote
computer-
storage media including memory storage devices. The present disclosure may
therefore, be
implemented in connection with various hardware, software or a combination
thereof in a
computer system or other processing system.
[0034] Referring now to FIG. 4, a block diagram illustrates one embodiment of
a
system for implementing the present disclosure on a computer. The system
includes a
computing unit, sometimes referred to as a computing system, which contains
memory,
application programs, a client interface, a video interface, and a processing
unit. The computing
unit is only one example of a suitable computing environment and is not
intended to suggest any
limitation as to the scope of use or functionality of the disclosure.
[0035] The memory primarily stores the application programs, which may also be
described as program modules containing computer-executable instructions,
executed by the
computing unit for implementing the present disclosure described herein and
illustrated in
FIGS. 1-3. The memory therefore, includes a potential well location selection
module, which
enables each step in FIGS. 1A-1B. The potential well location selection module
may integrate
functionality from the remaining application programs illustrated in FIG. 4.
In particular,
Nexus TM may be used as an interface application to supply the reservoir grid
model used by the
method 100 in FIGS. 1A-1B. Although Nexus TM may be used as interface
application, other
interface applications may be used, instead, or the potential well location
selection module may
be used as a stand-alone application.
12
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645 PCT/US2015/018319
[0036] Although the computing unit is shown as having a generalized memory,
the
computing unit typically includes a variety of computer readable media. By way
of example,
and not limitation, computer readable media may comprise computer storage
media and
communication media. The computing system memory may include computer storage
media in
the form of volatile and/or nonvolatile memory such as a read only memory
(ROM) and random
access memory (RAM). A basic input/output system (BIOS), containing the basic
routines that
help to transfer information between elements within the computing unit, such
as during start-
up, is typically stored in ROM. The RAM typically contains data and/or program
modules that
are immediately accessible to and/or presently being operated on by the
processing unit. By
way of example, and not limitation, the computing unit includes an operating
system,
application programs, other program modules, and program data.
[0037] The components shown in the memory may also be included in other
removable/non-removable, volatile/nonvolatile computer storage media or they
may be
implemented in the computing unit through an application program interface
("API") or cloud
computing, which may reside on a separate computing unit connected through a
computer
system or network. For example only, a hard disk drive may read from or write
to non-
removable, nonvolatile magnetic media, a magnetic disk drive may read from or
write to a
removable, nonvolatile magnetic disk, and an optical disk drive may read from
or write to a
removable, nonvolatile optical disk such as a CD ROM or other optical media.
Other
removable/non-removable, volatile/nonvolatile computer storage media that can
be used in the
exemplary operating environment may include, but are not limited to, magnetic
tape cassettes,
flash memory cards, digital versatile disks, digital video tape, solid state
RAM, solid state ROM,
13
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645 PCT/US2015/018319
and the like, The drives and their associated computer storage media discussed
above provide
storage of computer readable instructions, data structures, program modules
and other data for
the computing unit.
[0038] A client may enter commands and information into the computing unit
through
the client interface, which may be input devices such as a keyboard and
pointing device,
commonly referred to as a mouse, trackball or touch pad. Input devices may
include a
microphone, joystick, satellite dish, scanner, voice recognition or gesture
recognition, or the
like. These and other input devices are often connected to the processing unit
through the client
interface that is coupled to a system bus, but may be connected by other
interface and bus
structures, such as a parallel port or a universal serial bus (USB).
[0039] A monitor or other type of display device may be connected to the
system bus
via an interface, such as a video interface. A graphical user interface
("GUI") may also be used
with the video interface to receive instructions from the client interface and
transmit instructions
to the processing unit. In addition to the monitor, computers may also include
other peripheral
output devices such as speakers and printer, which may be connected through an
output
peripheral interface.
[0040] Although many other internal components of the computing unit are not
shown,
those of ordinary skill in the art will appreciate that such components and
their interconnection
are well known.
[0041] While the present disclosure has been described in connection with
presently
preferred embodiments, it will be understood by those skilled in the art that
it is not intended to
limit the disclosure to those embodiments. It is therefore, contemplated that
various alternative
14
SUBSTITUTE SHEET (RULE 26)
CA 02975437 2017-07-31
WO 2016/140645 PCT/US2015/018319
embodiments and modifications may be made to the disclosed embodiments without
departing
from the spirit and scope of the disclosure defined by the appended claims and
equivalents
thereof.
SUBSTITUTE SHEET (RULE 26)
