CA-3038717-C - ENHANCED TWO POINT FLUX APPROXIMATION SCHEME FOR RESERVOIR SIMULATION

Abstract

A method for performing a modified two point flux approximation scheme is disclosed. The method includes: obtaining a first pressure value for a first neighbor cell and a second pressure value for a second neighbor cell, where the first neighbor cell has a first value of a reservoir property and the second neighbor cell as a second value of the reservoir property; determining a first weight using the first pressure value and a second weight using the second pressure value; calculating a third value of the reservoir property as a weighted average of the first value and the second value; and applying the third value to the first neighbor cell.

Inventors

• Tom Jonsthovel
• Terry Wayne Stone

Assignees

• SCHLUMBERGER CANADA LIMITED

Dates

Publication Date

20260505

Application Date

20170928

Priority Date

20160928

Claims (8)

1. CLAIMS: 1. A computer-implemented method for reservoir simulation, comprising: obtaining a reservoir model generated using a plurality of field measurements and a gridding operation that assigns the plurality of field measurements to a plurality of cells defined for 5 the reservoir model; iteratively executing simulation across multiple time steps, by: obtaining a first phase pressure value for a first neighbor cell and a second phase pressure value for a second neighbor cell at the current time step, wherein the first neighbor cell has a first value of a reservoir property and the second neighbor cell has a second value 10 of the reservoir property; determining whether a difference between the first phase pressure value and the second phase pressure value at the current time step falls within a range that is close to a value of zero difference between the first phase pressure value and the second phase pressure value, 15 if the determined difference falls within the range that is close to a value of zero, determining whether a fluid flow direction between the first neighbor cell and the second neighbor cell has changed since the iteration of the simulation at the preceding time step, if the fluid flow direction has changed, calculating a third value of the reservoir property using a weighted average of the first and second values of the reservoir property, 20 wherein the applied weights comprise the first phase pressure value and the second phase pressure value; and applying the third value to the first neighbor cell; and outputting the simulation results for use in performing an oilfield operation, wherein the oilfield operation includes one or more of a drilling operation or actuating an electrical or mechanical 25 device at a wellsite based on the simulation results.
2. 2. The method of claim 1, further comprising: applying the third value to the second neighbor cell. 85181489 31
3. 3. The method of claim 1, wherein if the determined difference does not fall within the range that is close to a value of zero, calculating reservoir property values for the current time step using a standard two point flux approximation.
4. 4. The method of claim 1 wherein the range of the difference between the first phase pressure value and the second phase pressure value 5 is 200kPa (2 bar).
5. 5. The method of claim 1 where the simulation is a thermal simulation comprising one of: heating of cells of the digital reservoir model; injection of steam in cells of the digital reservoir model; a cyclic steam simulation in cells of the digital reservoir model; 10 a steam drive in cells of the digital reservoir model; or a two-stage steam assisted gravity drainage system.
6. 6. The method of claim 1, wherein each simulation ends when equilibrium is reached.
7. 7. A non-transitory computer readable medium for simulation, comprising computer readable instructions which, when executed by a computer, cause the computer to perform the steps of any 15 one of claims 1 to 6.
8. 8. A computer system configured to perform the method of any one of claims 1 to 6, the computer system comprising: a data repository for storing a plurality of field measurements; and a computer processor; and 20 a simulator.

Description

[0001] [0002] [0003] [0004] ENHANCED TWO POINT FLUX APPROXIMATION SCHEME FOR RESERVOIR SIMULATION BACKGROUND Reservoir simulation involves solving a set of non-linear partial differential equations (PD Es) modeling the fluid flow in porous media over a set of time steps. In order to solve the PDEs, the equations are often discretized on a grid of cells. SUMMARY In general, one or more embodiments relate to a method for simulation. The method comprises: obtaining a reservoir model generated using a plurality of field measurements; executing a simulation using a modified two point flux approximation scheme; and outputting simulation results. In general, one or more embodiments relate to a method for performing a modified two point flux approximation scheme. The method comprises: obtaining a first pressure value for a first neighbor cell and a second pressure value for a second neighbor cell, wherein the first neighbor cell has a first value of a reservoir property and the second neighbor cell as a second value of the reservoir property; determining a first weight using the first pressure value and a second weight using the second pressure value; calculating a third value of the reservoir property as a weighted average of the first value and the second value; and applying the third value to the first neighbor cell. In general, one or more embodiments relate to a non-transitory computer readable medium for simulation. The computer readable medium comprises computer readable program code for: obtaining a reservoir model generated using a plurality of field measurements; executing a simulation using a 1 WO 2018/064366 PCT/0S2017/054072 modified two point flux approximation scheme; and outputting simulation results. [0005] In general, one or more embodiments relate to a non-transitory computer [0006] [0007] readable medium for performing a modified two point flux approximation scheme. The computer readable medium comprises computer readable program code for: obtaining a first pressure value for a first neighbor cell and a second pressure value for a second neighbor cell, wherein the first neighbor cell has a first value of a reservoir property and the second neighbor cell as a second value of the reservoir property; determining a first weight using the first pressure value and a second weight using the second pressure value; calculating a third value of the reservoir property as a weighted average of the first value and the second value; and applying the third value to the first neighbor cell. In general, one or more embodiments relate to a computer system for modified two point flux approximation. The computer system comprises: a data repository for storing a plurality of field measurements; a computer processor; and a simulator configured to: obtain a first pressure value for a first neighbor cell and a second pressure value for a second neighbor cell, wherein the first neighbor cell has a first value of a reservoir property and the second neighbor cell as a second value of the reservoir property; detennine a first weight using the first pressure value and a second weight using the second pressure value; calculate a third value of the reservoir property as a weighted average of the first value and the second value; and apply the third value to the first neighbor cell. BRIEF DESCRIPTION OF DRAWINGS FIGs. 1 and 2 shows system diagrams in accordance with one or more embodiments. 2 WO 2018/064366 PCT/0S2017/054072 [0008] [0009] [0010] [0011] [0012] [0013] [0014] FIGs. 3 and 4 show flowcharts m accordance with one or more embodiments. FIGs. 5, 6, 7, and 8 show examples in accordance with one or more embodiments. FIGs. 9.1 and 9.2 show a computing system in accordance with one or more embodiments. DETAILED DESCRIPTION Specific embodiments will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. In the following detailed description of embodiments, numerous specific details are set forth in order to provide a more thorough understanding. However, it will be apparent to one of ordinary skill in the art that embodiments may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description. Throughout the application, ordinal numbers ( e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being a single element unless expressly disclosed, such as by the use of the terms "before", "after", "single", and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and