A method and device for rapidly predicting reservoir pressure under two-phase seepage of multi-well interference

Abstract

This invention discloses a rapid method and equipment for predicting reservoir pressure in two-phase flow under multi-well interference, comprising the following steps: calculating the bottom-hole pressure rise increment of the injection well, calculating the formation pore pressure between wells, and calculating the inter-well pressure. This invention considers the low viscosity and high compressibility of near-well reservoir internally driven water, utilizes a dimensionless compressibility coefficient to eliminate the dependence of traditional analytical methods on the radius of human influence, and superimposes the influence of multi-well interference to construct an injection pressure prediction method for multi-well collaborative operations under geological sealing conditions, providing theoretical support for bottom-hole pressure prediction in deep saline aquifers.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide geological storage technology, specifically to a method and equipment for rapid prediction of reservoir pressure in two-phase flow under multi-well interference. Background Technology

[0002] In large scale In the process of geological sealing site selection and risk assessment, accurate prediction of bottomhole pressure is crucial for assessing caprock integrity, preventing rock fracturing, and preventing [other risks]. Leakage along the wellbore is of paramount importance. The key challenge is how to predict leaks quickly and with physical rigor without relying on massive numerical simulations. The accumulation and evolution of bottom hole pressure during injection into saline aquifers is a key technical bottleneck that urgently needs to be overcome to meet the real-time dynamic control requirements of engineering sites.

[0003] Current predictions of wellbore injection pressure primarily rely on high-precision numerical simulation methods capable of handling complex heterogeneous formations and multiphysics coupling problems. Conventional... Numerical modeling of storage sites involves millions of meshes, and a single simulation often takes hours or even days, making it difficult to meet the needs of dynamic adjustments based on real-time monitoring data in engineering projects. Secondly, numerical simulations place extremely high demands on computing hardware and the professional background of operators, hindering efficient application in actual production. In contrast, while existing analytical or semi-analytical formulas for wellbore pressure prediction offer the advantage of rapid calculation, they are limited by the complexity of the process. There are still serious deficiencies in characterizing the physical mechanisms of formation fluid storage. On the one hand, traditional analytical formulas often simplify formation fluids into single-phase flow, failing to fully consider the injection process. The two-phase displacement characteristics between water and saltwater. Ignoring Darcy's law and differences in fluid properties (such as viscosity and relative permeability) between the two phases leads to a lack of rigorous physical basis for predicting pressure accumulation patterns. On the other hand, large-scale... Sealing sites typically involve the coordinated operation of multiple wells. Existing analytical models often focus on the injection behavior of a single well, lacking consideration of the pressure superposition interference between adjacent acquisition and injection wells, making it difficult to accurately reproduce the distribution pattern of formation pore pressure in a multi-well system.

[0004] Therefore, in view of the above-mentioned technical problems, there is an urgent need to study a method and equipment for rapid prediction of reservoir pressure in two-phase flow under multi-well interference. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the existing technology by providing a method and device for rapid prediction of reservoir pressure in two-phase flow under multi-well interference.

[0006] The above-mentioned objectives of the present invention are achieved through the following technical means:

[0007] A rapid method for predicting reservoir pressure in two-phase flow under multi-well interference includes the following steps:

[0008] Calculate the incremental rise in bottom hole pressure of the injection well. :

[0009] ,

[0010] in, The reservoir pressure is dimensionless. For dimensionless time, Viscosity ratio for Injection time, The pressure propagation coefficient, The inertia coefficient,

[0011] Calculate the formation pore pressure between wells :

[0012] ,

[0013] in, The initial pressure of the reservoir. For the first Production from oral injection wells The viscosity is that of salt water. For reservoir permeability, Radial distance of the injection well Within the reservoir Distribution height; To set the radial oil supply distance, The distance between the collection well and the injection well. The number of injection and production wells,

[0014] Calculate inter-well pressure .

[0015] As mentioned above, dimensionless reservoir pressure Based on the following formula:

[0016] ,

[0017] in, For the maximum reservoir height, For reservoir density, For reservoir pressure, for Inject traffic, It is in the reservoir Viscosity.

[0018] As mentioned above, dimensionless time Based on the following formula:

[0019] ,

[0020] in, For reservoir porosity, The radius of the injection well. It is in the reservoir density.

[0021] As mentioned above, viscosity ratio Based on the following formula:

[0022] ,

[0023] in, It is the viscosity of salt water.

[0024] As mentioned above, pressure propagation coefficient Based on the following formula:

[0025] ,

[0026] in, The compressibility of the reservoir rock. The compressibility of the reservoir saline water.

[0027] As mentioned above, inertia coefficient Based on the following formula:

[0028] ,

[0029] in, Forchheimer parameters.

[0030] As mentioned above, the Forchheimer parameter is .

[0031] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the above-described method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference.

[0032] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method for rapid prediction of reservoir pressure in two-phase flow under multi-well interference.

[0033] A computer program product includes a computer program that, when executed by a processor, implements the steps of the above-described method for rapid prediction of reservoir pressure in two-phase flow under multi-well disturbance.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] By considering near-wellbore reservoir The low viscosity and high compressibility of water-displacing agents, utilizing dimensionless compressibility coefficients to eliminate the dependence of traditional analytical methods on the "radius of human influence," and superimposed with multi-well interference theory, thus constructing... Multi-well collaborative operation under geological sealing background Injection pressure prediction method. For deep saline aquifers. The prediction of injection well bottom pressure provides theoretical support. Attached Figure Description

[0036] Figure 1 a saline aquifer A schematic diagram of the physical model of a geological sealing well reservoir injection system;

[0037] Figure 2 This is a schematic diagram of the inter-well pressure distribution when the injection flow rate is 20t / d.

[0038] Figure 3 This is a schematic diagram of the pressure distribution between wells when the injection flow rate is 25 t / d. Detailed Implementation

[0039] To facilitate understanding and implementation of the present invention by those skilled in the art, the present invention will be further described in detail below with reference to specific examples. The implementation examples described herein are for illustration and explanation only and are not intended to limit the present invention.

[0040] Example 1:

[0041] saline layer Physical model of geological sealing well reservoir injection system, such as Figure 1 As shown, the physical model is a two-dimensional axisymmetric model, which includes the wellbore and the reservoir surrounding the wellbore. Figure 1 This is merely a schematic diagram of a portion of the structure bounded by the axis of the well shaft. Figure 1 In the middle, the injection well is located on the left side of the reservoir, and the radius of the injection well is... Maximum reservoir height is The right boundary of the reservoir is an infinite domain. When After entering the reservoir, due to the saline water and There is a significant density difference between the fluids, which is affected by buoyancy. Migration front migration within the reservoir exhibits overlap effects. When The transport distance is hour, The distribution height within the reservoir is .

[0042] A rapid method for predicting reservoir pressure in two-phase flow under multi-well interference includes the following steps:

[0043] Step S1: Obtain Inject traffic, Basic parameters such as injection time, saline water density, saline water viscosity, reservoir permeability, reservoir porosity, rock fracture pressure, formation fracture safety factor, number of injection wells, number of collection wells, and well spacing are included.

[0044] Step S2: Physical model construction.

[0045] Step S21: Based on the mass conservation equation and Darcy's law for two phases, establish a system containing... Two-phase flow physical models in saturated and saline regions

[0046] According to the mass conservation equation:

[0047] (1)

[0048] Among them, fluid flux With fluid flux satisfy:

[0049] ;

[0050] ; (2)

[0051] in, for Injection time, For reservoir porosity, This is the radial distance from the injection well. For reservoir permeability, Forchheimer parameters; It is in the reservoir density, For the maximum reservoir height, Radial distance from the injection well The reservoir height at that location, It is the density of salt water. It is in the reservoir Viscosity It's the viscosity of salt water. This refers to reservoir pressure. , for Inject traffic.

[0052] Increase the compressibility of reservoir rocks reservoir compression ratio Compressibility of reservoir saline water for:

[0053] ;

[0054] ;

[0055] ; (3)

[0056] in, To find the first-order partial derivative.

[0057] Substituting equations (2) and (3) into equation (1), we get:

[0058]

[0059] (4)

[0060] Step S22: Dimensionless Equation Reduction. The governing equations are simplified using dimensionless numbers, and the derivation is performed. The formula for bottom hole pressure accumulation under water-driven conditions, where the dimensionless parameters are expressed as follows.

[0061] dimensionless radius ;

[0062] Dimensionless time ;

[0063] Dimensionless flow ;

[0064] Dimensionless saline water flow ;

[0065] Dimensionless reservoir pressure ;

[0066] Dimensionless height ; (5)

[0067] Pressure propagation coefficient ;

[0068] coefficient of inertia ;

[0069] viscosity ratio ;

[0070] Dimensionless fluid compressibility ;

[0071] Dimensionless density .

[0072] Substituting the dimensionless numbers above into equations (2) and (4), we get:

[0073]

[0074] (6)

[0075]

[0076] (7)

[0077] Solving equations (6) and (7) simultaneously yields the increment of the bottom hole pressure in the injection well. for:

[0078] (8)

[0079] Step S33: Multi-well Cooperative Pressure Interference Superposition. When multiple injection and production wells are producing simultaneously in a formation, the production rate and spatial location parameters of the production wells are introduced, and the formation pore pressure between wells is obtained using the superposition principle. The calculation formula is:

[0080] (9)

[0081] in, —No. The production of the injection-production well, where the injection-production well is a production well, then " "Take a negative value, and the injection-production well is an injection well, then..." Take the positive value;

[0082] — Formation pore pressure, MPa;

[0083] —Initial reservoir pressure, MPa;

[0084] —Set the radial oil supply distance; in this embodiment, it is set to 100m.

[0085] —Distance between the collection well and the injection well (can also be set to a fixed value), m;

[0086] — Viscosity of saline water, Pa·s;

[0087] —Radial distance of injection well Within the reservoir Distribution height;

[0088] Therefore, the interwell pressure can be obtained from equation (6) + (7). Calculation formula:

[0089] (10)

[0090] Step S4: Injection Pressure Safety Assessment. Introduce a formation fracturing safety factor. Multiply the product of the set caprock breakthrough pressure and the formation fracturing safety factor, and the product of the set rock fracturing pressure and the formation fracturing safety factor, respectively, by the inter-well pressure. Perform real-time comparisons.

[0091] In this embodiment, the injection well is 1800 m deep, the wellbore radius is 0.1 m, and the distance between the injection well and the collection well is 200 m. The injection flow rates are 20t / d and 25t / d. The injection time is 600 days, and the reservoir permeability is 2×10⁻⁶. -15 m 2 The reservoir porosity is 0.1, and the formation fracturing safety factor is 0.85; the calculation results are as follows: Figure 2 , Figure 3 As shown in the figure, the injection bottom hole pressures were 28.8 MPa and 29.5 MPa. A comparison of the site logging data is shown in Table 1. Therefore, the calculation results of this method show a high degree of agreement with the engineering data, demonstrating strong potential for engineering applications.

[0092] Table 1 Comparison of Calculation Results and Site Monitoring Data

[0093]

[0094] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods.

[0095] Example 2:

[0096] In this embodiment, a computer device is also provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0097] Example 3:

[0098] In this embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps in the above-described method embodiments.

[0099] Example 4:

[0100] In this embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0101] It should be noted that the embodiments described in this invention are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described embodiments or use similar methods to substitute them, but without departing from the spirit of the invention or exceeding the scope defined by the invention.

Claims

1. A rapid method for predicting reservoir pressure in two-phase flow under multi-well interference, characterized in that, Includes the following steps: Calculate the incremental rise in bottom hole pressure of the injection well. : ， in, The reservoir pressure is dimensionless. For dimensionless time, Viscosity ratio for Injection time, The pressure propagation coefficient, The inertia coefficient, Calculate the formation pore pressure between wells : ， in, The initial pressure of the reservoir. For the first Production from oral injection wells The viscosity is that of salt water. For reservoir permeability, Radial distance of the injection well Within the reservoir Distribution height; To set the radial oil supply distance, The distance between the collection well and the injection well. The number of injection and production wells, Calculate inter-well pressure .

2. The method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in claim 1, characterized in that, The dimensionless reservoir pressure Based on the following formula: ， in, For the maximum reservoir height, For reservoir density, For reservoir pressure, for Inject traffic, It is in the reservoir Viscosity.

3. The method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in claim 2, characterized in that, The dimensionless time Based on the following formula: ， in, For reservoir porosity, The radius of the injection well. It is in the reservoir density.

4. The method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in claim 3, characterized in that, The viscosity ratio Based on the following formula: ， in, It is the viscosity of salt water.

5. The method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in claim 4, characterized in that, The pressure propagation coefficient Based on the following formula: ， in, The compressibility of the reservoir rock. The compressibility of the reservoir saline water.

6. The method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in claim 5, characterized in that, The coefficient of inertia Based on the following formula: ， in, Forchheimer parameters.

7. The method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in claim 6, characterized in that, The Forchheimer parameter is: .

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in any one of claims 1 to 7.

10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the steps of the method for rapid prediction of reservoir pressure under two-phase flow with multi-well interference as described in any one of claims 1 to 7.

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