Method, device, medium and equipment for obtaining effective compression coefficient of oil reservoir

Abstract

The present invention discloses a method, device, medium and equipment for obtaining the effective compression coefficient of an oil reservoir, which relates to the field of oil and gas field development. The method comprises obtaining production data, water injection data and physical parameters of a well; determining the cumulative water injection volume, oil pressure and daily oil production between the two rounds of water injection according to the production data and water injection data of the well; determining the ratio of the cumulative water injection volume and the oil pressure by linearly fitting the cumulative water injection volume and the oil pressure; obtaining the cumulative oil production between the two rounds of water injection in combination with the daily oil production between the two rounds of water injection, and determining the water-oil ratio after water injection; determining the volume of the oil reservoir after water injection based on the obtained physical parameters and the water-oil ratio; and accurately obtaining the effective compression coefficient of the oil reservoir after water injection by constructing a relationship between the volume of the oil reservoir after water injection and the original volume and reserves and the volume coefficient of the original crude oil, as well as a relationship between the volume of the oil reservoir after water injection and the material balance of the oil reservoir.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development, and in particular to a method, device, medium and equipment for obtaining an effective compression coefficient of an oil reservoir. Background Art

[0002] The calculation of dynamic reserves is an essential step in the development of oil reservoirs. The calculation of dynamic reserves is mainly based on the material balance equation theory, and the effective compressibility coefficient of the oil reservoir is an important parameter of the material balance equation. The effective compressibility coefficient of the oil reservoir is related to the physical properties of rocks, crude oil and formation water, and is also affected by temperature and pressure. Water injection is the process of injecting water into the oil reservoir to replace crude oil, thereby maintaining or increasing the oil layer pressure and increasing crude oil production. During the water injection process, the injection of water will increase the pore pressure, causing the rock skeleton to expand or compress, resulting in a change in the effective compressibility coefficient of the oil reservoir.

[0003] The calculation of the effective compressibility coefficient of conventional reservoirs only considers the volume changes of rock pores, irreducible water and formation water, but does not consider the impact of other factors on the effective compressibility coefficient of the reservoir after water injection. As a result, the accuracy of obtaining the effective compressibility coefficient of the reservoir after water injection is poor. Summary of the Invention

[0004] The present invention provides a method, device, medium and equipment for obtaining the effective compressibility coefficient of an oil reservoir, which is used to solve the above-mentioned problem existing in the prior art, namely, how to improve the accuracy of obtaining the effective compressibility coefficient of an oil reservoir after water injection in the prior art. The present invention provides a method for obtaining the effective compressibility coefficient of an oil reservoir, which comprises:

[0005] Obtain well production data, water injection data and physical property parameters;

[0006] Based on the well's production data and water injection data, the cumulative water injection volume, oil pressure, and daily oil production between the two water injection rounds are determined. By performing a linear fit between the cumulative water injection volume and oil pressure, the ratio of the cumulative water injection volume to the oil pressure is determined. Combined with the daily oil production between the two water injection rounds, the cumulative oil production between the two water injection rounds is obtained to determine the water-oil ratio after water injection.

[0007] Determine the volume change of the reservoir after water injection based on the obtained physical parameters and water-oil ratio;

[0008] Determine the volume of the reservoir after water injection based on the change in volume after water injection and the original volume of the reservoir;

[0009] The relationship between the reservoir volume after water injection and the original reservoir volume and reserves and the original crude oil volume coefficient is constructed, as well as the relationship between the reservoir volume after water injection and the reservoir material balance, to obtain the effective compression coefficient of the reservoir after water injection.

[0010] Optionally, determining the volume change of the reservoir after water injection based on the acquired physical properties and water-oil ratio specifically includes:

[0011] When the reservoir pressure drops from the original formation pressure to the current formation pressure, the pore volume of the reservoir will decrease. The pore volume reduction is obtained by the following formula:

[0012] ;

[0013] As the reservoir pressure drops from the original formation pressure to the current formation pressure, the volume of water, injected water, and irreducible water in the reservoir will expand. The following formula is used to calculate the irreducible water volume expansion:

[0014] ;

[0015] The water volume expansion is obtained using the following formula:

[0016] ;

[0017] After water injection, as the reservoir is produced, the reservoir pressure begins to drop and the volume of the injected water expands. The following formula is used to calculate the volume expansion of the injected water:

[0018] ;

[0019] Defining the water-oil ratio R wo The volume of water in the reservoir or connected to it V w and oil-bearing reservoir volume V o The ratio is expressed as:

[0020] ;

[0021] The relationship between pore volume, original reservoir volume and irreducible water saturation is:

[0022] ;

[0023] Based on the pore volume reduction, irreducible water volume expansion, water volume expansion, and injected water volume expansion, combined with the defined water-oil ratio and the relationship between the void volume, original reservoir volume, and irreducible water saturation, the change in reservoir volume after water injection is calculated using the following formula:

[0024] ;

[0025] make

[0026] ;

[0027] The change in reservoir volume after water injection is:

[0028] ;

[0029] Among them, Δ V p Pore volume reduction, V w is the volume of water in the reservoir or connected to it, Δ V WC is the volume expansion of bound water, V WC is the volume of bound water, Δ V W is the volume expansion of the water body, V WC is the volume of water, Δ V inj is the volume expansion of injected water, V o is the volume of oil-bearing reservoir, C p is the compression coefficient of rock, C w is the compressibility coefficient of formation water, S wc is the irreducible water saturation, Δp is the pressure drop, R wo is the water-oil ratio after water injection, B w is the volume coefficient of formation water, V p is the pore volume, V inj is the cumulative water injection volume, V ci is the original reservoir volume, C c is the reservoir volume compressibility factor considering the water-oil ratio.

[0030] Optionally, determining the volume of the reservoir after water injection based on the volume change of the reservoir after water injection in combination with the original reservoir volume specifically includes:

[0031] The reservoir volume after water injection is equal to the original reservoir volume minus the reservoir volume change, which can be expressed as follows:

[0032] ;

[0033] The following formula is used to obtain the reservoir volume after water injection:

[0034] ;

[0035] in, V c is the reservoir volume after water injection,V ci is the original reservoir volume, Δ V is the change in reservoir volume, Δp is the pressure drop, B w is the volume coefficient of formation water, V inj is the cumulative water injection volume, C p is the compression coefficient of rock, C w is the compressibility coefficient of formation water, C c is the reservoir volume compressibility factor considering the water-oil ratio.

[0036] Optionally, the relationship between the original reservoir volume and reserves and the original crude oil volume coefficient specifically includes:

[0037] ;

[0038] in, N For reserves, B oi is the volume coefficient of the original crude oil, V ci is the original reservoir volume.

[0039] Optionally, the relationship between the reservoir volume after water injection and the reservoir material balance specifically includes:

[0040] ;

[0041] in, N For reserves, N p is the cumulative oil production, V c is the reservoir volume after water injection, B o is the volume coefficient of crude oil.

[0042] Optionally, obtaining the effective compressibility coefficient of the reservoir after water injection specifically includes:

[0043] ;

[0044] in, C c is the reservoir volume compressibility factor considering the water-oil ratio, C p is the rock compression coefficient, C w is the compressibility coefficient of formation water, Δp is the pressure drop, B w is the volume coefficient of formation water, V injis the cumulative water injection volume, Δp is the pressure drop, N p is the cumulative oil production, B o is the volume coefficient of crude oil, C o is the compressibility coefficient of crude oil.

[0045] Also includes:

[0046] The dynamic reserves are determined based on the flow material balance equation, and the flow material balance production indicator curve is used to verify the effective compressibility of the reservoir after water injection.

[0047] Optionally, determining the dynamic reserves according to the flow material balance equation specifically includes:

[0048] ;

[0049] in, t c To balance the time, t c =( N p B o + W p B w ) / q; N is the dynamic reserve, b pss is the coefficient under quasi-stable flow state, Δp is the pressure drop, B oi is the volume coefficient of the original crude oil, q is the daily liquid production, C e is the effective compression coefficient of the reservoir after water injection to replace oil, N p is the cumulative oil production, B o is the volume coefficient of crude oil, W p is the cumulative water production, B w is the volume coefficient of formation water.

[0050] The present invention provides a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the method for obtaining the effective compressibility coefficient of an oil reservoir is implemented.

[0051] The present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the method for obtaining the effective compressibility coefficient of an oil reservoir is implemented.

[0052] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a method for obtaining the effective compression coefficient of an oil reservoir, which takes into account the influence of injected water on the effective compression coefficient of an oil reservoir on the basis of a conventional calculation formula for the effective compression coefficient of an oil reservoir, and obtains the cumulative water injection volume, oil pressure and cumulative oil production of the well according to the production data and water injection data of the well, and obtains the water-oil ratio by linearly fitting the cumulative water injection volume and oil pressure of the well, and obtains a more accurate effective compression coefficient of the oil reservoir after water injection by taking into account the volume of the injected water and the volume change of the oil reservoir volume after water injection; in actual production, water injection is used to increase formation energy, and the injected water for replacing oil with water will increase the pore pressure, causing the rock skeleton to expand or compress, so that the effective compression coefficient of the oil reservoir changes accordingly. Compared with the oil reservoir compression coefficient without considering water injection, the present invention can obtain a more realistic effective compression coefficient of the oil reservoir after water injection, thereby effectively improving the accuracy of obtaining the effective compression coefficient of the oil reservoir after water injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0054] Figure 1 A flow chart of a method for obtaining an effective compressibility coefficient of an oil reservoir provided by an embodiment of the present invention;

[0055] Figure 2 A technical roadmap for calculating the effective compressibility of an oil reservoir provided by an embodiment of the present invention;

[0056] Figure 3 A relationship diagram between the cumulative water volume and oil pressure in the first round of water injection provided by an embodiment of the present invention;

[0057] Figure 4 A relationship diagram between the cumulative water volume and oil pressure in the second round of water injection provided by an embodiment of the present invention;

[0058] Figure 5 A relationship diagram between the cumulative water injection volume and oil pressure in the third round of water injection provided by an embodiment of the present invention;

[0059] Figure 6 A relationship diagram between the cumulative water injection volume and oil pressure in the fourth round of water injection provided by an embodiment of the present invention;

[0060] Figure 7 This is a production indicator curve diagram of the flowing material balance method for Well A provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0062] The following describes in detail the technical solution of the present invention and how the technical solution of the present invention solves the above-mentioned technical problems using specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The following embodiments of the present invention are described in conjunction with the accompanying drawings.

[0063] Example 1

[0064] like Figure 1 and Figure 2 As shown, this embodiment shows a method for obtaining an effective compressibility coefficient of an oil reservoir, comprising:

[0065] S1: Obtain well production data, water injection data, and physical property parameters.

[0066] For example, the physical property parameters may include the crude oil compressibility coefficient C o , crude oil volume coefficient B o , rock compression coefficient C p and formation water compressibility C w .

[0067] For example, an empirical formula of the formation water compressibility coefficient can be obtained based on the test data of the block, so as to calculate the formation water compressibility coefficient. The empirical formula of the formation water compressibility coefficient is:

[0068] ;

[0069] in,

[0070] ;

[0071] in, T is the formation temperature, P R is the formation pressure, R sw is the solubility of natural gas in formation water, C w is the formation water compressibility coefficient.

[0072] In this embodiment,T You can take 152°C, P R Take 105MPa, R sw Take 2m 3 / m 3 , according to the above empirical formula, calculate the formation water compressibility coefficient C w is 6.729×10 -4 MPa -1 .

[0073] For example, the crude oil compressibility coefficient is obtained based on PVT data and rock compressibility test results. C o and rock compressibility C p , the crude oil compressibility coefficient can be taken as C o is 47.33×10 -4 MPa -1 , rock compressibility C p 0.66×10 -4 MPa -1 .

[0074] S2: Based on the production data and water injection data of the well, determine the cumulative water injection volume, oil pressure, and daily oil production between the two water injection rounds. By performing a linear fit between the cumulative water injection volume and oil pressure, determine the ratio of the cumulative water injection volume and oil pressure. Combined with the daily oil production between the two water injection rounds, obtain the cumulative oil production between the two water injection rounds and determine the water-oil ratio after water injection.

[0075] For example, based on the water injection data, the cumulative water injection volume and oil pressure of each round of water injection are obtained, and the relationship between the cumulative water injection volume and the oil pressure is plotted with the cumulative water injection volume as the x value and the oil pressure as the y value, such as Figures 3 to 6 As shown, perform linear fitting to obtain the slope of the straight line segment of the relationship diagram between the water injection volume and oil pressure in this round and the next round K 1 and K 2. Then, based on the production dynamic data, obtain the daily oil production for multiple days between the two rounds of water injection and calculate the cumulative oil production between the two rounds of water injection Δ V o (m 3 ).

[0076] Optionally, the water-oil ratio after water injection can be obtained using the following formula:

[0077] ;

[0078] in, B wis the volume coefficient of formation water, C w is the compressibility coefficient of formation water, Δ V o is the cumulative oil production, R wo is the water-oil ratio after water injection, K 1 is the slope of the straight line segment between the cumulative water injection volume and the oil pressure of this round, K 2 is the slope of the straight line segment between the cumulative water injection volume and oil pressure of the lower wheel, B o is the volume coefficient of crude oil.

[0079] In this embodiment, the volume coefficient of formation water is B w The crude oil volume coefficient is 1.02. B o is 1.5831, as shown in Table 1, showing the water-oil ratio of Well A after each round of water injection. R wo .

[0080] Table 1 Water-oil ratio after each water injection round in Well A R wo

[0081]

[0082] S3: Determine the volume change of the reservoir after water injection based on the obtained physical properties and water-oil ratio.

[0083] S4: Determine the volume of the reservoir after water injection based on the change in the reservoir volume after water injection and the original reservoir volume.

[0084] S5: Construct the relationship between the reservoir volume after water injection and the original reservoir volume and reserves and the original crude oil volume coefficient, as well as the relationship between the reservoir volume after water injection and the reservoir material balance, to obtain the effective compression coefficient of the reservoir after water injection.

[0085] The following is a detailed description of the process of obtaining the effective compressibility coefficient of the reservoir after water injection.

[0086] For example, after water injection, the reservoir pressure drops from the original formation pressure to the current formation pressure, and the pore volume of the reservoir decreases, that is, the pore volume decreases by Δ V P for:

[0087] ;

[0088] in, V p is the pore volume, V wis the volume of water in the reservoir or connected to it, V inj is the cumulative water injection volume, C p is the compression coefficient of rock, and Δp is the pressure drop.

[0089] The reservoir pressure drops from the original formation pressure to the current formation pressure, and the volume of water, injected water, and bound water in the reservoir expands;

[0090] Bound water volume expansion Δ V WC for:

[0091] ;

[0092] in, V WC is the volume of bound water, C w is the compressibility coefficient of formation water.

[0093] Water volume expansion Δ V W for:

[0094] ;

[0095] After water injection, as the reservoir is produced, the reservoir pressure begins to drop and the volume of injected water expands, that is, the volume expansion of injected water Δ V inj for:

[0096] ;

[0097] in, B w is the volume coefficient of formation water.

[0098] The pore volume of the reservoir will decrease, and the volume of water, injected water, and bound water in the reservoir will expand, resulting in a decrease in the reservoir volume. That is, the change in the reservoir volume is:

[0099] ;

[0100] in, S wc is the bound water saturation.

[0101] By increasing the water-oil ratio R wo Defined as the volume of water in or connected to the reservoir V w and oil-bearing reservoir volume V o The specific calculation formula is as follows:

[0102] ;

[0103] Based on the above-calculated pore volume reduction, bound water volume expansion, water volume expansion, injected water volume expansion, and the defined water-oil ratio, the change in reservoir volume can be obtained:

[0104] ;

[0105] in, C p is the compression coefficient of rock, C w is the compressibility coefficient of formation water, S wc is the irreducible water saturation, Δp is the pressure drop, R wo is the water-oil ratio after water injection, B w is the volume coefficient of formation water, V p is the pore volume, V inj is the cumulative water injection volume.

[0106] There is also a relationship between pore volume, original reservoir volume and irreducible water saturation:

[0107] ;

[0108] in, V p is the pore volume, V ci is the original reservoir volume.

[0109] Substituting the relationship between pore volume, original reservoir volume, and irreducible water saturation into the reservoir volume change after adjustment including the water-oil ratio, we can obtain:

[0110] ;

[0111] In order to facilitate the derivation of the subsequent reservoir effective compressibility formula, the reservoir volume compressibility factor considering the water-oil ratio is introduced. C c , the expression is as follows:

[0112] ;

[0113] in, C p is the compression coefficient of rock, C w is the compressibility coefficient of formation water, S wcis the irreducible water saturation, Δp is the pressure drop, R wo is the water-oil ratio after water injection.

[0114] The change in reservoir volume after water injection is:

[0115] ;

[0116] The reservoir volume will change after water injection. The reservoir volume after water injection is equal to the original reservoir volume minus the reservoir volume change. The specific calculation formula is as follows:

[0117] ;

[0118] Then the reservoir volume after water injection can be obtained V c for:

[0119] ;

[0120] According to reservoir engineering theory, the original reservoir and reserves can be obtained N and the original crude oil volume coefficient B oi The relationship:

[0121] ;

[0122] in, N For reserves, B oi is the volume coefficient of the original crude oil, V ci is the original reservoir volume.

[0123] From the basic form of reservoir material balance, we can get:

[0124] ;

[0125] in, N For reserves, N p is the cumulative oil production, V c is the reservoir volume after water injection, B o is the volume coefficient of crude oil.

[0126] Arranged:

[0127] ;

[0128] According to the relationship between the crude oil compressibility coefficient, the original crude oil volume coefficient, the current crude oil volume coefficient and the pressure drop, the specific calculation process is as follows:

[0129] ;

[0130] According to the elastic material balance equation:

[0131] ;

[0132] Arranged:

[0133] ;

[0134] Eliminating the pressure drop Δp on both sides, we can get:

[0135] ;

[0136] The final effective compression coefficient of the reservoir after water injection is:

[0137] ;

[0138] in, C c is the reservoir volume compressibility factor considering the water-oil ratio, C p is the rock compression coefficient, C w is the compressibility coefficient of formation water, Δp is the pressure drop, B w is the volume coefficient of formation water, V inj is the cumulative water injection volume, Δp is the pressure drop, N p is the cumulative oil production, B o is the volume coefficient of crude oil, C o is the compressibility coefficient of crude oil.

[0139] Effective compressibility of reservoir after water injection C e As shown in Table 2:

[0140] Table 2 Effective compression coefficient of Well A after each round of water injection C e

[0141]

[0142] According to the effective compression coefficient after three rounds of water injection in Table 2, the average effective compression coefficient of the reservoir after three water injections can be obtained:

[0143] .

[0144] Example 2

[0145] This embodiment compares the effective compression coefficient of the reservoir with water injection and the compression coefficient of the reservoir without water injection, and determines the accuracy of the obtained effective compression coefficient of the reservoir with water injection in combination with actual conditions.

[0146] For example, the effective compressibility coefficient of the reservoir without water injection is calculated using the calculation formula of the effective compressibility coefficient of the reservoir without water injection:

[0147] ;

[0148] in, C eff is the effective compressibility coefficient of the reservoir without considering water injection.

[0149] The specific calculation formula for dynamic reserves based on the flow material balance equation is as follows:

[0150] ;

[0151] in, t c To balance the time, N is the dynamic reserve, b pss is the coefficient under the quasi-stable flow state, Δp is the pressure drop, B oi is the volume coefficient of the original crude oil, which can be 1.9792, and q is the daily liquid production. C e is the effective compressibility coefficient of the reservoir after water injection, which can be taken as 81.56×10 -4 MPa -1 .

[0152] Exemplary, equilibration time t c The expression can be ( N p B o + W p B w ) / q , where N p is the cumulative oil production, B o is the volume coefficient of crude oil, W p is the cumulative water production, B w is the volume coefficient of formation water.

[0153] According to the production dynamic data of well A, the oil production, water production and oil pressure of well A are obtained. t cis the X value, Δp / q is the Y value, and the flow material balance production indicator curve is drawn, such as Figure 7 As shown, the slope of the straight line segment is obtained K , whose slope K The expression is:

[0154] ;

[0155] According to the flow material balance production indicator curve of Well A, the slope of the straight line segment is K =0.0042, calculate the dynamic reserves of Well A N for:

[0156] ;

[0157] Without considering the effect of water injection on the effective compressibility of the reservoir, the dynamic reserves N of Well A is calculated as:

[0158] ;

[0159] The static geological model reserves of Well A obtained from the data provided by the oilfield unit are 1.3564×10 4 Comparing the two dynamic reserve calculation results, we find that the dynamic reserve error when considering the effect of water injection is 11.39%, while the dynamic reserve error when excluding water injection is 80.40%. This indicates that the reservoir effective compressibility calculated by this method is closer to reality and has a smaller dynamic reserve error.

[0160] By comparing the effective compression coefficient of the reservoir with and without water injection, it is found that water injection increases the effective compression coefficient of the reservoir of this well. The reason is that water injection causes the reservoir skeleton to be shear-expanded, resulting in an increase in the effective compression coefficient of the reservoir. The calculated result is more in line with the actual situation.

[0161] Conventional calculations of reservoir effective compressibility only consider changes in the volume of rock pores, bound water, and formation water. However, in actual production, water injection is used to increase formation energy. The injected water, used to displace oil, increases pore pressure, causing the rock skeleton to expand or compress, and consequently changes the reservoir's effective compressibility. Conventional calculations of reservoir effective compressibility are based on material balance equations, which are universal and applicable to any complex reservoir. This method, based on conventional calculations of reservoir effective compressibility, incorporates the influence of injected water on the reservoir's effective compressibility, thereby deriving the reservoir's effective compressibility after water injection. This method effectively improves the accuracy of reservoir effective compressibility and aligns it more closely with production practice.

[0162] The above is a method for obtaining the effective compressibility coefficient of an oil reservoir provided in one or more embodiments of this specification. Based on the same idea, this specification also provides a corresponding device for obtaining the effective compressibility coefficient of an oil reservoir, including:

[0163] Acquisition module, used to obtain well production data, water injection data and physical property parameters;

[0164] The water-oil ratio determination module is used to determine the cumulative water injection volume, oil pressure, and daily oil production between two water injection rounds based on the well's production data and water injection data. By performing a linear fit between the cumulative water injection volume and oil pressure, the ratio of the cumulative water injection volume and oil pressure is determined. Combined with the daily oil production between the two water injection rounds, the cumulative oil production between the two water injection rounds is obtained to determine the water-oil ratio after water injection;

[0165] A module for determining the volume change of the oil reservoir after water injection, which is used to determine the volume change of the oil reservoir after water injection based on the acquired physical parameters and water-oil ratio;

[0166] The post-water injection reservoir volume module is used to determine the post-water injection reservoir volume based on the change in the post-water injection reservoir volume and the original reservoir volume;

[0167] The module for determining the effective compression coefficient of the reservoir after water injection is used to construct the relationship between the reservoir volume after water injection and the original reservoir volume and reserves and the original crude oil volume coefficient, as well as the relationship between the reservoir volume after water injection and the reservoir material balance, to obtain the effective compression coefficient of the reservoir after water injection.

[0168] The specific definitions of the reservoir effective compressibility coefficient obtaining device can be found in the definitions of the reservoir effective compressibility coefficient obtaining method described above and will not be further elaborated here. Each module in the reservoir effective compressibility coefficient obtaining device described above can be implemented in whole or in part via software, hardware, or a combination thereof. Each of these modules can be embedded in or independent of a processor within a computer device in hardware form, or stored in a computer device memory in software form, allowing the processor to call and execute the corresponding operations of each module.

[0169] The present invention also provides a computer-readable storage medium, which stores a computer program. The computer program can be used to execute the above-mentioned method for obtaining the effective compressibility coefficient of the oil reservoir.

[0170] The present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for obtaining the effective compression coefficient of an oil reservoir when executing the program.

[0171] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

Claims

1. A method for obtaining an effective compressibility coefficient of an oil reservoir, characterized in that: include: Obtain well production data, water injection data and physical property parameters; Based on the well's production data and water injection data, the cumulative water injection volume, oil pressure, and daily oil production between the two water injection rounds are determined. By performing a linear fit between the cumulative water injection volume and oil pressure, the ratio of the cumulative water injection volume to the oil pressure is determined. Combined with the daily oil production between the two water injection rounds, the cumulative oil production between the two water injection rounds is obtained to determine the water-oil ratio after water injection. Determine the volume change of the reservoir after water injection based on the obtained physical parameters and water-oil ratio; The method of determining the volume change of the reservoir after water injection based on the obtained physical parameters and water-oil ratio specifically includes: When the reservoir pressure drops from the original formation pressure to the current formation pressure, the pore volume of the reservoir will decrease. The pore volume reduction is obtained by the following formula: ； As the reservoir pressure drops from the original formation pressure to the current formation pressure, the volume of water, injected water, and irreducible water in the reservoir will expand. The following formula is used to calculate the irreducible water volume expansion: ； The water volume expansion is obtained using the following formula: ； After water injection, as the reservoir is produced, the reservoir pressure begins to drop and the volume of the injected water expands. The following formula is used to calculate the volume expansion of the injected water: ； The water-oil ratio is defined as the ratio of the volume of water in the reservoir or the water body connected to it to the volume of the oil-bearing reservoir. The expression is: ； The relationship between pore volume, original reservoir volume and irreducible water saturation is: ； Based on the pore volume reduction, irreducible water volume expansion, water volume expansion, and injected water volume expansion, combined with the defined water-oil ratio and the relationship between pore volume, original reservoir volume, and irreducible water saturation, the change in reservoir volume after water injection is calculated using the following formula: ； make ； The change in reservoir volume after water injection is: ； Among them, Δ V p Pore volume reduction, V w is the volume of water in the reservoir or connected to it, Δ V WC is the volume expansion of bound water, V WC is the volume of bound water, Δ V W is the volume expansion of the water body, V WC is the volume of water, Δ V inj is the volume expansion of injected water, V o is the volume of oil-bearing reservoir, C p is the compression coefficient of rock, C w is the compressibility coefficient of formation water, S wc is the irreducible water saturation, Δp is the pressure drop, R wo is the water-oil ratio after water injection, B w is the volume coefficient of formation water, V p is the pore volume, V inj is the cumulative water injection volume, V ci is the original reservoir volume, C c is the reservoir volume compressibility factor considering the water-oil ratio; Determine the volume of the reservoir after water injection based on the change in volume after water injection and the original volume of the reservoir; Construct the relationship between the reservoir volume after water injection and the original reservoir volume and reserves and the original crude oil volume coefficient, as well as the relationship between the reservoir volume after water injection and the reservoir material balance, and obtain the effective compressibility coefficient of the reservoir after water injection; The obtaining of the effective compressibility coefficient of the oil reservoir after water injection specifically includes: ; in, N p is the cumulative oil production, B o is the volume coefficient of crude oil, C o is the compressibility coefficient of crude oil.

2. The method for obtaining the effective compressibility coefficient of an oil reservoir according to claim 1, wherein: The determination of the volume of the reservoir after water injection based on the volume change of the reservoir after water injection and the original reservoir volume specifically includes: The reservoir volume after water injection is equal to the original reservoir volume minus the reservoir volume change, which can be expressed as follows: ； The following formula is used to obtain the reservoir volume after water injection: ； in, V c is the reservoir volume after water injection, V ci is the original reservoir volume, Δ V is the change in reservoir volume, Δp is the pressure drop, B w is the volume coefficient of formation water, V inj is the cumulative water injection volume, C p is the compression coefficient of rock, C w is the compressibility coefficient of formation water, C c is the reservoir volume compressibility factor considering the water-oil ratio.

3. The method for obtaining the effective compressibility coefficient of an oil reservoir according to claim 1, wherein: The relationship between the original reservoir volume and reserves and the original crude oil volume coefficient specifically includes: ； in, N For reserves, B oi is the volume coefficient of the original crude oil, V ci is the original reservoir volume.

4. The method for obtaining the effective compressibility coefficient of an oil reservoir according to claim 1, wherein: The relationship between the reservoir volume after water injection and the reservoir material balance specifically includes: ； in, N For reserves, N p is the cumulative oil production, V c is the reservoir volume after water injection, B o is the volume coefficient of crude oil.

5. The method for obtaining the effective compressibility coefficient of an oil reservoir according to claim 1, wherein: The method further comprises: The dynamic reserves are determined based on the flow material balance equation, and the flow material balance production indicator curve is used to verify the effective compressibility of the reservoir after water injection.

6. The method for obtaining the effective compressibility coefficient of an oil reservoir according to claim 5, characterized in that: Determining the dynamic reserves according to the flow material balance equation specifically includes: ； in, t c To balance the time, t c =( N p B o + W p B w ) / q; N is the dynamic reserve, b pss is the coefficient under quasi-stable flow state, Δp is the pressure drop, B oi is the volume coefficient of the original crude oil, q is the daily oil production, C e is the effective compression coefficient of the reservoir after water injection to replace oil, N p is the cumulative oil production, B o is the volume coefficient of crude oil, W p is the cumulative water production, B w is the volume coefficient of formation water.

7. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and when the computer program is executed by a processor, the method for obtaining the effective compressibility coefficient of the oil reservoir according to any one of claims 1 to 6 is implemented.

8. A computer device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for obtaining the effective compressibility coefficient of the oil reservoir according to any one of claims 1 to 6 is implemented.

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