Investment cost partitioning method for multi-layered tight sandstone gas reservoirs

Abstract

This invention discloses a method for allocating investment costs in multi-layered tight sandstone gas reservoirs. By collecting data from the blocks to be evaluated, establishing the relationship between gas testing data and storage coefficients, and correcting the storage coefficients, the gas production contribution rate of each layer is calculated based on the corrected storage coefficients. The investment costs of shared facilities across the multi-layered reservoirs are then allocated based on these contribution rates. This invention solves the problems of existing methods, such as uneconomical evaluation of single layers leading to reserve loss, and the inability to calculate investment costs based on gas production profile data due to insufficient data.

Description

Technical Field

[0001] This invention belongs to the technical field of cost allocation methods for petroleum exploration and development, specifically relating to a method for allocating investment costs in multi-layered tight sandstone gas reservoirs. Background Technology

[0002] In the development of tight sandstone gas reservoirs, especially those with multiple gas-bearing strata, a multi-layered synergistic development approach is often adopted. However, when submitting reserve estimates, they are generally submitted as single layers. These multi-layered synergistic gas reservoirs typically employ shared facilities (drilling and surface facilities) across multiple layers. Therefore, when evaluating the reserves of a single layer, it is necessary to reasonably allocate the investment costs of the shared facilities (drilling and surface facilities).

[0003] The "QSY 01180-2020 Standard for Evaluation of Economically Recoverable Reserves of Oil and Gas" stipulates that "for special cases such as shared facilities (drilling and surface facilities), the economic evaluation can be carried out by allocating investment costs according to the actual situation, and the allocating principles and methods are provided." However, the standard does not provide a specific method for allocating investment costs.

[0004] In practice, the commonly used method is to segment reservoirs based on their thickness, which is simple and quick to implement. However, for tight sandstone gas reservoirs, the thickness of different gas-bearing strata often varies significantly, and the gas production capacity of a reservoir is not necessarily well correlated with its thickness. Simply segmenting based on reservoir thickness can lead to lower-productivity layers incurring higher investment costs, resulting in uneconomical evaluation of individual layers and loss of reserves. When gas production profile data is available, segmentation can also be performed using gas production profile testing data. This method is convenient to use, can accurately reflect the gas production capacity of the reservoir, and yields more reasonable results. However, during the exploration phase, gas production profile testing data is scarce, and during the development phase, limitations imposed by wellbore tubing make it difficult to comprehensively cover all test layers. Summary of the Invention

[0005] The purpose of this invention is to provide a method for allocating investment costs for multi-layered tight sandstone gas reservoirs. This method solves the problems of existing methods being uneconomical in evaluating single layers, resulting in the loss of reserves, and being unable to calculate investment costs based on gas production profile data due to a lack of data.

[0006] The technical solution adopted in this invention is: a method for allocating investment costs in multi-layered tight sandstone gas reservoirs. This method involves collecting data from the blocks to be evaluated, establishing the relationship between gas testing data and energy storage coefficients, correcting the energy storage coefficients, calculating the gas production contribution rate of each layer based on the corrected energy storage coefficients, and allocating the investment costs of multi-layered shared facilities based on the gas production contribution rate.

[0007] The technical solution adopted in this invention is also characterized by:

[0008] Furthermore, the method for allocating investment costs for multi-layered tight sandstone gas reservoirs is implemented according to the following steps:

[0009] Step 1: Collect production data for each layer of the wellhead in the block to be evaluated, the total investment cost M of the shared facilities, and the energy storage coefficient of each layer. data;

[0010] Step 2: Calculate the unobstructed flow rate Q for each layer using the wellhead production data collected in Step 1. n ;

[0011] Step 3, by calculating the unobstructed flow rate Q in Step 2 n With the energy storage coefficient collected in step 1 Fitting analysis was performed to establish the unobstructed flow rate Q for each layer. n With energy storage coefficient The fitting relationship is given by the coefficients of the fitting relationship, which represent the unit energy storage capacity A of each layer. n ;

[0012] Step 4: Calculate the unit energy storage capacity A for each layer as determined in Step 3. n Standardization is performed to obtain the standardized unit energy storage capacity of each layer.

[0013] Step 5: Use the standardized unit energy storage capacity obtained in Step 4 to obtain the energy production capacity of each layer. and the energy storage coefficient of each layer Calculate the corrected energy storage coefficient K for each layer n ;

[0014] Step 6: Utilize the corrected energy storage coefficients K obtained in Step 5 for each layer. n Calculate the gas production contribution rate G of each layer n ;

[0015] Step 7, based on the gas production contribution rate G of each layer calculated in Step 6 n The total investment cost M of shared facilities is divided into single-layer investment costs m. n .

[0016] Furthermore, the wellhead production data in step 1 includes the single-layer gas production q. n and oil pressure P T .

[0017] Furthermore, in step 2, the "one-point method" is used to calculate the unobstructed flow rate Q. n Specifically, calculate according to formula (1):

[0018]

[0019] Among them: Q n Single-layer unobstructed flow rate, q nSingle-layer gas production, P T Hydraulic pressure.

[0020] Furthermore, in step 3, the unobstructed flow rate Qn and the energy storage coefficient... Linear regression analysis was performed to establish a linear regression equation between the unobstructed flow rate and the energy storage coefficient, as shown in formula (2):

[0021]

[0022] Among them, A n The unit energy storage coefficient capacity of each layer.

[0023] Furthermore, in step 4, the linear scaling method is used to calculate the unit energy storage capacity A of each layer. n The standardization process is performed, as shown in formula (3):

[0024]

[0025] in, For A n Dimensionless data, i.e., the standardized unit energy storage capacity of each layer, A n A represents the unit energy storage capacity of each layer. min This represents the minimum energy storage coefficient capacity per unit of each layer; the minimum value for dimensionless data is 1.

[0026] Furthermore, the corrected energy storage coefficient K in step 5 n Calculated using formula (4):

[0027]

[0028] Among them, K n The corrected energy storage coefficients for each layer.

[0029] Furthermore, the gas production contribution rate G of each layer in step 6 n Calculated using formula (5):

[0030]

[0031] Where K1, K2, ..., K n The corrected energy storage coefficients for each layer.

[0032] Furthermore, step 7, single-layer investment cost m n Calculated using formula (6):

[0033] m n =G n ×M (6)

[0034] Where, m n For single-layer investment costs, G nM represents the gas production contribution rate of each floor, and M represents the total investment cost of shared facilities.

[0035] The beneficial effects of this invention are:

[0036] The investment cost allocation method for multi-layered tight sandstone gas reservoirs of this invention can effectively solve the problems of uneconomical evaluation of a single layer when allocating investment costs based on reservoir thickness, resulting in loss of reserves, and the inability to calculate investment costs when allocating investment costs based on gas production profile data due to lack of data.

[0037] This invention presents a method for allocating investment costs for multi-layered tight sandstone gas reservoirs. By establishing a relationship between gas testing data and the storage coefficient, the storage coefficient is corrected, and the gas production contribution rate of each layer is calculated based on the corrected storage coefficient. The gas production contribution rate effectively reflects the relative gas production capacity of each layer. Using this contribution rate as a basis, a reasonable allocation of investment costs for shared facilities (drilling and surface facilities) is achieved. This cost allocation method can achieve results approximately equivalent to those obtained from gas production profiles, thus replacing the gas production profile method. Attached Figure Description

[0038] Figure 1 This is a flowchart of the method of the present invention;

[0039] Figure 2 This is a graph showing the fitting relationship between the unobstructed flow rate and the energy storage coefficient in Embodiment 1 of the present invention;

[0040] Figure 3 This is a graph showing the fitting relationship between the unobstructed flow rate and the energy storage coefficient in Embodiment 2 of the present invention;

[0041] Figure 4 This is a graph showing the fitting relationship between the unobstructed flow rate and the energy storage coefficient in Embodiment 3 of the present invention;

[0042] Figure 5 This is a graph showing the fitting relationship between the unobstructed flow rate and the energy storage coefficient in Embodiment 4 of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer and more understandable, the technical solutions of this invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0044] This invention discloses a method for allocating investment costs in multi-layered tight sandstone gas reservoirs. This method collects data from the blocks to be evaluated, establishes the relationship between gas testing data and energy storage coefficients, and corrects the energy storage coefficients. Based on the corrected energy storage coefficients, the gas production contribution rate of each layer is calculated. The gas production contribution rate can effectively reflect the relative gas production capacity of each layer. Based on the gas production contribution rate, the investment costs of shared facilities (drilling and surface facilities) can be reasonably allocated.

[0045] like Figure 1As shown, the specific steps include the following:

[0046] Step 1: Collect production data for each layer of the wellhead in the block to be evaluated, the total investment cost M of the shared facilities, and the energy storage coefficient of each layer. Data, wellhead production data includes single-layer gas production q n and oil pressure P T Compared to other data, gas test data is easier to obtain, the information is more complete, there is a lot of room for operation, and gas test data can reflect the reserves of the gas layer.

[0047] Step 2: Calculate the unobstructed flow rate Q for each layer using the wellhead production data collected in Step 1. n Compared with the production rate at the test wellhead, the unobstructed flow rate is not affected by human working conditions and can better characterize the production capacity of each layer and compare the gas production capacity between layers. There are many ways to calculate the unobstructed flow rate, and you can choose according to the actual situation.

[0048] Calculating the unobstructed flow rate Q using the "one-point method" n Specifically, calculate according to formula (1):

[0049]

[0050] Among them: Q n Single-layer unobstructed flow rate, q n Single-layer gas production, P T Hydraulic pressure;

[0051] Step 3, by calculating the unobstructed flow rate Q in Step 2 n With the energy storage coefficient collected in step 1 Fitting analysis was performed to establish the relationship between the unobstructed flow rate Qn and the storage coefficient for each layer. The fitting relationship is given by the coefficients of the fitting relationship, which represent the unit energy storage capacity A of each layer. n ;

[0052] Unobstructed flow rate Qn and energy storage coefficient Linear regression analysis was performed to establish a linear regression equation between the unobstructed flow rate and the energy storage coefficient, as shown in formula (2):

[0053]

[0054] Among them, A n The unit energy storage capacity of each layer;

[0055] Step 4: Calculate the unit energy storage capacity A for each layer as determined in Step 3. n Standardization is performed to obtain the standardized unit energy storage capacity of each layer.

[0056] The linear proportional method is used to calculate the unit energy storage coefficient A of each layer. n The standardization process is performed, as shown in formula (3):

[0057]

[0058] in, For A n Dimensionless data, i.e., the standardized unit energy storage capacity of each layer, A n A represents the unit energy storage capacity of each layer. min This represents the minimum energy storage coefficient capacity per unit of each layer; the minimum value for dimensionless data is 1.

[0059] Step 5: Use the standardized unit energy storage capacity obtained in Step 4 to obtain the energy production capacity of each layer. and the energy storage coefficient of each layer Calculate the corrected energy storage coefficient K for each layer n ;

[0060] Corrected energy storage coefficient K n Calculated using formula (4):

[0061]

[0062] Among them, K n The corrected energy storage coefficients for each layer;

[0063] Step 6: Utilize the corrected energy storage coefficients K obtained in Step 5 for each layer. n Calculate the gas production contribution rate G of each layer n ;

[0064] Gas production contribution rate G of each layer n Calculated using formula (5):

[0065]

[0066] Where K1, K2, ..., K n The corrected energy storage coefficients for each layer;

[0067] Step 7, based on the gas production contribution rate G of each layer calculated in Step 6 n The total investment cost M of shared facilities is divided into single-layer investment costs m. n ;

[0068] Single-story investment cost m n Calculated using formula (6):

[0069] m n =G n ×M (6)

[0070] Where, m nFor single-layer investment costs, G n M represents the gas production contribution rate of each floor, and M represents the total investment cost of shared facilities.

[0071] This invention provides a method for allocating investment costs for multi-layered tight sandstone gas reservoirs. This method establishes a relationship between gas testing data and energy storage coefficients, corrects the energy storage coefficients, calculates the gas production contribution rate of each layer based on the corrected energy storage coefficients, and allocates the investment costs of multi-layered shared facilities (drilling and surface facilities) based on the gas production contribution rate.

[0072] To make the objectives, technical solutions, and key points of the present invention clearer, the specific implementation of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0073] Example 1

[0074] (1) Collect gas testing data of all wells in the He 8 and Ma 5 1+2 layers of Shenmu Gas Field, and organize them by single well and single layer;

[0075] (2) Calculate the unobstructed flow rate using the wellhead production data from the test well; in this embodiment, the empirical formula of the "one-point method" is selected to calculate the unobstructed flow rate, and the formula is as follows:

[0076] (3) Through fitting analysis, the relationship between unobstructed flow rate and energy storage coefficient was established. The relationship between the unobstructed flow rate and the energy storage coefficient is obtained through fitting analysis, taking the Shenmu Gas Field Box 8 as an example: Therefore, the unit energy storage coefficient of box 8 is 9.926, such as Figure 2 As shown;

[0077] (4) Based on the unit energy storage coefficient production capacity, the energy storage coefficient is standardized to obtain the corrected energy storage coefficient; This embodiment takes the S327 well in Shenmu Gas Field as an example. The well produces two layers at the same time, He8 and Ma51+2; Step 3 obtained the unit energy storage coefficient production of He8 and Ma51+2 as 9.926 and 37.718 respectively. Based on this, the energy storage coefficient is standardized to obtain the corrected energy storage coefficient. The results are shown in Table 2.

[0078] (5) Calculate the gas production contribution rate of each layer using the corrected energy storage coefficient; calculate the gas production contribution rate of each layer based on the corrected energy storage coefficient obtained in step 4, and the calculation results are shown in Table 1.

[0079] Table 1. Calculation results of energy storage coefficient correction and gas production contribution rate.

[0080]

[0081] (6) Based on the gas production contribution rate of each layer, the investment cost of shared facilities (drilling and surface facilities) is divided into single-layer investment costs.

[0082] Example 2:

[0083] (1) Collect gas testing data of all ancient wells in the Sulige Gas Field and organize them by single well and single layer;

[0084] (2) Using the production data from the test wellhead, the unobstructed flow rate is calculated using the empirical formula of the "one-point method". The formula is as follows:

[0085] (3) By using linear regression analysis, the relationship between unobstructed flow rate and energy storage coefficient is established. The relationship between the flow rate and the energy storage coefficient is obtained by fitting analysis, taking Box 8 of the Sulige Gas Field as an example: Therefore, the unit energy storage coefficient of box 8 is 8.919, such as Figure 3 As shown;

[0086] (4) Based on the unit energy storage coefficient capacity, the energy storage coefficient is standardized to obtain the corrected energy storage coefficient. In this embodiment, the S40 well in the Sulige gas field is used as an example. This well produces three layers: He8, Shan1, and Shan2. In step 3, the unit energy storage coefficient capacity of He8, Shan1, and Shan2 are 8.919, 9.508, and 9.0269, respectively. Based on this, the energy storage coefficient is standardized to obtain the corrected energy storage coefficient. The results are shown in Table 3.

[0087] (5) Calculate the gas production contribution rate of each layer using the corrected energy storage coefficient; calculate the gas production contribution rate of each layer based on the corrected energy storage coefficient obtained in step 4, and the calculation results are shown in Table 2.

[0088] Table 2. Calculation results of energy storage coefficient correction and gas production contribution rate.

[0089]

[0090]

[0091] (6) Based on the gas production contribution rate of each layer, the investment cost of shared facilities (drilling and surface facilities) is divided into single-layer investment costs.

[0092] Example 3:

[0093] (1) Collect gas testing data from all wells in the Jingbian Gas Field and organize them by single well and single layer;

[0094] (2) Using the wellhead production data from the test well, the unobstructed flow rate is calculated using the empirical formula of the "one-point method". The formula is as follows:

[0095] (3) By using linear regression analysis, the relationship between unobstructed flow rate and energy storage coefficient is established. The relationship between the flow rate and the energy storage coefficient is obtained by fitting analysis, taking Box 8 of Jingbian Gas Field as an example: Therefore, the unit energy storage coefficient of box 8 is 9.926, such as Figure 4 As shown;

[0096] (4) Based on the unit energy storage coefficient production capacity, the energy storage coefficient is standardized to obtain the corrected energy storage coefficient; this embodiment takes the S356 well in Jingbian Gas Field as an example, which simultaneously produces He8, Shan1, Shan2 and Ma5. 1+2 Ma Wu 4 1 Step 3 yields six layers: Box 8, Mountain 1, Mountain 2, and Ma Wu. 1+2 Ma Wu 4 1 The unit energy storage coefficients of Ma Wu 5 and Ma Wu 5 are 9.928, 12.145, 11.887, 37.718, 72.479 and 50.86, respectively. Based on these, the energy storage coefficients are standardized to obtain the corrected energy storage coefficients, and the results are shown in Table 4.

[0097] (5) Calculate the gas production contribution rate of each layer using the corrected energy storage coefficient; calculate the gas production contribution rate of each layer based on the corrected energy storage coefficient obtained in step 4, and the calculation results are shown in Table 3.

[0098] Table 3. Calculation results of energy storage coefficient correction and gas production contribution rate.

[0099]

[0100] (6) Based on the gas production contribution rate of each layer, the investment cost of shared facilities (drilling and surface facilities) is divided into single-layer investment costs.

[0101] Example 4

[0102] (1) Collect gas testing data from all ancient wells in the Shenmu Gas Field and organize them by single well and single layer;

[0103] (2) Calculate the unobstructed flow rate using the wellhead production data from the test well; in this embodiment, the empirical formula of the "one-point method" is selected to calculate the unobstructed flow rate, and the formula is as follows:

[0104] (3) Through fitting analysis, the relationship between unobstructed flow rate and energy storage coefficient was established. The relationship between the unobstructed flow rate and the energy storage coefficient is obtained through fitting analysis, taking the Shenmu Gas Field Box 8 as an example: Therefore, the unit energy storage coefficient of box 8 is 5.5667, such as Figure 2 As shown;

[0105] (4) Based on the unit energy storage coefficient production capacity, the energy storage coefficient is standardized to obtain the corrected energy storage coefficient; In this embodiment, the S416 well in Shenmu Gas Field is used as an example. This well produces five formations at the same time: He8, Shan1, Shan2, Taiyuan and Benxi; Step 3 yields the unit energy storage coefficient production of He8, Shan1, Shan2, Taiyuan and Benxi as 5.5667, 5.8015, 13.445, 7.5543 and 29.026, respectively. Based on this, the energy storage coefficient is standardized to obtain the corrected energy storage coefficient. The results are shown in Table 4.

[0106] (5) Calculate the gas production contribution rate of each layer using the corrected energy storage coefficient; calculate the gas production contribution rate of each layer based on the corrected energy storage coefficient obtained in step 4, and the calculation results are shown in Table 4.

[0107] Table 4. Calculation results of energy storage coefficient correction and gas production contribution rate

[0108]

[0109]

[0110] (6) Based on the gas production contribution rate of each layer, the investment cost of shared facilities (drilling and surface facilities) is divided into single-layer investment costs.

[0111] As mentioned earlier, gas production profile test data can effectively reflect reservoir productivity. By comparing the gas production contribution rate obtained based on gas production profile test data and the present invention, the present invention can achieve results that are approximately the same as those obtained from gas production profiles, as shown in Table 5.

[0112] Table 5 Comparison of Gas Production Contribution Rate Calculation Results

[0113]

[0114] It can be seen that the present invention can replace the gas production profile method and effectively solve the problem caused by the lack of gas production profile data.

[0115] This invention provides a method for allocating investment costs in multi-layered tight sandstone gas reservoirs. This method establishes a relationship between gas testing data and the storage coefficient, corrects the storage coefficient, and calculates the gas production contribution rate of each layer based on the corrected storage coefficient. The gas production contribution rate effectively reflects the relative gas production capacity of each layer. Using the gas production contribution rate as a basis, a reasonable allocation of investment costs for shared facilities (drilling and surface facilities) is achieved. This invention can achieve results approximately equivalent to those obtained from gas production profiles, thus replacing the gas production profile method.

Claims

1. A method for allocating investment costs for multi-layered tight sandstone gas reservoirs, characterized in that, By collecting data from the blocks to be evaluated, the relationship between gas test data and energy storage coefficient is established, the energy storage coefficient is corrected, the gas production contribution rate of each layer is calculated based on the corrected energy storage coefficient, and the investment cost of multi-layer shared facilities is divided based on the gas production contribution rate. The specific steps are as follows: Step 1: Collect production data for each layer of the wellhead in the block to be evaluated, the total investment cost M of the shared facilities, and the energy storage coefficient of each layer. n data; The wellhead production data in step 1 includes the production of gas from a single layer. and hydraulic pressure ; Step 2: Calculate the unobstructed flow rate of each layer using the wellhead production data collected in Step 1. ; Step 3, using the unobstructed flow rate calculated in Step 2 With the energy storage coefficient collected in step 1 Fitting analysis was performed to establish the unobstructed flow rate of each layer. With energy storage coefficient The fitting relationship is given by the coefficients of the fitting relationship, which represent the unit energy storage capacity A of each layer. n ; Step 4: Calculate the unit energy storage capacity A for each layer as determined in Step 3. n Standardization is performed to obtain the standardized unit energy storage capacity of each layer. ; Step 5: Use the standardized unit energy storage capacity obtained in Step 4 to obtain the energy production capacity of each layer. and the energy storage coefficient of each layer Calculate the corrected energy storage coefficient for each layer ; Step 6: Utilize the corrected energy storage coefficients obtained in Step 5 for each layer. Calculate the gas production contribution rate of each layer ; Step 7, based on the gas production contribution rate G of each layer calculated in Step 6 n The total investment cost M of shared facilities is divided into single-layer investment costs m. n .

2. The method for allocating investment costs for multi-layered tight sandstone gas reservoirs according to claim 1, characterized in that, In step 2, the "one-point method" is used to calculate the unobstructed flow rate. Specifically, calculate according to formula (1): in: Single-layer unobstructed flow rate Single-layer gas production, Hydraulic pressure.

3. The method for allocating investment costs for multi-layered tight sandstone gas reservoirs according to claim 1, characterized in that, In step 3, the flow rate is unobstructed. With energy storage coefficient Linear regression analysis was performed to establish a linear regression equation between the unobstructed flow rate and the energy storage coefficient, as shown in formula (2): in, The unit energy storage coefficient capacity of each layer.

4. The method for allocating investment costs for multi-layered tight sandstone gas reservoirs according to claim 1, characterized in that, In step 4, the linear scaling method is used to calculate the unit energy storage capacity A of each layer. n The standardization process is performed, as shown in formula (3): in, for The dimensionless data, namely the standardized unit energy storage coefficient capacity of each layer, The unit energy storage capacity of each layer, This represents the minimum energy storage coefficient capacity per unit of each layer; the minimum value for dimensionless data is 1.

5. The method for allocating investment costs for multi-layered tight sandstone gas reservoirs according to claim 1, characterized in that, The corrected energy storage coefficient in step 5 Calculated using formula (4): in, The corrected energy storage coefficients for each layer.

6. The method for allocating investment costs for multi-layered tight sandstone gas reservoirs according to claim 1, characterized in that, The gas production contribution rate G of each layer in step 6 n Calculated using formula (5): in, The corrected energy storage coefficients for each layer.

7. The method for allocating investment costs for multi-layered tight sandstone gas reservoirs according to claim 1, characterized in that, The single-layer investment cost m in step 7 n Calculated using formula (6): in, For single-layer investment costs, G n M represents the gas production contribution rate of each floor, and M represents the total investment cost of shared facilities.

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