Fracturing construction transformation effect evaluation method based on numerical modeling

Abstract

The invention belongs to the technical field of oil and gas reservoir transformation, and discloses a fracturing construction transformation effect evaluation method based on numerical modeling. Comprising the steps of establishing a fracture-reservoir conventional fracturing productivity numerical model and a fracture-SRV-reservoir volume fracturing productivity numerical model, simulating and predicting the yield, fitting data and comparing, analyzing and judging. In the evaluation process, production data history fitting is used as a model accuracy inspection standard, and the accuracy of an explanation result can be ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas reservoir transformation, and in particular relates to a method for evaluating the effect of fracturing construction transformation based on numerical modeling. Background Art

[0002] In recent years, due to the gradual deterioration of oil and gas resource endowment, low permeability, ultra-low permeability and unconventional oil and gas resources have gradually become the main body of domestic oil and gas exploration and development. According to the results of domestic and foreign development practices, oil and gas reservoir production enhancement technology represented by large-scale volume fracturing technology has the characteristics of being applicable to a wide range of reservoir types and having obvious production enhancement effects. It is an important means to effectively develop such low-porosity and low-permeability oil and gas reservoirs.

[0003] The ultimate goal of volume fracturing technology is to fully break up the reservoir, form a complex fracture network, obtain the shortest oil and gas seepage distance, the maximum fracture-controlled reserves and the highest recovery degree. However, whether the above goals can be achieved depends on whether a complex fracture network area with a certain conductivity is formed near the wellbore after the construction is completed. In order to clarify the key issues in this fracturing technology, the evaluation of reservoir fracturing construction and transformation effects has received increasing attention.

[0004] At present, there are two main methods for evaluating the effect of fracturing construction and transformation. One is to use microseismic, optical fiber sensing, inclinometer and other equipment for direct monitoring or to use the monitoring results for numerical modeling and model correction, and the other is indirect methods such as well test analysis, construction data inversion, theoretical formula calculation, etc. However, the above methods have problems such as complex operation, long evaluation cycle, high cost, and multiple solutions of interpretation results. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a method for evaluating the effect of fracturing construction based on numerical modeling. By judging whether a complex fracture network zone is formed after volume fracturing transformation by equivalently characterizing the high permeability SRV area, a rapid and low-cost evaluation of the overall transformation effect of volume fracturing can be achieved.

[0006] The above object of the present invention is achieved through the following technical solution: A method for evaluating the effect of fracturing construction based on numerical modeling, comprising the following steps:

[0007] 1. According to the relevant geological parameters, engineering parameters and production data of the area where the fracturing wells are located, the numerical model of fracture-reservoir conventional fracturing capacity and the numerical model of fracture-SRV-reservoir volume fracturing capacity are established respectively;

[0008] 2. Use conventional fracturing capacity numerical model and volume fracturing capacity numerical model respectively, and use the same production system to simulate and predict production;

[0009] 3. Fit the model prediction production with the actual production data by adjusting the parameters of the conventional fracturing production capacity numerical model and the volume fracturing production capacity numerical model;

[0010] 4. Compare and analyze the model parameters after production history fitting with the known actual reservoir parameters to determine whether the constructed well has achieved the transformation effect of volume fracturing.

[0011] Furthermore, the step 1 includes: establishing a fracture-reservoir conventional fracturing capacity numerical model and a fracture-SRV-reservoir volume fracturing capacity numerical model respectively, the difference between the two being that the volume fracturing SRV area is characterized by modifying the local permeability of the reservoir where the fracture is located, and the remaining fracture model and reservoir model parameters in the capacity numerical model remain consistent.

[0012] Furthermore, the step 2 includes: after the model is established, the actual production system of the fracturing well after opening is used as the production system of the conventional fracturing capacity numerical model and the volume fracturing capacity numerical model to simulate the production, and the other production parameters in the capacity numerical model remain consistent.

[0013] Furthermore, step 3 includes: performing historical fitting between the predicted production and the actual production by adjusting the reservoir permeability Kr in the conventional fracturing capacity numerical model, and performing historical fitting between the predicted production and the actual production by adjusting the SRV regional permeability Ks in the volumetric fracturing capacity numerical model.

[0014] Furthermore, step 4 includes: comparing the final reservoir permeability Kr of the conventional fracturing capacity numerical model after completing the historical fitting of the production data with the known reservoir permeability K, and comparing and analyzing the final SRV regional permeability Ks of the volume fracturing capacity numerical model after completing the historical fitting of the production data with the known reservoir permeability K, to determine whether the constructed well has achieved the transformation effect of volume fracturing.

[0015] Compared with the prior art, the beneficial effects of the present invention are: compared with the method of evaluating the volume fracturing effect by directly monitoring the crack technology through instruments such as microseismic, optical fiber sensing, inclinometers, etc., the present invention has the characteristics of low evaluation cost, strong operability, and short evaluation cycle. Indirect methods such as well test analysis, construction data inversion, and theoretical formula calculation can only obtain the post-fracturing crack size, conductivity, and some geological parameters of the reservoir, and cannot judge the overall fracturing transformation effect. The present invention can achieve the purpose of overall transformation effect evaluation by judging whether a complex fracture network belt is formed after fracturing transformation with high permeability SRV area equivalent characterization. At the same time, the present invention uses production data history fitting as the model accuracy test standard in the evaluation process, which can ensure the accuracy of the interpretation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0017] Figure 1 It is a design flow chart of a method for evaluating the effect of fracturing construction and transformation based on numerical modeling of the present invention;

[0018] Figure 2 It is a numerical model diagram of conventional fracture-reservoir production capacity in the following embodiments of the present invention;

[0019] Figure 3 It is a numerical model diagram of fracture-SRV-reservoir volume fracturing capacity in the following embodiments of the present invention;

[0020] Figure 4 It is a graph of the actual production system of the construction well in the following embodiment of the present invention;

[0021] Figure 5 It is a historical fitting result diagram of production data of the conventional fracture-reservoir productivity numerical model in the following embodiments of the present invention;

[0022] Figure 6 It is a historical fitting result diagram of production data of the fracture-SRV-reservoir volume fracturing productivity numerical model in the following embodiments of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below by specific examples, but the protection scope of the present invention is not limited. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0024] Example 1

[0025] The present invention provides a method for evaluating the effect of hydraulic fracturing construction based on numerical modeling, and its specific implementation process is as follows: Figure 1 As shown, the following steps are included:

[0026] (1) Based on the relevant geological parameters, engineering parameters and production data of the area where the fracturing construction wells are located, a numerical model of conventional fracture-reservoir fracturing capacity and a numerical model of fracture-SRV-reservoir volume fracturing capacity are established respectively; (2) The conventional fracturing capacity numerical model and the volume fracturing capacity numerical model are used respectively to simulate and predict the production using the same production system; (3) The model predicted production is fitted with the actual production data by adjusting the parameters of the conventional fracturing capacity numerical model and the volume fracturing capacity numerical model; (4) The model parameters after the production history fitting are compared and analyzed with the known actual reservoir parameters to determine whether the construction well has achieved the transformation effect of volume fracturing.

[0027] The step (1) specifically comprises:

[0028] According to the relevant geological parameters, engineering parameters and production system of the area where the fracturing wells are located, the numerical model of conventional fracturing capacity of fracture-reservoir and the numerical model of fracture-SRV-reservoir volume fracturing capacity are established respectively, such as Figure 2 , Figure 3 As shown in the figure, a vertical well single-layer fracturing in an oil field is taken as an example. The reservoir section of the well is located at 4635.6-4650.3m, the temperature is 120℃, the effective thickness is 13.6m, the reservoir permeability is 0.36mD, the reservoir porosity is 0.106, and the crude oil density in the layer is 0.89g / cm 3 , phase permeability data are complete.

[0029] The software used in the geological-engineering integrated capacity numerical model established in this step is Wellwhiz, but other software that meets the functional requirements can also be used in actual applications.

[0030] The step (2) specifically comprises:

[0031] After the model is established, the actual production system of the volume fracturing well after well opening is used as the production system of the conventional fracturing capacity numerical model and the volume fracturing capacity numerical model for production simulation. The other production parameters in the capacity numerical model remain the same. The specific production system is as follows: Figure 4 shown.

[0032] The step (3) specifically comprises:

[0033] The predicted production and actual production were historically matched by adjusting the reservoir permeability Kr in the conventional fracturing capacity numerical model, and the predicted production and actual production were historically matched by adjusting the SRV regional permeability Ks in the volume fracturing capacity numerical model. The fitting results are shown in the figure below. Figure 5 , Figure 6 shown.

[0034] The step (4) specifically comprises:

[0035] The final reservoir permeability of the conventional fracturing capacity numerical model after completing the historical fitting of production data is 3.6mD, which is ten times the known reservoir permeability of 0.36mD. When the volumetric fracturing capacity numerical model completes the historical fitting of production data, the SRV area permeability is 50 times the reservoir permeability. It can be seen that the reservoir permeability obtained by fitting the conventional fracturing capacity numerical model is too high, and the parameters obtained by fitting the volumetric fracturing capacity numerical model are more reasonable. It is believed that the overall fracturing transformation effect is better, and a complex fracture network zone is generated in the near-well area, achieving the expected construction purpose.

[0036] The above-described embodiments are only preferred embodiments of the present invention, but not all feasible embodiments of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating the effect of hydraulic fracturing construction based on numerical modeling, characterized in that: The following steps are involved: S1. According to the relevant geological parameters, engineering parameters and production data of the area where the fracturing well is located, a numerical model of conventional fracturing capacity of fracture-reservoir and a numerical model of fracture-SRV-reservoir volume fracturing capacity are established respectively; S2. Use conventional fracturing capacity numerical model and volume fracturing capacity numerical model respectively, and use the same production system to simulate and predict production; S3. Fitting the model predicted production with the actual production data by adjusting the parameters of the conventional fracturing production capacity numerical model and the volume fracturing production capacity numerical model; S4. Compare and analyze the model parameters after the production history fitting is completed with the known actual reservoir parameters to determine whether the constructed well has achieved the transformation effect of volume fracturing.

2. The method for evaluating the effect of hydraulic fracturing construction based on numerical modeling according to claim 1, characterized in that: The step S1 comprises: establishing respectively a fracture-reservoir conventional fracturing capacity numerical model and a fracture-SRV-reservoir volume fracturing capacity numerical model, the difference between the two being that the volume fracturing SRV area is characterized by modifying the local permeability of the reservoir at the location of the fracture, and the other fracture model and reservoir model parameters in the capacity numerical model remain consistent.

3. The method for evaluating the effect of hydraulic fracturing construction based on numerical modeling according to claim 1, characterized in that: The step S2 includes: after the model is established, the actual production system of the fracturing well after opening is used as the production system of the conventional fracturing capacity numerical model and the volume fracturing capacity numerical model to simulate the production, and the other production parameters in the capacity numerical model remain consistent.

4. The method for evaluating the effect of hydraulic fracturing construction based on numerical modeling according to claim 1, characterized in that: The step S3 includes: performing historical matching between the predicted production and the actual production by adjusting the reservoir permeability Kr in the conventional fracturing capacity numerical model, and performing historical matching between the predicted production and the actual production by adjusting the SRV regional permeability Ks in the volumetric fracturing capacity numerical model.

5. The method for evaluating the effect of hydraulic fracturing construction based on numerical modeling according to claim 1, characterized in that: The step S4 includes: comparing the final reservoir permeability Kr of the conventional fracturing capacity numerical model after completing the historical fitting of the production data with the known reservoir permeability K, and comparing and analyzing the final SRV regional permeability Ks of the volume fracturing capacity numerical model after completing the historical fitting of the production data with the known reservoir permeability K, to determine whether the constructed well has achieved the transformation effect of volume fracturing.

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