A method and system for evaluating fracture parameters after fracturing of multi-stage fracturing horizontal wells in shale gas

Abstract

A post-fracture fracture parameter evaluation method and system for multi-stage fracturing horizontal wells in shale gas are disclosed. The method includes: 1) collecting static geological parameters, dynamic data and string parameters of multiple shale gas multi-stage fractured horizontal wells for a target shale gas field; 2) obtaining the values ​​of the fracturing stimulation formation coefficients of multiple wells; 3) Obtain the dynamic total reserves value of each well; 4) According to the empirical relationship between the formation coefficient of the fracturing stimulation and the total geological reserves of the volume fracturing stimulation area; 5) Obtain the total geological reserves of the volume fracturing stimulation area; 6) Calculation Effectively support the hydraulic fracture half-length; 7) Based on the fracture half-length constraint, perform gas well production history matching and / or shut-in pressure recovery test pattern fitting to obtain the evaluation results of fracturing stimulation parameters. The invention can solve the problem of strong multiple solutions in history matching, obtain more reliable interpretation results of fracturing reconstruction parameters, and provide a basis for predicting gas well productivity in the next step and formulating reasonable development technical policies.

Description

technical field [0001] The invention relates to the field of shale gas exploration and development, and more specifically, to a post-fracture evaluation method and system for a shale gas multi-stage fracturing horizontal well. Background technique [0002] Shale gas is one of the important new areas of natural gas exploration and development. my country is actively promoting the commercialization of the shale gas industry. At present, four major shale gas production areas, namely Fuling, Changning, Weiyuan and Yanchang, have been initially formed and have accumulated a large amount of natural gas. Gas well production performance data. Accurately understanding the effect of fracturing stimulation during the development of shale gas wells is very important for the prediction of gas well productivity and the optimization of development technology policies. [0003] The pore diameter of shale matrix is ​​generally nanoscale, and the porosity and permeability are extremely low. I...

AI Technical Summary

Problems solved by technology

Due to large fluctuations in production data, low pressure and production sampling frequency, and poor accuracy, it is much more difficult to identify a specific flow stage from production data than shut-in pressure recovery testing, and the uncertainty increases

[0010] It can be seen from the above that the existing shale gas multi-stage fracturing horizontal well fracture parameter evaluation methods will encounter problems such as strong interpretation results and difficult determination of stimulation parameters in the actual application process. The productivity of fractured horizontal wells is not only determined by the basic geological parameters, but also controlled by the fracturing effect in the SRV area, and the fracturing effect is not only affected by the fracturing technology and operating parameters, but also depends on the geological conditions (such as shale reservoir Burial depth, content of brittle minerals, degree of development of structural fractures and micro-fractures, etc.) and rock mechanics parameters (Boson's ratio, Young's modulus, horizontal stress difference, etc.), resulting in large differences in fracturing effects between wells

Shale gas multi-stage fractured horizontal wells can hardly show radial flow characteristics within the actual production time range, and the unstable flow period (such as linear flow characteristics) is much longer than conventional gas wells, so it is difficult to recover well test analysis through shut-in pressure Or the analysis of production data accurately determines the basic geological parameters and SRV fracturing parameters, resulting in the interpretation results being greatly affected by human factors

For example, in the case of a short production history, it is possible to use the combination of "lower permeability + larger SRV reformed fracture length and volume" or "higher permeability + smaller SRV reformed fracture length and volume". It satisfies the well shut-in pressure recovery test analysis chart fitting and production data history matching, but the basic geological parameters and fracturing stimulation parameters corresponding to the two cases are very different, thus giving the fracturing effect evaluation and gas well productivity evaluation (EUR) Bringing a completely different understanding, affecting the development decision-making and production management of shale gas reservoirs

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