A shale gas multi-stage fractured horizontal well post-fracturing crack parameter evaluation method and system

Abstract

The invention discloses a shale gas multi-stage fracturing horizontal well post-fracturing crack parameter evaluation method and system. The method comprises the following steps: 1) aiming at a targetshale gas field, collecting static geological parameters, dynamic data and pipe column parameters of a plurality of shale gas multi-stage fractured horizontal wells; 2) obtaining values of fracturingtransformation stratum coefficients of the plurality of wells; 3) obtaining a dynamic total reserve value of each well; 4) establishing an empirical relationship between the fracturing transformationstratum coefficient and the total geological reserve of the volume fracturing transformation area according to data obtained in the steps 2 and 3; 5) obtaining the total geological reserve of the volume fracturing reconstruction area; 6) calculating the half length of the effective support hydraulic fracture; and 7) performing gas well production history fitting and / or shut-in pressure recovery well test chart fitting based on the crack half-length constraint to obtain a fracturing transformation parameter evaluation result. According to the method, the problem of high historical fitting multiplicity can be solved, a more reliable fracturing transformation parameter interpretation result is obtained, and a basis is provided for predicting the gas well productivity and making a reasonabledevelopment technical policy in the next step.

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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