A method for measuring the productivity of shale gas wells

Abstract

The invention relates to a method for calculating the productivity of a shale gas well. According to the characteristics of fracturing and non-fracturing stimulation areas in the single well control area of ​​shale gas reservoirs, the present invention comprehensively considers the influence of adsorbed gas desorption diffusion and fracturing and non-fracturing stimulation areas on the productivity of shale gas wells, A material balance equation for dual-zone composite shale gas reservoirs considering adsorbed gas is established, combined with the gas well productivity equation and the channeling equation between the two zones, a fast and accurate calculation method for shale gas well productivity is established. This method does not require complex geological models of shale gas reservoirs, nor does it require many geological and fracturing dynamic parameters. The calculation results are suitable for various applications such as rational production allocation of shale gas wells, development technology policy and development plan optimization.

Description

technical field [0001] The invention relates to geophysical prospecting technology, in particular to a method for measuring the productivity of shale gas wells. Background technique [0002] Shale gas refers to the accumulation of oil and gas in which the main body is located in dark black mud shale rich in organic matter, and the main storage mode is adsorption or free state. Shale is not only a reservoir, but also a source rock and a sealing layer. [0003] Shale gas reservoirs are dual-medium gas reservoirs composed of ultra-low permeability matrix pores and naturally closed natural fractures. The matrix is ​​the main storage space for free gas and adsorbed gas. The natural production capacity of shale gas wells is very low, and the industrial production capacity can only be obtained after the formation of "man-made gas reservoirs" through multi-stage fracturing volume stimulation of horizontal wells. At this time, the fracture network is the main channel for seepage, and...

AI Technical Summary

Problems solved by technology

Due to the different production methods of shale gas wells at home and abroad, it is impossible to use the empirical relational formula formed based on a large number of production data statistics abroad to measure the productivity of shale gas wells in China.

The production decline analysis requires that the bottom hole pressure does not change much, and the gas well can only be used when it has entered the decline stage for more than half a year. However, domestic gas wells are mainly produced in the way of pressure control and stable production in the initial stage of production, so the production decline analysis method cannot be used for gas wells in the early stage of production. Calculation of production capacity

The single well numerical simulation method requires a lot of strict geological and fracturing parameters, and these parameter values ​​are often difficult to set accurately, resulting in large errors in the shale gas well productivity results calculated by the single well numerical simulation method at the early stage

Systematic well testing can only reflect the maximum gas production potential of the gas well at the initial stage of production, and cannot directly and accurately obtain the stable production period, production decline and final cumulative gas production of the gas well

[0006] To sum up, although the existing shale gas reservoir productivity calculation methods have their own strengths, they are difficult to use due to the limitation of production methods and other objective factors, and it is difficult to obtain effective and accurate shale gas well productivity analysis results. in the early stages of shale gas reservoir development

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