Experimental testing method for soaking time of shale reservoir horizontal well

Abstract

The invention discloses an experimental testing method for the soaking time of a shale reservoir horizontal well. The experimental testing method comprises the steps that a rock sample is prepared according to rock of a shale reservoir section and dried to constant weight; the clay mineral content of the rock sample is obtained; a hydrophilicity index of the rock sample is obtained; a clay mineralcontent and hydrophilicity index curve is fitted, and a clay mineral content critical value is determined; the soaking time is qualitatively judged according to the critical value of the clay mineralcontent; the soaking time is quantitatively tested, nuclear magnetic resonance scanning is conducted on a rock core, a correlation curve of T2 spectrum curve peak area and imbibition test time is drawn, and an inflection point corresponding to the correlation curve is taken as the soaking time. According to the experimental testing method, a method for rapidly determining the soaking time is provided, mine field engineers can qualitatively and quantitatively determine the soaking time through the method, and the development efficiency is greatly improved.

Description

technical field [0001] The invention relates to the field of petroleum and natural gas engineering, in particular to an experimental test method for the soaking time of horizontal wells in shale reservoirs. Background technique [0002] The shale of the Longmaxi Formation in the Sichuan Basin is the main shale gas development area in China. The volume pressure technology of horizontal wells has realized the large-scale commercial development of shale gas. The phenomenon of high flowback rate and high productivity (Liu Naizhen, Liu Ming, Zhang Shicheng. Flowback law of shale gas wells after pressure[J]. Natural Gas Industry, 2015,35(3):50-54). Among them, the hydration of shale clay minerals and fracturing fluid induces micro-cracks, improves the flow capacity of shale reservoirs, and the continuous transformation of shale reservoirs is an important reason for the above special flowback characteristics. A large number of field statistics show that However, when the clay cont...

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Problems solved by technology

Among them, the hydration of shale clay minerals and fracturing fluid induces micro-cracks, improves the flow capacity of shale reservoirs, and the continuous transformation of shale reservoirs is an important reason for the above special flowback characteristics. A large number of field statistics show that However, when the clay content is high, the clay mineral lattice expands, and clay particles migrate, which brings certain damage to the reservoir (Sui Weibo, Tian Yingying, Yao Chenhao. Shale Fixed-point observation experiment of hydration microscopic pore structure changes[J]. Petroleum Exploration and Development, 2018, 45(05): 150-157.), making it difficult to determine whether shale gas wells in the mine need to be soaked and when. The soaking time of shale gas wells is mostly determined by the experience of reservoir engineers or long-term production data statistics, which greatly affects the efficient development of shale gas

[0003] At present, the methods for determining the soaking time of shale gas wells are mainly divided into the statistical method of mineral production data (Du Yang, Lei Wei, Li Li, et al. Shale gas well blowout mode after fracturing[J]. Lithologic Reservoirs, 2019, 31(3):146-151) and theoretical model calculation method (Zhang Tao, Li Xiangfang, Yang Lifeng, et al. Effect of well shut-in timing on flowback rate and productivity of shale gas wells[J]. Natural Gas Industry, 2017, 37(8 ):48-60.), in which the field data statistics method requires long-term production testing. Due to the strong heterogeneity of shale reservoirs, the flowback of different shale gas wells varies greatly, and special well treatment is required, so it is impossible to Other wells provide reliable references

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