A comprehensive evaluation method for hydration capacity of heterogeneous shale reservoirs

Abstract

The invention discloses a comprehensive evaluation method for the hydration capacity of heterogeneous shale reservoirs, which comprises the steps of: preparing rock samples according to rocks in shale reservoir sections, and drying the rock samples to constant weight; measuring the rock samples The porosity and permeability of the rock sample are obtained according to the porosity and permeability; the mineral composition of the rock sample is measured, and the brittleness index of the rock sample is obtained according to the mineral composition; the rock sample imbibition test is carried out , to obtain the hydrophilic index of the rock sample; through the physical property index, brittleness index, and hydrophilic index of the rock sample, the comprehensive index of rock sample hydration is determined, and the comprehensive index of rock sample hydration is used to evaluate the hydration ability of shale rock samples. Overview. This method can quantitatively characterize the hydration ability of shale, and its test and application method is simple to operate, the calculation result is more accurate, and does not require a large number of field experiments, which greatly reduces the economic cost and saves the soaking time of shale gas wells. Optimization provides an important scientific basis.

Description

technical field [0001] The invention relates to the field of petroleum and natural gas engineering, in particular to a comprehensive evaluation method for the hydration capacity of heterogeneous shale reservoirs. Background technique [0002] Horizontal well segmented multi-cluster volume fracturing is a key technology for efficient development of shale gas. Different from conventional sandstone, due to differences in geological characteristics and fracturing techniques, shale gas wells show special flowback characteristics after volume fracturing : Negative correlation between gas production and flowback rate, decrease in water production after simmering, increase in gas production, large difference in flowback rate, etc. (Dong Dazhong, Wang Yuman, Li Xinjing, et al. Thoughts on new breakthroughs and development prospects of China's shale gas exploration and development[J ]. Natural Gas Industry, 2016, 36(1): 19-32). [0003] At present, due to the special flowback charact...

AI Technical Summary

Problems solved by technology

[0008] The above methods are single-factor qualitative analysis of rock mechanical properties and microstructure changes during shale hydration, and lack quantitative characterization of shale hydration capacity

At the same time, the water-phase imbibition and hydration of shale reservoirs are a dynamic equilibrium process. Shale hydration induces micro-cracks, which further promotes the shale's hydrophilic ability. Conversely, the increase of shale's hydrophilic ability further promotes shale hydration. Therefore, how to quantitatively test the hydrophilic ability of shale plays an important role in evaluating the hydration of shale reservoirs, and previous studies did not consider the influence of reservoir confining pressure and temperature on shale hydration, while shale is usually In high-temperature and high-pressure reservoirs, it is difficult to answer the question whether shale water phase imbibition can induce micro-fractures under the confining pressure and temperature conditions of the reservoir. Therefore, it is necessary to comprehensively consider different factors to quantitatively characterize the hydration capacity of shale, and then Provide scientific basis for optimization of shale gas well flowback system

Images