Experimental Study on Field Actual Shut-In After Fracturing of Shale Gas Reservoir

Hydraulic fracturing has become a crucial method for exploiting shale gas. The test production of shale gas wells can be significantly impacted by different shut-in times and flowback systems, making these data vital for formulating development plans formulation and evaluating productivity. This study proposes a workflow of field shut-in experiments combined with chloride ion concentration observations, using the engineering method. Moreover, the study optimizes some reservoir testing details in the study area (the best testing time was 22 days, and the optimal shut-in time is 30 days). The conclusions of this study are as follows: (1) each production area can be optimized on geological conditions and engineering data statistics, and the combined analysis of microseismic monitoring and well shut-in experiments can yield the optimal value for multiple factors. (2) The observation of chloride ion concentration, as part of the geochemical method, can easily determine the storage characteristics, distribution status, and return characteristics of the drainage fluid in the reservoir. Furthermore, the well shut-in experiment can accurately assess the impact of the drainage and mining working system on production capacity. (3) The present study shows that when the chloride ion concentration of the drainage fluid tends to stabilize over a long period, the reservoir test can be concluded, and normal production can commence.