The downhole pressure data acquisition system and its application in hydraulic fracturing in- situ stress testing
WANG Jianxin1，ZHAGN Ce1，GUO Qiliang1，LI Bing1，LIU Xiaoli2
(1. Key Laboratory of Crustal Dynamics，The Institute of Crustal Dynamics，CEA，Beijing 100085，China；2. State Key Laboratory of Hydroscience and Engineering，Tsinghua University，Beijing 100086，China)
Abstract：The downhole pressure data acquisition system has first been developed by the Institute of Crustal Dynamics. According to accurately recording the water pressure in a hydraulic fracturing test section，the system can not only eliminates the effects of hydraulic fracturing test system compliance and pore water pressure unevenness in the hole wall，but also greatly improves accuracy of the hydraulic fracturing system. The system has been successfully applied in practice，and its running stability and environmental suitability are satisfied to the requirements of further applications. Recently，two in-situ stress tests were successfully carried out by our work team，then the paper conducted a comparison of the two test results based on the data obtained by downhole and ground data acquisition system respectively. The results show that the test errors become larger with the test depth increasing. Moreover，both of two pressure gradients recorded by ground and downhole data acquisition systems are consistent during the pressure increasing stage，nevertheless，the pressure gradient obtained by ground data acquisition system is significantly greater than the one recorded by downhole system during pressure decreasing stage. The stress characteristics and in-situ stress values，especially reopen pressure，are smaller by ground system than those values obtained by downhole system.
王建新1，张 策1，郭啓良1，李 兵1，刘晓丽2. 水压致裂原地应力测试井下水压力数据采集系统及其应用研究[J]. 岩石力学与工程学报, 2016, 35(S2): 3971-3976.
WANG Jianxin1，ZHAGN Ce1，GUO Qiliang1，LI Bing1，LIU Xiaoli2. The downhole pressure data acquisition system and its application in hydraulic fracturing in- situ stress testing. , 2016, 35(S2): 3971-3976.
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2016, Vol. 35 
