Research And Application Of Ground Stress Characteristics Of The Fifth Member Of Xujiahe Formation In Xinchang Gas Field

This research focuses on the experiment about rock mechanics parameters of the fifth member of Xujiahe formation system. The author gets the hung of the character of the sandstone of the Xujiahe formation, elastic and intensity of parameters characteristics of mudstone.And then the change of the sand shale is distinctive. The intensity of the sandstone is more than the mudstone’s. The main factor of the sandstone is elastic deformation. The main factor of the mudstone is plastic deformation. As confining pressure increases, the intensity of the yield stress increases and the increasing rate of the sandstone is faster than other’s. The intensity of the sandstone’s yield stress is more than the intensity of the mudstone’s. Whereby, the yield strain of the mudstone is more than other’s. When the confining pressure increases, the compressive strength and Young’s modulus of the sandstone is increasing. The Poisson’s ratio discrete. When the confining pressure increases, three parts of mudstone increase. Under the condition of confining pressure,The compressive strength, tensile strength, cohesion, angle of internal friction, Young’s modulus of sandstone are less than mudstone’s,but, the Poisson’s ratio of sandstone is less than mudstone’s. The author builds the dynamic and static parameter transformation relationship and uses logging data to build the rock mechanics parameter prediction model such as compressive strength, tensile strength, cohesion, angle of internal friction, Young’s modulus of the formation of rock and so on and build rock mechanics parameters section. The author studies the distribution characteristics of rock mechanics parameters and analyze it. In terms of the Poisson’s ratio of sandstone is much more than mudstone’s. The compressive strength of sandstone is much more than mudstone’s,The dynamic Poisson’s ratio’s degree of the sandstone is zero point zero two more than the mudstone’s. The compressive strength of sandstone is much more than the mudstone’sThe author builds the normal compaction curve and makes optimization of pore pressure prediction methods. In the final, the author of the article chooses Eaton method to predict the region’s pore pressure. Based on the basis of it, the author of this adopts the Acoustic emission experiment,differential strain test and fracturing data to obtain the value of in-situ stress of Xujiahe 5th member formation of Xing Chang Area and uses ADS method to determine the logging interpretation model of ground stress. Comparing the measured values, the error is little. So, the author builds in-situ stress profile. According to Paleomagnetic test, The imaging logging and Microseismic monitoring, the author determines the direction of In-situ stress is Nearly eastwestern.Study on the factors of Xinchang area section stress distribution, respectively from the rock mechanics properties and lithology, depth and structure and other aspects are discussed respectively. In general the Xinchang gas field mainly affect the level of rock mechanical parameters of paragraph five of the maximum and minimum principal stress and vertical stress has little effecton. It is better than the effect on sandstone mudstone.Increasing depthe of sandstone and mudstone, the vertical stress and increase the level of the minimum principal stress is similar, and the maximum principal stress of the rate of increase is greater than the sandstone, mudstone.Current structural parts such as structural highs and wings tructures such as faults and fractures of different tectonicterrain and steep structures, such as steep down end, saddlet end to produce stress anomaly zone, resulting incrustal stress distribution characteristics of the different. Especially in the end, fault point and fault intersectionor, often occur in the stress concentration and stress disturbance.