Study And Application Of Geo-stress Field With Acoustic Emission Experiment In Yanchang Gas Field

With the increasing difficulty of oilfield development,Geo-stress research is becoming much more important.Such as,owing to the lack of further understanding of Geo-stress field on the process of drilling engineering results in borehole sloughing and causes huge economic losses.In this paper,based on finite element-difference theory,using acoustic emission experiments to obtain x block in-situ stresses of Yanchang Gas Field,in virtue of ABAQUS finite element analysis software simulates in-situ stress of the block and the regular distribution patterns of geo-stress near the borehole,gets the distribution of geo-stress near the borehole in different drilling fluid density by the simulation,judges by the MC shear failure criterion and the distribution of circumferential stress near borehole to determine the stability of sidewall,furthermore,decides the safety of drilling fluid.In the course of the study,comparing the finite element simulation results with experimental results finds that the vertical stress matches to the inner experimental result but the horizontal stress have much further difference with the inner experimental results.The influence of tectonic stress and other factors makes the difference.Then,using numerical fitting method to deal with the data and simulates In-situ stress again,gets a good agreement between the simulations and inner experimental results and the error range can be controlled within 6%.