【摘要】 四川盆地川西坳陷新场构造带三叠系须家河组二段致密气藏资源潜力巨大，但地质构造复杂，勘探开发面临巨大挑战。尤其是对现今地应力状态和展布规律的认识尚不清晰，严重制约了工程甜点选取、井眼轨迹优化以及储层压裂改造工作的开展。为明确研究区须二段致密气藏现今地应力的分布特征，从岩心试验、矿场测试和测井解释等多个角度切入，明确单井地应力特征；充分考虑构造变形和断裂对地应力的扰动特征，采用Rhinoceros和FLAC^3D软件，对须二段进行了精细的三维应力场建模与预测；基于地应力分布预测结果，选取对压裂和产量影响较大的最小主应力和应力差作为评价指标，对应力场特征进行了分区评价，并对不同应力区井位部署、井轨迹及压裂改造设计给出了初步建议。新场构造带须二段的现今最大水平主应力方向多在N85°—108°E之间，整体随埋深增加逆时针偏转；现今地应力属于走滑应力机制，中部合兴场三向应力明显高于新场和丰谷地区，构造变形和断裂对局部应力场存在扰动。应力分区结果显示，有利于压裂改造的低应力差—低地应力区主要发育在新场和合兴场的三级东西向断裂和四级南北、北东向断裂带附近，以及丰谷地区的构造张性扰动区域。更多还原

【Abstract】 The second member of the Triassic Xujiahe Formation(Xu 2 Member) in the Xinchang structural belt of the Western Sichuan Depression in the Sichuan Basin contains tight gas reservoirs with enormous resource potential.However, the geological structure is complex, presenting significant challenges for exploration and development.In particular, the current understanding of its in-situ stress state and distribution patterns is insufficient, severely restricting the selection of sweet spots for engineering, wellbore trajectory optimization, and reservoir fracturing modification. To clarify the current in-situ stress distribution characteristics in the tight gas reservoirs of the Xu 2Member, the paper analyzed data from core tests, field tests, and well logging interpretation to determine the stress characteristics at individual wells. Considering the disturbances to the stress field caused by tectonic deformation and faults, Rhinoceros and FLAC3Dsoftware were used to precisely model and predict the three-dimensional insitu stress field of the Xu 2 Member. Based on the stress distribution predictions, the minimum principal stress and stress differential, which significantly impacted fracturing and production, were selected as evaluation indicators.The stress field characteristics were zoned and evaluated, and preliminary suggestions were provided for well location deployment, well trajectory, and fracturing modification design in different in-situ stress zones. The results show that the current maximum horizontal principal stress direction in the Xu 2 Member of the Xinchang structural belt mostly ranges from N85° to 108°E, with an overall counterclockwise rotation as burial depth increases. The current in-situ stress regime corresponds to a strike-slip stress mechanism, with the central Hexingchang area showing significantly higher triaxial stress than the Xinchang and Fenggu areas. Moreover, local in-situ stress fields are disturbed by tectonic deformation and faults. The stress zoning results show that the low stress differential and low in-situ stress zones, which are favorable for fracturing modification, mainly develop near the third-order eastwest-trending faults and the fourth-order north-south and northeast-trending faults in the Xinchang and Hexingchang areas, as well as in the extensional disturbance areas in the Fenggu area.更多还原