川西新场构造地应力分布规律研究及其应用

RESEARCH ON THE DISTRIBUTION LAWS OF TECTONIC IN-SITU STRESS IN XINCHANG STRUCTURE (WEST SICHUAN BASIN)AND THEIR APPLICATIONS

在充分利用现场加砂压裂、测试压裂数据的基础上,精确求取了新场构造不同层位的最小地应力值,并将该最小地应力与压裂测试同期地层压力建立联系,研究发现该区最小地应力与对应地层压力之差值与垂直深度呈线性关系,且相关性极高。该公式的提出解决了新场构造须家河组压裂资料少、裂缝闭合压力求取难的问题,为钻井、固井、压裂施工提供了科学指导;该区须家河组应力绝大部分处于走滑应力状态,最小地应力为最小水平应力;针对须家河组钻井诱导张性裂缝发育的现象,还推导了水平最大地应力的计算公式,并应用到几口重点深井的地应力场求解中,为须家河组天然裂缝渗透性分析提供了准确的地应力模型。

On the basis of making full use of data on field sand fracturing and test fracturing,the minimum in-situ stress values at different reservoir intervals of the Xinchang structure are obtained accurately and the relationship between minimum in-situ stress and the contemporaneous formation pressure of fracturing testing are established.It is found that the stress difference between the minimum in-situ stress and reservoir pressure is linearly correlated with vertical depth and their correlation is extremely high.This formula solved the difficulties existing in the Xujiahe formation of the Xinchang Structure,such as lack of fracturing data and hard to obtain fracture closure pressure,which has provided scientific guidance for drilling,cementing and fracturing construction;the Xujiahe formation stress in this area is mostly in a strike-slip stress state and the minimum in-situ stress is the minimum horizontal stress;based on the development phenomenon of drilling induced tensile fractures existing in the Xujiahe formation,the formula for horizontal maximum in-situ stress is deduced and applied in in-situ stress of some key deep wells to obtain solutions,which provides accurate in-situ stress model for natural fracture permeability analyses of the Xujiahe formation.