川东北马路背地区裂缝对须二段储层的影响

The Fracture Effects on Reservoir in the Second Member of the Xujiahe Formation in Malubei Structure, Northeast Sichuan Basin

摘要: 通过区域构造分析，川东北马路背地区为大巴山与米仓山前缘构造转换带。在构造精细解释的基础上，对断层和裂缝的特征进行刻画。按照裂缝的成因，预测出不同类型的裂缝在工区展布特征。与区域构造应力相关的构造裂缝是研究区高角度缝的主要成因，主要发育在断裂带附近。马路背工区处于转换带位置，工区内由Ⅰ类断层分割形成的三个断块，通过调节断块间断距的变化来调节构造的变形，形成了与构造断裂斜交的裂缝，转换带裂缝主要发育在靠近Ⅰ类大断层的共轭方向以及断层相交部位。通过高产井证实，转换带裂缝与构造裂缝形成的网状缝，是马路背地区须二特低孔低渗储层稳产的关键因素。研究认为马路背构造转换带形成的裂缝系统，与优质储层匹配形成的储渗体，是下步开发的有利目标。

Abstract: Malubei area, located in north Sichuan Basin, is considered as the structural transform zone of the front of Micang-Daba Mountains based on regional structure analysis. The characters of faults and fractures can be clearly described on the basis of fine structural interpretation. According to the genesis, the distribution of different types of fractures can be predicted in the studied area. The structural fractures associated with regional structural stress are the main causes of high-angle fractures in the study area, mainly developed in the vicinity of the fault zone. Influenced by the structural transform zone, the class of I fault blocks is formed by the three fault zones, which adjust the deformation of structure by accommodating the fault throw, and formed the fractures obliquely with the structural fractures. The fracture of the transition zone is mainly developed in the direction of conjugate direction of nearly the large fault and the intersection position of the fault. Confirmed by high yield wells, the fracture of the transition zone coupled with structural fracture formed net-fractures, which considered as the main controlling factor to keep stable production of extra-low permeability, porous reservoir in member 2 of Xujiahe formation. The research shows that the fracture system formed by Malubei structural transform zone coupled with the favorable reservoir develop into effective storage-permeation bodies, which will be the favorable oil-gas development targets in the future.