曹妃甸21￣3构造馆陶组断层封闭性研究

Study on fault sealing properties of Guantao Formation in Caofeidian 21-3 structure, Chengbei Sag, offshore Bohai Bay Basin

 汪晓萌 李慧勇 茆利 赵清平 石文龙 王保全 江涛

 中海石油（中国）有限公司天津分公司，天津 300452

 Tianjin Branch of CNOOC Ltd., Tianjin 300452, China

 位于渤海湾盆地埕北低凸起南侧斜坡区的曹妃甸21￣3构造为馆陶组构造油藏，圈闭主要受断层控制，断层两盘“砂￣砂”对接。分析控制断层的“砂￣砂”对接封闭机理，结果认为，曹妃甸21￣3构造断层封闭机制为断层岩封闭。文中建立了埕北地区泥质体积分数￣排替压力￣深度的关系图版，通过图版定量计算断层岩和储层排替压力之差来确定“砂￣砂”对接含油气构造断层的封闭性，结果表明，控圈断层F1，F2断层岩的排替压力大于储层的排替压力，证明该构造控圈断层具有良好的封闭性。另外，文中还探讨了影响该类含油气构造断层封闭性的控制因素，认为断层岩的排替压力受其泥质体积分数、断面埋深、断层倾角三者共同控制，其中断层岩泥质体积分数和断层倾角的大小是形成封堵的关键因素。

 The Caofeidian 21-3 structure which locates in the Chengbei low uplift, south slope of Bohai Bay Basin is of structural reservoir in Guantao Formation, traps are mainly controlled by faults, the butted joint of sandstones and sandstones in two walls of fault. Analyzing the mechanism of control sealing of sand-sand fault butted joint, we conclude that the sealing mechanism for Caofeidian 21-3 structure is fault rock sealing. In this article, the displacement pressure-depth relation chart with different shale content is established, quantitatively computing the difference between displacement pressure of fault rock and reservoir, the sealing of the sand-sand butt fault is determined, the results show that the displacement pressure of F1&F2 faults which controll the traps is greater than that of the reservoirs, and the faults have good sealing. In addition, the controlling factors of fault sealing for this kind of oil and gas structure was discussed, the fault rock displacement pressure is controlled by the fault rock clay content, section depth and fault dip, of which clay content of fault rocks and fault dip are key factors of the fault sealing.

10.6056/dkyqt201504011