江汉盆地潜江凹陷潭口地区潜江组盐构造类型及成因机制探讨

    DISCUSSION ON THE SALT STRUCTURE TYPES AND GENETIC MECHANISM OF QIANJIANG FORMATION IN QIANJIANG DEPRESSION, JIANGHAN BASIN

    • 摘要: 潜江凹陷位于江汉盆地的中部,潭口油田靠近潜北大断层.通过勘探开发,根据测、钻井资料及生产动态数据发现,该区地层厚度在短距离内发生较大变化,砂体间的侧向连续性差,范围小.该地区盐岩十分发育,根据地震剖面以及盐层的发育,分析该地区产生一系列盐构造的类型,分别有盐层滑脱带以及滑脱断层、盐隆构造、盐辟构造等几种类型.该地区的盐构造的成因机制主要为走滑作用,根据盐构造的类型,成因机制可分为盐层滑脱作用、盐层隆升作用以及盐层刺穿作用.将盐构造的演化分为3个阶段,分别为荆沙组盐构造孕育期、潜江组潜四-潜三段盐构造生成期、潜江组潜二段-荆河镇组盐构造定型期.盐岩的发育以及盐构造的形成,在一定程度上导致目的层砂体侧向连续性差,油层展布范围小,对油气成藏产生影响.

       

      Abstract: The Qianjiang Depression is located in the central part of Jianghan Basin with Tankou oilfield close to the Qianbei fault. Through exploration and exploitation, it is found that the formation thickness varies greatly in a short distance with poor lateral continuity and narrow distribution range between sand bodies according to the logging, drilling and production performance data. As the salt rocks are well developed in the area, the types of a series of salt structures including salt bed detachment zone, detachment fault, salt dome and salt diapir structures are analyzed based on the seismic section and development of salt bed. The genetic mechanism of salt structures in the area is dominated by strike-slip. According to the salt structure types, the genetic mechanism can be recognized as salt bed detachment, uplift and diapirism. The evolution of salt structure is divided into three stages:the incubation period of salt structure in Jingsha Formation, the formation period of salt structure in Eq4-Eq3 of Qianjiang Formation, and the finalization period of salt structure in Eq2-Jinghezhen Formation. The development of salt rocks and formation of salt structures lead to the poor lateral continuity of target sand body and small distribution range of oil layer, thus exerting an effect on the oil-gas accumulation.

       

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