孔雀河斜坡志留系沉积特征及油气分布规律

SEDIMENTARY CHARACTERISTICS OF SILURIAN IN KONGQUEHE SLOPE AND HYDROCARBON DISTRIBUTION LAW

文章旨在通过沉积相的研究,弄清孔雀河斜坡储盖组合,解决长期以来勘探成功率极低,在油气源充足的情况条件下找不到大油气田的问题。利用单井沉积相分析、典型井岩心分析、野外剖面资料和地震测线资料研究结果,得出了塔里木盆地孔雀河地区志留系沉积特点、演化特征及平面展布规律,指出该区在志留纪的沉积是以滨海—浅海为主的海陆过渡相,在北部区域发育有三角洲;结合单井试油试气资料,研究认为该区的浅海沉积物几乎全部是砂岩,缺少泥岩盖层,因而以前所钻4口探井都以失利告终,这也是长期在该区找不到油气田的症结,而孔雀河1井正好钻在位于北部的三角洲沉积区域,该区地层具有砂、泥互层的特点,具备了较好的储集层和局部盖层,试油结果表明有24个气层,该井的东部及东北部的三角洲区域是今后勘探的有利区域。

Through investigating the sedimentary characteristics, evolution and distribution of Silurian in Kongquehe Slope area by use of the sedimentary facies analysis of single well, the core analysis of typical well, the outcrop research and the seismic data, it is pointed out in the paper that the Silurian in the area belonged in transitional facies being mainly composed of littoral-neritic deposits but the delta facies was developed in its north. In combination with the research on the production test data of single well, it was considered that the neritic deposits are almost wholly comprised of sandstones, so this area is lacking in shale caprocks. This is the reason why the four exploration wells drilled defore were all defeated and no oil and gas field was found out in the area for a long time). The well Kongquehe-1, however, was just drilled at the deltaic deposit zone in the north and there are good reservoir rocks and local caprocks in the zone, because of the alternating layers of sand-shale. The production test results indicated that there are 24 gas layers in the well, so that the deltaic deposit zones to the east and northeast of the well are favorable for oil and gas exploration in the future. (Financed by the International Science and Technology Cooperation Program project, No. 2002CB2397, of the Ministry of Science and Technology).