东濮凹陷沙三段盐丘浅析

An approach to the formation of salt domes in Dongpu sag.

根据东濮凹陷文留地区L12 3 8测线、L14 76测线、L15 85测线具有盐丘地震反射的大部分特征 ,结合过测线的文 19井、文69井、文 64井、文 2 18井的实钻沙三段盐岩资料 ,认为东濮凹陷存在盐丘。盐丘的成因是 :在密度倒转而产生的浮力作用下 ,东濮凹陷西部洼陷带、东部洼陷带深部发育的沙三段盐岩沿文西断层、文东断层的断层面 ,由洼陷深部位向上流动 ,断层下降盘的差异压实促进了盐岩塑流上拱 ,刺穿上覆层形成盐丘。东濮凹陷盐丘之上及两侧发现油层 ,之下发现东濮凹陷最大的文2 3气田。文 2 18井所钻盐丘的沙三2 盐及其下的沙三3 段砂泥岩、右侧的沙三4盐及致密的中生界、古生界和文西断层共同组成了有利的油气圈闭。文留地区还有许多与盐丘有关的未知圈闭待发现 ,勘探前景比较乐观。图 2参

From the analysis results of seismic reflection charac ters of seismic lines of L1238, L1476 and L1585 in Wenliu block of Dongpu sag an d combined with the drilling data of S 3 salt rocks from Wells Wen19, Wen69, We n64 and Wen218, it can be clearly seen that there really exist salt domes in Don gpu sag. The origin of the salt domes is that due to the action of the buoyancy created by the reverse of the gravity flow, which caused the S 3 salt rocks dev eloped in the deep parts of western and eastern Dongpu sag, moving upward along the fault planes of the Wenxi and Wendong faults and to the differential compact ion, which promoted the salt rocks arching upward and piercing the overburden to form salt domes. At present, oil and gas reservoirs are found above, below and beside the salt domes. The authors consider that the salt rocks of S 3 2 drill ed by Well Wen218, the sandstone and mudstone of S 3 3 and in the right salt o f S 3 4, the tight Mesozoic and Paleozoic Groups, and the Wenxi fault form tog ether a favorable oil and gas trap belt, and there may be many undiscovered oil/ gas traps related to salt domes in Wenliu region, indicating a positive explorat ion potential.