土库曼斯坦阿姆河盆地卡洛夫-牛津阶层序-古地理特征及演化

Sequence-Paleogeographic Characteristics and Evolution of Callovian-Oxfordian in Amu Darya Basin,Turkmenistan

通过沉积相和层序地层分析,确定土库曼斯坦阿姆河盆地中-上侏罗统卡洛夫-牛津阶主要为一套碳酸盐岩台地沉积体系,可划分出SQ1~SQ3三个三级层序,其经历了从缓斜坡台地→镶边缓斜坡台地→缓斜坡台地的沉积演化过程,主力储层、产层发育于SQ1和SQ2层序,此三个层序又可进一步划分为TST和HST两个体系域。以体系域为编图单元,编制了SQ1、SQ2和SQ3层序各体系域的岩相古地理图,并探讨了有利储集相带的展布规律,认为SQ1-HST、SQ2-TST和SQ2-HST三个体系域中叠置发育的台缘礁滩为最有利储层发育的相带,应成为今后的勘探重点。

Based on the studies of the sedimentary facies and sequence stratigraphy,the main sedimentary system of Callovian-Oxfordian of middleupper Jurassic of Amu Darya basin in Turkmenistan is thought to be the carbonate platform. And three third-order sequences( SQ1- SQ3) could be recognized. Callovian-Oxfordian strata experienced the sedimentary evolution from slope ramp to rimmed ramp,and finally to slope ramp. The main reservoirs and producing layers are developed in the SQ1- SQ2,which can be further divided into transgressive systems tract( TST) and Highstand Systems Tract( HST). Taking the system tract as mapping unit,the lithofacies palaeogeography maps for each tract system in SQ1-SQ3 are worked out. By studying the distribution of advantageous reservoirs,the superimposed platform margin reef-bank facies in the HST of SQ1,TST of SQ2,and HST of SQ2 should be the key areas in the future exploration.