THE CAMBRIAN SEQUENCE STRATIGRAPHY FRAMEWORK AND SOURCE-RESER-VOIR-CAP ROCK ASSOCIATION OF BACHU UPLIFT IN TARIM BASIN

Based on comprehensive analysis of the outcrops,wells data,seismic explanation data,and guided with sequence stratigraphy theory,the sequence stratigraphy of Bachu Uplift Cambrian is divided into fourteen 3rdorder sequences and three 2nd-order sequences which belong to type I sequence and were constituted by TST and HST. In the Cambrian period,the sedimentary environment is mainly showed as alternating deposition of restricted platform-evaporation platform,the water depth is mainly showed as the northwestern margin is relatively deep and the southeast is shallow. On the basis of above,this paper discusses the characteristics of source-reservoir-cap rock and its rule of combination on the basis of sequences stratigraphic framework,the results show that there are 1 set of source rock,3 sets of reservoir and 2 sets of cap developed in the Cambrian in the study area. The source rock is SS1 HST,reservoirs are SS1 HST,SS2 TST,SS3 TST and HST,caps are SS1 HST,SS2 HST. They combined into 2 sets of good source-reservoir-cap rock assemblages. In addition,most dolomites in the outcrops or in the drill core have been changed by hydrothermal,and the greater intensity of hydrothermal alteration,the more developed dissolution pores. Therefore,in some of the places where intense tectonic activities happened,hydrothermal then began to change the rock by migration. At last,it formed good reservoirs.