扬子地块中、新生代构造演化对海相油气成藏的制约

扬子地块中、新生代宏观构造演化和动力学的差异制约着中、古生界海相油气成藏。通过对扬子地块印支期以来构造演化的分析和扬子地块不同段典型油气藏的解析,显示差异的构造演化造成扬子地块不同段的主要烃流体源、保存环境和成藏演化的不同。上扬子地块的烃流体源以油裂解气和干酪根裂解气为主,海相地层中整体封闭环境发育,存在古油藏—早期气藏—晚期气藏的成藏演化系列,具有早期成藏、后期转化、晚期聚气的成藏模式。中、下扬子地块的烃流体源主要为二次生烃和海相早期原生油气源,在陆相地层与海相地层中均存在封闭体系,具有反复的成藏、改造、成藏、破坏的成藏演化过程,在断陷反转区具有下生上储、原生残余油气藏以及二次生烃等成藏模式,而在反转断块区可能的成藏模式包括原生残余成藏和晚期次生成藏。

Constraint of Meso-Cenozoic tectonic evolution of Yangtze massif on formation of marine reservoirs

Mesozoic and Paleozoic marine reservoirs are controlled by the difference between Meso-Cenozoic macroscopic tectonic evolution and dynamics of Yangtze massif. Analyses of the tectonic evolution of Yangtze massif since Indosinian epoch and the typical oil and gas reservoirs in different segments of Yangtze massif show that differential tectonic evolution has resulted in the different major sources of hydrocarbon fluids, preservation conditions and reservoiring evolution in different segments of Yangtze massif. The sources of hydrocarbon fluids in the Upper Yangtze massif are mainly of cracking gas cracked from oil and kerogen. Completely enclosed environment is developed in marine formations. The reservoiring evolution series include the formation of fossil oil reservoir, early gas reservoir and late gas reservoir, and the reservoiring pattern is early reservoir formation-later transformation-late gas accumulation. The sources of hydrocarbon fluids in Middle and Lower Yangtze massifs are mainly of secondary hydrocarbon generation and early primary oil and gas sources in marine strata. Enclosed systems occur in both continental and marine strata. The reservoiring evolution process is exactly the process of repeated reservoiring, reformation, reservoiring and destruction. The reseroviring patterns in the re- versed area of fault depression include reservoirs occurring above the source rocks, residual primary reservoirs and secondary hydrocarbon generation, while that in reversed fault block areas include residual primary reservoirs and late secondary reservoirs.