川中—川南过渡带上三叠统天然气聚集的储渗体圈闭模型

RESERVOIR-PERMEATION SYSTEM TRAP MODELS FOR GAS ACCUMULATION OF THE UPPER TRIASSIC IN THE INTERMEDIATE ZONE BETWEEN THE CENTRE AND SOUTH OF SICHUAN BASIN

川中—川南过渡带上三叠统香溪群中,已发现两个气田和一些含气小区。这里背斜和断层稀少,圈闭情况不清。通过对该群储层特征、沉积相、成岩作用、香溪群沉积前古构造地貌、香溪群与下伏层断层变形差异及气藏特征等的研究,认为有四类有利于天然气聚集的储渗体圈闭,并绘制了较理想的模型。它们是:与香溪群沉积前古地貌有关的储渗体圈闭;沉积相变储渗体圈闭;成岩相变储渗体圈闭;断层转化调节的储渗体圈闭。共四类九种类型。储渗体圈闭气藏在本区具较好勘探前景,但因其具隐蔽性和复杂性,还需加强对它的研究和地震识别工作。

Two gas fields and some small gas -bearing areas are discovered in Upper Triassic intermediate zone between the centre and south of Sichuan Basin. But there is few anticlines and faults in the zone and the conditions of the traps are not clear. By rerearching the reservoir characteristics,sedimentary facies, diagenesis, palaeostructure, palaeogeomorphology and deformation discrepaces of the underlying faults in the area,it is determined that there are four types of reservoir-permeation system traps favourable for gas accumulation in the Upper Triassic and the relevant idealer models are set up. They are: ①the reservoir-permeation system traps related to the palaeogeomorphology,②the ones with sedimentary facies changes, ③the ones with diagenetic facies changes, ④the ones converted from faults. Moreover,they are classified into nine types of secondary reservoir-permeation system traps with good exploration potential.