川西前陆盆地上三叠统异常高压的分布特征及形成机制研究  

DISTRIBUTIVE CHARACTERISTIC AND FORMING MECHANISM OF ABNORMALLY HIGH PRESSURE IN UPPER TRIASSIC OF WEST SICHUAN FORELAND BASIN

作　　者：刘埃平[1] 文龙[1] 张闻林[1] 孔令霞[1] 

机构地区：[1]中油西南油气田分公司勘探开发研究院

出　　处：《天然气勘探与开发》2004年第4期3-8,共6页Natural Gas Exploration and Development

摘　　要：川西前陆盆地上三叠统异常高压有其特有的分布规律。目前 ,上三叠统异常高压的成因机制归纳起来有以下几种 :欠压实作用 ;生烃增压作用 ;粘土矿物脱水增压作用 ;构造抬升作用。不可否认 ,上述引起上三叠统地层增压的作用在局部范围内客观存在 ,但这几种成因机制难以确切地解释这种异常高压的分布特征 ,有些方面还存在矛盾。通过对上三叠统—侏罗系地层的沉积、成岩作用及构造断裂活动的分析认为 :川西前陆盆地上三叠统地层异常高压的这种分布特征是由两种主要的地质作用所控制 ,一种是中侏罗世沙溪庙组的快速堆积作用 ;另一种是断裂构造活动的释压作用 ,即 ,地层高压是由沙溪庙组最大沉积厚度分布区 (坳陷区 )There is a special distributive pattern for the abnormally high pressure in Upper Triassic of west Sichuan foreland basin. The forming mechanism of Upper Triassic abnormally high pressure currently may be summed up as the following categories: undercompaction, hydrocarbon-generating pressurization, clay mineral dewatering pressurization, and tectonic upwarping. There is no denying the fact that the Upper Triassic stratigraphical pressurization caused by the above-mentioned exists objectively within local limits, but these genetic mechanisms can hardly explain the distributive characteristic of this abnormally high pressure exactly, there exists yet contradiction on some respects. Through analysis to Upper Triassic～Jurassic sedimentation, diagenesis, and tectonic faulting activities, the paper deems that this distributive characteristic of Upper Triassic abnormally high pressure in west Sichuan foreland basin is controlled by two main geologic effects, one is the speedy accumulation of middle Jurassic Saximiao Formation, the other is the pressure release of tectonic faulting activities, i.e: the stratigraphical high pressure is jointly controlled by the maximum thickness distributive area(downwarping area) of Saximiao Formation and the underdeveloping area of faulted structures.

关 键 词：上三叠统 地层 川西前陆盆地 成因机制 断裂构造 分布特征 断裂活动 异常高压 生烃 欠压实作用 

分 类 号：P544.4[天文地球—构造地质学]