中文摘要：

川西坳陷中段上三叠统须四段经历了复杂的成岩作用以及强烈的构造演化,导致了天然气藏成藏的多期性,决定了天然气聚集和分布的复杂性。因此,对川西坳陷中段须四段天然气藏成藏期次的研究一直是勘探领域研究的重点,至今尚未取得统一的认识。通过采集新场、成都凹陷、中江—回龙、龙门山前、知新场不同构造单元重点井砂岩样品进行包裹体测试分析,并对须四段上、下2个亚段进行成藏期次的系统研究。对包裹体基本特征镜下观察及均一温度埋藏史—热史图投点的研究表明：川西坳陷中段须四下亚段为一期成藏,主要在早—中燕山期便进行了大规模的天然气充注,且后期得到了较好的保存;须四上亚段具有2期成藏的特征,早期成藏发生在早—中燕山期,但大都经过后期的改造,此后在早喜马拉雅期再次进行天然气充注,即第二期成藏。通过对晚侏罗世、早白垩世川西须四段古构造分析,进一步明确了燕山期、喜马拉雅期古构造对川西坳陷各构造单元须四段天然气聚集和分布的控制作用。

英文摘要：

The middle part of Western Sichuan Depression has undergone complex diagenesis and strong tectonic evolution,which controlled the complex progress of gas filling and occurrence.So the T_3x_4 hydrocarbon accumulation timing is an important exploration consideration and a difficult task.Sandstone samples were collected from key wells of five different tectonic units：Chengdu Sag,Xinchang,Zhongjiang-Huilong,Longmenshanqian and Zhixinchang tectonic zone.On the basis of the fluid inclusion analysis,we completed a systemic study of the hydrocarbon accumulation period of two sub-sections of T_3x_4,the upper and lower T_3x_4.The timing is constrained by the fluid inclusion types and the setting points of homogenization temperatures on a burial and thermal history diagram.This study shows that the lower T_3x_4has experienced only one period of hydrocarbon accumulation,which mainly happened in the early-middle Yanshanian.That natural gas charge has a good preservation through later geological time.For the upper T_3x_4,there are two different periods of hydrocarbon accumulation：the earlier one is early-middle Yanshanian,but in the later period,much of the reservoir has been modified,and then refilled in the early Xishanian.The study about the paleotectonics evolution of the Late Jurassic and Early Cretaceous rocks,further explains the constraint of the geological movement during the Yanshanian and Xishanian upon the T_3x_4 gas accumulation and distribution.