利用流体包裹体确定川西坳陷孝泉-丰谷构造带须家河组天然气成藏期  

Determination of the time of gas accumulation in the Xujiahe Formation of Xiaoquan - Fenggu structural belt in theWestern Sichuan Depression through fluid inclusion analysis

作　　者：冷济高[1] 李书兵[2] 杨长清[3] 

机构地区：[1]中国石化西南油气分公司博士后科研工作站 [2]中国石化西南油气分公司 [3]青岛海洋地质研究所

出　　处：《天然气工业》2011年第8期38-42,131,共5页Natural Gas Industry

摘　　要：孝泉—丰谷构造带是川西坳陷前陆盆地上的一个次级构造单元,天然气资源非常丰富,构造运动的多期性致使天然气成藏过程复杂,研究该区天然气成藏期,对于明确天然气成藏模式、富集规律及成因机制具有重要的意义。为此,整理、分析了该区13口井81个样品的666个流体包裹体测试数据,并在埋藏史分析的基础上对油气成藏期进行了厘定。结果表明:①上三叠统须家河组四段在地史时期至少经历了4期成藏,须二段则经历了至少6期成藏;②须二段和须四段都有液态烃充注,时期分别为T3x5—J1和J1—J2早期,气态烃充注起始时间分别为J2中期、J2晚期,止于K2期;③丰谷、合兴场地区须二段的成藏期早于新场地区,合兴场地区须四段的含烃流体包裹体丰度低,成藏特征不明显;④须二段气藏具有"先致密,后成藏"的特点,为深盆气藏,而须四段气藏则表现为常规气藏特征。The Xiaoquan Fenggu structural belt is a secondary structural unit in the foreland basin in the Western Sichuan Depression where gas resources are abundant. However, multiple stages of tectonic movements made the gas accumulation process complicated. A study on the time of gas accumulation stages is of great significance for determining gas accumulation models, gas enrichment patterns, and genetic mechanism. Test data of a total number of 666 fluid inclusions from 81 samples of 13 wells are collected and analyzed, and the time of each gas accumulation stage is determined based on the burial history of this study area. The following results are obtained. (1) Gas accumulation in the 4th member of the Upper Triassic Xujiahe Formation occurred at least in 4 stages in the burial history, while that in the 2nd member occurred at least in 6 stages. (2) Both the 2nd and 4th members have liquid hy drocarbon charged at T3x5-J1 and early J1-J2 respectively, while their gaseous hydrocarbon charging initiated at middle J2 and late J2 respectively and ended in K2. (3) For the 2nd member of the Xujiahe Formation, hydrocarbon accumulation in the Fenggu and Hexingchang areas was earlier than that in the Xinchang area. The 4th member in the Hexingchang area contains a low abundance of fluid inclusions and its hydrocarbon accumulation characteristics are not clear. (4) The gas reservoirs in the 2nd member of the Xujiahe Formation are basin centered gas reservoirs featured by 'early tight reservoir forming and late hydrocarbon accumulation'. In contrast, the gas reservoirs in the 4th member are of conventional features.

关 键 词：流体包裹体 成藏期次 成藏时间 晚三叠世 深盆气 埋藏史 孝泉-丰谷构造带 川西坳陷 

分 类 号：P618.13[天文地球—矿床学]