川西北部河湾场气田天然气地球化学特征及其气源探讨  

Geochemical behaviors and gas origins in the Hewanchang Gas Field,northern part of the Western Sichuan Basin

作　　者：黄东[1] 戴鑫[2] 戴赟[2] 朱永刚[3] 杨毅[3] 裴森奇[3] 

机构地区：[1]中国石油西南油气田公司勘探开发研究院 [2]西南石油大学 [3]中国石油西南油气田公司川西北气矿

出　　处：《天然气工业》2011年第3期37-40,109,共4页Natural Gas Industry

基　　金：四川省高校天然气地质重点实验室基金项目(编号:2006SZD044)

摘　　要：位于川西北部的河湾场气田为多烃源、多储层、多产层的复合型气田,由于过去勘探开发的主要对象为浅层陆相天然气,对其深层天然气成因和气源还未做过系统研究。为此,根据河湾场地区以及邻区的天然气组分、天然气碳同位素和天然气浓缩烃资料,结合区域烃源岩和储层沥青分析资料,研究了该气田天然气的地球化学特征及其气源。结果表明:各地质层位的天然气均表现为不含硫化氢的干气特征;其中奥陶系、二叠系天然气的碳同位素特征与川东石炭系天然气特征极为相似,且天然气具有原油二次裂解气的特征,根据该区储层沥青的分布规律,认为奥陶系、二叠系天然气来源于志留系;而下三叠统飞仙关组天然气则源于二叠系碳酸盐岩油型气与上二叠统吴家坪组煤成气的混合气。The Hewanchang Gas Field located in the northern part of the Western Sichuan Basin is a complex gas field with diversified hydrocarbon origins,various reservoirs and multiple pay zones.The previous gas exploration and development mainly focused on shallow continental gas reservoirs so no systematic research has been carried out on the genesis and origins of gas in the deeper reservoirs there.In view of this,we studied the geochemical behaviors and sources of gas in this field based on various data including gas composition,carbon isotope and hydrocarbon condensate and in combination with regional source rocks and bitumen distribution in the reservoirs.Gases in all the reservoirs are dry gas without H2S.The carbon isotopes of gases in the Ordovician and Permian reservoirs show very similar characteristics with Carboniferous reservoirs in the Eastern Sichuan Basin.Moreover,the gases there show certain characteristics of oil-cracked gas.Based on the wide distribution of bitumen in the reservoirs in the study area,it is believed that the gases in the Ordovician and Permian are sourced from the Silurian,while the gas in the Lower Triassic Feixianguan Formation is a mixture of oil-type gas from the Permian carbonates and the coal-derived gas from the Upper Permian Wujiaping Formation.

关 键 词：天然气组分 碳同位素 浓缩轻烃 原油二次裂解气 气源对比 天然气成因 河湾场地区 四川盆地 

分 类 号：P618.13[天文地球—矿床学]