摘要
中拐地区是准噶尔盆地天然气勘探的重点领域之一,目前在中拐-新光断块佳木河组取得了致密砂岩气勘探的局部突破。通过对致密气样的天然气组分和碳同位素等资料的详细分析,新光地区致密砂岩气组分以甲烷为主,含量达91.79%,干燥系数均值为0.96,为干酪根裂解气类型,属于较高热演化程度的干气;该区气样δ^(13)C_1值均小于-30‰,δ^(13)C_2分布范围为-32.56‰^-26.79‰;总体具有正碳同位素序列特征,在有机热成因基础之上佳木河组致密砂岩气主要为自源型的煤成气和它源型的油型气混合而成;整体表现为成熟-高成熟的煤成气和偏煤型混合气。根据成熟度推算及源岩发育特征,认为煤成烷烃气来自佳木河组,油型烷烃气来自风城组,其中以佳木河组腐殖型源岩的贡献为主。结合致密砂岩气成藏条件综合分析,研究区可能难以形成天然气富集的大气区,但仍有发育局部富气的"甜点区"潜力。
Zhongguai area is one of the key areas of Junggar Basin natural gas exploration,and the tight sandstone gas exploration achieved local breakthrough in the Jiamuhe Formation of Xinguang Fault-Block at present. The components and carbon isotope data of tight gas are analyzed detailedly. The tight sandstone gas is dominated by methane with content up to 91.79%. It belongs to dry gas with average dry coefficient of 0.96 and kerogen-cracked gas. δ^(13)C_1 values of gas samples were are lower than -30‰. δ^(13)C_2 distribution range is -32.56‰^-26.79‰. The majority of the samples is characterized by positive carbon isotope series. In adition to the biogenic origin,the Jiamuhe tight sandstone gas mainly consists of self-sourced coal-derived gas and other-sourced oil-associated gas in the mature-high mature stage. According to the reckoning maturity and source rock development characteristic,the coal-derived alkane gas is from source rock of the Jiamuhe Formation,and the oilformed gas is from source rock of the Fengcheng Formation. And with comprehensive analysis of tight sandstones gas accumulation condition,the study area is difficult to form the natural gas enrichment region,but has potential of forming local-enrichment region in'Sweet spot'.
出处
《新疆石油天然气》
CAS
2017年第3期6-10,1,共5页
Xinjiang Oil & Gas
关键词
准噶尔盆地
佳木河组
致密砂岩气
成因类型
气源
Junggar Basin
Jiamuhe Formation
Tight sandstone gas
genetic type
gas source
