摘要
乐东气田是莺歌海盆地乐东区中—浅层大型气田,其气藏类型为底辟穹隆背斜控制的构造—岩性气藏。为研究其底辟构造特殊的天然气富集模式,分析了该区天然气的成藏条件:乐东22-1/15-1气田所属构造位于中央坳陷带生烃凹陷内,烃源条件优越,底辟上拱为天然气聚集提供了富集场所,同时深部高压型复式地温—地压系统又为天然气向浅部正常温压系统运移提供了动力,天然气沿着与底辟活动有关的断裂—微裂隙垂向运移至浅部滨海砂岩和风暴砂岩储层中。在此基础上,根据该区底辟构造与天然气的空间配置关系,结合生烃动力学、碳同位素动力学等研究方法,探讨了该区底辟构造与天然气富集的关系。结果表明:①底辟构造决定了天然气的空间配置关系,天然气聚集在底辟成藏条件配置好的顶部及两侧的构造、岩性圈闭中;②底辟构造的发育演化过程与油气生成及运聚成藏等均具有成因联系和耦合关系。结论认为:该区的天然气藏为晚期富集,具有多源混合—幕式成藏的特点;其油气充注过程可分为3期,与底辟构造的期次幕式活动相匹配。
Ledong 22 1/15-1 are two large medium to-shallow gas fields of structural-lithological type controlled by diaper dome anti clines. In order to understand its unique gas accumulation patterns of the diaper structure, we analyzed the gas play conditions in the study area. The structure in which the Ledong 22 1 and 15 1 gas fields occur is located in the hydrocarbon kitchen of the central de pression with favorable source rock conditions and the diapiric rising providing space for gas accumulation. The deep high-pressure composite geotemperature-geopressure system drives gas migration into the shallow normal temperature-pressure system. Then, natural gas migrates vertically along the faults and microfractures related to diapiric rising into shallow littoral sandstone and tempes- tite reservoirs. According to the spatial combination of the diaper structure with natural gas reservoirs, and adopting such research methods as kinetics of hydrocarbon generation and carbon isotopes, this paper discussed the relationship between the diaper structure and gas accumulation. On one hand, the diaper structure determines the spatial combination of natural gas which accumulates in the structural lithological traps on the top and two sides of the diaper structure. On the other hand, the development and evolution of the diaper structure has the genetic linkage and a coupling relation with hydrocarbon generation, migration and accumulation. It was con cluded that the gas reservoirs in the study area are featured by late enrichment, mixed sources and episodic accumulation, and that the hydrocarbon accumulation process can be divided into 3 stages which corresponds with the episodic activity of the diaper struc ture.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2013年第11期16-21,共6页
Natural Gas Industry
基金
国家科技重大专项课题(编号:2011ZX05023-004-02)
关键词
莺歌海盆地
乐东22
1
15
1气田
成藏条件
富集模式
底辟构造
幕式活动
断裂一微裂隙
碳同位素值
Yinggehai Basin, Ledong 22-1 and 15-1 gas fields, gas play, accumulation pattern, diaper structure, episodic activity, fault, microfracture, carbon isotope
