摘要
塔里木盆地顺南地区位于卡塔克隆起塔中Ⅰ号断裂下盘北部斜坡区,临近满加尔烃源灶,区域盖层良好,长期处于斜坡,是油气运移的指向区,发育多组北东向断裂,有利于发育储层和油气聚集,具备形成大油气田的油气地质条件。加里东期—海西期多期构造运动控制着奥陶系碳酸盐岩多层系、多类型储层发育。受构造运动和海平面升降的影响,奥陶纪碳酸盐岩经历了多期暴露,具备岩溶储层发育的背景,多期断裂发育有利于表生及深部流体对储层进一步改造形成缝洞型为主储层,储集体发育程度控制了油气聚集规模,断裂带是油气富集的有利区带。通过地球化学分析结果认为顺南地区天然气为干气,成熟度高,成藏期为喜马拉雅期。顺南地区的天然气ln(C1/C2)值变化较大而ln(C2/C3)值变化不大,明显区别于原油裂解成因气。多井包裹体以甲烷气包裹体为主,少见含沥青气相包裹体和沥青包裹体,呈现以干酪根裂解成因气为主。通过钻井测试资料分析,奥陶系碳酸盐岩气藏可能是一个叠合连片含气、具有气柱高度大、受储层非均质性控制的大型缝洞型天然气藏群。
Shunnan area lies in the north slope to the down-thrown blocks of Tazhong No. 1 fault in Katake Uplift,and is adjacent to the hydrocarbon kitchen of Manjiaer Depression. The study area has regionally good cap rocks,and remains a slope for a long geological period,thus it is the main area where hydrocarbons migrate to and accumulate in. Multi-group NE-trending faults developed here were conducive to reservoir development and hydrocarbon accumulation,all such provide the favorable conditions for the formation of large oil and / or gas fields. Multi-period tectonic movements from the Caledonian to Hercynian controlled development of the multilayer and multiphase carbonate reservoirs. With tectonic movements and sea level fluctuations,the Ordovician carbonate rocks experienced multi-period exposure and led to the formation of karst reservoirs. The reservoirs were reconstructed by meteoric water and deep thermal fluids through faults,resulting in fractured-vuggy reservoirs. In brief,reservoirs determined the scale of hydrocarbon accumulation,and the strike-slip faults restricted the hydrocarbon accumulation zones. Geochemical analysis shows that the natural gas is dry gas with high maturity in Shunnan,and its accumulation period was the Himalayan. The natural gas in Shunnan area features in highly variable ln（ C1/ C2） value but low variable ln（ C2/ C3） value,a character obviously differing from that of cracked gas. The inclusions in several wells are dominated by methane gas inclusions,but rare bituminous gas phase inclusions and bitumen inclusions,indicating kerogen cracking origin. Analyses of drilling and test data reveal that the Ordovician carbonate gas accumulation is likely to be a large fractured-vuggy gas reservoir cluster featuring in vertical superimposition,lateral connection,high gas column and strong control of reservoir heterogeneity.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2014年第6期788-797,共10页
Oil & Gas Geology
基金
国家科技重大专项(2011ZX05005-004)
关键词
缝洞型储层
碳酸盐岩
油气富集
奥陶系
顺南地区
塔里木盆地
fractured-vuggy reservoir
carbonate rock
hydrocarbon enrichment
Ordovician
Shunnan area
Tarim Basin
