摘要
川西前陆盆地上三叠统须家河组是四川盆地致密砂岩天然气(以下简称致密气)勘探的重要领域,其超压体系的形成与演化对其天然气聚集具有重要影响与控制作用。为了深化川西前陆盆地中生界致密气聚集规律认识与有利勘探区带预测,利用该区气藏压力、钻井液密度资料,以及前人开展的包裹体均一温度研究成果与含烃盐水包裹体PVT模拟气藏古压力恢复成果,结合须家河组不同含气区的埋藏史与构造运动,研究了该区地层流体压力特征、形成机制与演化及其与天然气大规模聚集关系。研究结果表明:①川西前陆盆地须家河组于晚三叠世—侏罗纪形成了欠压实作用超压体系,并在烃源岩成熟度为0.75%时消失或维持弱超压;②晚侏罗世—白垩纪的生烃作用形成了须家河组的古超压体系,其中古超压体系在坳陷带形成于中晚侏罗世,在隆起带及其邻区形成于白垩纪;③燕山期—喜马拉雅期的差异构造运动对须家河组超压体系演化影响十分明显,坳陷带—斜坡带在古近纪超压体系得以维持并略有增强,而隆起带与断裂活动强烈区的超压系统遭受不同程度的破坏;④现今超压体系是生烃与构造挤压联合形成的古超压体系经历强烈构造改造后的残余压力体系;⑤超压体系的持续发育促进了川中地区大面积低丰度天然气区的形成,确保了坳陷带的中北部致密气的大面积封存。结论认为,不仅前陆盆地隆起带及其邻区、坳陷带的川合—绵阳—黎雅以及冲断带—坳陷带为须家河组致密气发育区,而且须家河组超压体系之上的侏罗系—白垩系都具有致密气勘探的良好前景,上述领域均是未来致密气大气田的重要勘探方向。
The Xujiahe Formation of Upper Triassic in the Western Sichuan foreland basin is an important field of tight sandstone gas(here-inafter referred to as tight gas)exploration in the Sichuan Basin.The formation and evolution of its overpressure system has an important influence and control effect on its natural gas accumulation.In order to further understand the natural gas accumulation law in Mesozoic tight sandstone of the Western Sichuan foreland basin and predict the favorable exploration zones,this paper studies the characteristics,for-mation mechanism and evolution of reservoir fluid pressure in this area and its relationship with large-scale natural gas accumulation based on the data of gas reservoir pressure and drilling fluid density in this area,as well as the previous research results of inclusion homogeni-zation temperature and the PVT simulation results of hydrocarbon bearing brine inclusions,combined with the burial history and tectonic movement in different gas bearing areas of Xujiahe Formation.And the following research results are obtained.First,an undercompaction overpressure system was formed in Xujiahe Formation of the Western Sichuan foreland basin during Late Triassic to Jurassic,and then dis-appeared or maintained a weak overpressure when the maturity of source rocks was about 0.75%.Second,the ancient overpressure system of Xujiahe Formation was formed by the hydrocarbon generation of Late Jurassic to Cretaceous.The ancient overpressure system in the de-pression belt was formed in the Middle and Late Jurassic,and that in the uplift belt and its adjacent area was formed in the Cretaceous.Third,the differential tectonic movement of Yanshanian-Himalayan period has a great impact on the evolution of Xujiahe Formation overpressure sys-tem.The overpressure system in the depression belt and the slope belt was maintained and slightly enhanced during the Paleogene period,while that in the uplift area and the strong faulting activity area underwent damage of different degrees.Fourth,the present overpre
作者
李伟
王雪柯
赵容容
唐大海
尹宏
裴森奇
LI Wei;WANG Xueke;ZHAO Rongrong;TANG Dahai;YIN Hong;PEI Senqi(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;Exploration Department,Petro-China Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China;Northwest Sichuan Division,PetroChina Southwest Oil&Gasfield Company,Jiangyou,Sichuan 621741,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2022年第1期25-39,共15页
Natural Gas Industry
基金
中国石油天然气股份有限公司科学研究与技术开发项目“前陆盆地及复杂构造区油气成藏规律与关键技术”(编号:2016B-05)。
关键词
川西前陆盆地
上三叠统
须家河组
致密气
超压体系
大气田
欠压实
生烃增压
超压形成
超压演化
Western Sichuan foreland basin
Upper Triassic
Xujiahe
Tight gas
Overpressure system
Large gas field
Undercompaction
Hydrocarbon-generating pressurization
Overpressure formation
Overpressure evolution
