四川盆地雷四3亚段油气勘探方向

近年来,中石油和中石化在四川盆地雷口坡组雷四³亚段的勘探陆续取得重要进展,展示了良好的勘探前景。笔者结合新钻探井和最新研究成果,从地层、沉积相、烃源岩、储层和成藏等多方面采用烃源对比、埋藏史及烃源岩热演化史、包裹体测温等方法对四川盆地雷四³亚段的含油气地质条件进行了进一步分析,总结了其油气成藏特征,提出了有利勘探区带,以期有助于拓展四川盆地雷口坡组的勘探领域。研究结果表明:雷四³亚段天然气以雷口坡组和须家河组烃源岩混合来源气为主;储集空间以粒间溶孔、晶间溶孔为主,属低孔低渗储层;雷四³亚段气藏为2期成藏,烃源岩于中、晚侏罗世进入生烃高峰;雷四³亚段具有构造和构造-岩性地层2种气藏类型,龙门山山前断褶带为构造气藏的有利勘探区,新津-邛崃斜坡带与梓潼-盐亭斜坡带是构造-岩性地层气藏的有利勘探区。

OIL AND GAS EXPLORATION DIRECTIONS IN THE T2l34 OF THE SICHUAN BASIN

In recent years,CNPC and Sinopec have made significant progress in oil and gas exploration in the T₂l₃⁴ of the Sichuan Basin with good prospects.Based on new drilling wells and the latest research results,methods of hydrocarbon sources correlation,burial history,thermal evolutionary history of source rocks,and temperature measurement of inclusions are adopted for analysis of stratigraphy,sedimentary facies,source rocks,reservoirs,and accumulations.The petroleum geological conditions of the T₂l₃⁴ sub-section in the Sichuan Basin is further analyzed,and their hydrocarbon accumulation characteristics summarized.Then favorable exploration zones are proposed to help expand the exploration area of the Leikoupo Formation in the Basin.The research results suggest that the natural gas of the T₂l₃⁴ is dominated by mixed source rocks of the Leikoupo Formation and Xujiahe Formation;the reservoir space is dominated by intergranular and intergranular dissolved pores,which are low in both porosity and permeability;the T₂l₃⁴ subsegment gas reservoir is a two-stage accumulation,and the source rocks have approached the peak of hydrocarbon generation during the middle and late Jurassic.There are two types of gas reservoirs in the T₂l₃⁴ segment:the tectonic and lithologic.The Longmenshan piedmont fault zone is a favorable exploration area for structural type of gas reservoirs.Both the Xinjin-Qionglai slope and the Zhitong-Yanting slope are favorable exploration areas for structural and lithologic type of gas reservoirs.