四川盆地凉高山组层序地层格架及有利勘探区优选

Establishment of Sequence Stratigraphic Framework and Optimization of Favorable Exploration Areas of Lianggaoshan Formation,Sichuan Basin

针对四川盆地凉高山组层序地层格架的建立及有利区优选复杂多变的难题,利用四川盆地凉高山组测井及地震等资料,识别不同尺度的标志层,建立标志层的测井-地震识别标准,利用区域格架线搭建层序地层格架,通过井震结合分析,厘清全盆地凉高山组岩性、相带变化关系,并结合有利相带分布及“源储”配置关系,优选有利勘探区。研究表明:以水进界面作为标志层,搭建层序地层格架,能够快速确定烃源岩与储层发育层位、厚度及分布范围;优选凉高山组凉一3亚段为有利烃源岩发育层位,凉二1亚段为有利储层发育层位;凉一3亚段烃源岩发育区,即盆地东北部及边缘龙岗-梁平一带页岩厚度较大,最厚处可达60~80 m,是下一步勘探的有利目标区。研究成果丰富了四川盆地凉高山组层序地层、沉积演化及勘探区优选等相关勘探研究工作,也为同类油藏的勘探开发提供了理论依据。

In view of the complex and various problems in the establishment of sequence stratigraphic framework and the optimization of favorable areas in Lianggaoshan Formation,Sichuan Basin,according to the logging and seismic data of Liangshan Formation,the marker beds of different scales were identified,a logging-seismic identification standard was established for the marker beds,a sequence stratigraphic framework was constructed with regional grid lines,the relationship between lithology and facies zone changes of Lianggaoshan Formation in the whole basin was clarified by the combined analysis of seismic trace and well logging data,and the favorable exploration areas were determined according to the distribution of favorable facies zones and the relationship of"source and reservoir".The study shows that after the water entering horizon was regarded as the marker bed and the sequence stratigraphic framework as established,the development horizon,thickness and distribution range of source rock and reservoir could be quickly determined.Submember 3,Member 1 of Lianggaoshan Formation was regarded as the horizon favorable for source rock development,Submember 1,Member 2 of Lianggaoshan Formation regarded as the horizon favorable for reservoir development,and Submember 3,Member 1 of Lianggaoshan Formation regarded as the source rock development area,namely in the northeast of Sichuan Basin and the edge of Longgang-Liangping Area,with a maximum shale thickness of 60~80 m,which was a favorable target area for further exploration.The results of the study have enriched the sequence stratigraphy,sedimentary evolution and exploration area optimization of Lianggaoshan Formation,Sichuan Basin,and also provided theoretical basis for the exploration and development of similar reservoirs.