准噶尔盆地西北缘克82井区佳木河组致密储层沉积相特征及演化

THE TIGHT RESERVOIR SEDIMENTARY FACIES CHARACTERISTICS AND EVOLUTION OF THE PERMIAN JIAMUHE FORMATION IN KE 82 WELL AREA, THE NORTHWESTERN MARGIN OF JUNGGAR BASIN

针对准噶尔盆地西北缘克克82井区佳木河组致密储层岩性变化快、非均质性强的特点,为寻找有利储集相带及提高气藏储量动用程度,运用层序地层学理论、测录井及岩心等资料,认为佳木河组中上段可划分为4个三级层序,主要发育扇三角洲沉积相,伴有火山岩相;研究区受西部构造隆升影响,自下而上水体变浅,物源由西向北不断迁移,地层主体经历了前扇三角洲-扇三角洲前缘-扇三角洲平原的过渡;扇三角洲前缘亚相在SQ2和SQ3的TST时期内最为发育;受区域构造特征和层序格架控制下的有利相带、优质储层分布的影响,研究区北部为天然气富集有利区,水下辫状河道砂体是目前天然气富集的"甜点"。

The tight reservoir of Lower Permian Jiamuhem Formation has rapid changes in lithology and strong heterogeneity in Ke 82 well area of the northwestern margin in Junggar Basin. Based on the characteristic of fast litholog change and strong reservoir heterogeneity,in order to searching favorable reservoir belts and improving the producing degree of reservoir,the sedimentary facies evolution and favorable reservoir development areas are analyzed and predicted with the theory of sequence stratigraphy,core analysis,well logging and other related data. The middle-upper member of Jiamuhem Formation which mainly develops fan delta facies can be divided into 4 third-order-sequences. Affected by the western tectonic bulge,water is shallow gradually from bottom to top,and provenance is migrated continuously from west to north in the research area. The sedimentary evolvement is analyzed to be from pre-fan delta to fan delta front to fan delta plain. The fan delta front dominated sub-facies is exit in the transgressive systems tract of the sequences SQ2 and SQ3. The natural gas accumulation is mainly controlled by favorable facies belt,reservoir and regional structure with influence sequence framework.The favorable area for gas accumulation is in the north of Ke 82 Wells. The underwater braided channel is the dessert for natural gas enrichment zone.