深层-超深层碎屑岩优质储层成因机理

Genetic mechanisms of high-quality deep to ultra-deep clastic reservoirs： A case study of the Permian-Triassic strata in the hinterland of the Junggar Basin

王继远 王斌 胡宗全 商丰凯 刘德志 李振明 邱岐 宋振响 胡志啟

Jiyuan WANG Bin WANG Zongquan HU Fengkai SHANG Dezhi LIU Zhenming LI Qi QIU Zhenxiang SONG Zhiqi HU

为了揭示准噶尔盆地腹部深层-超深层碎屑岩优质储层成因机理，利用盆地腹部地区最新钻井资料及岩心样品，通过铸体薄片、扫描电镜、能谱和包裹体分析以及XRD等测试方法，对二叠系上乌尔禾组和三叠系百口泉组与克拉玛依组储层成因进行研究。结果表明：成岩演化差异控制了原生孔隙和次生溶蚀孔隙的发育。克拉玛依组经历了压实、绿泥石包壳式胶结、长石/火山岩岩屑溶蚀、硅质胶结、自生伊利石沉淀以及晚期方解石胶结，其中绿泥石包壳是原生孔隙保存的最主要成岩矿物；上乌尔禾组经历了压实、绿泥石充填式胶结、浊沸石胶结、浊沸石/长石/火山岩岩屑溶蚀、硅质胶结、自生伊利石沉淀以及晚期方解石胶结，其中早期浊沸石胶结以及浊沸石、长石和火山岩岩屑酸性溶蚀是次生孔隙发育的关键成岩作用。受浅水辫状河三角洲前缘水下分流河道高能相带强水动力淘洗，储层原始孔隙结构优越，与早成岩期的绿泥石包壳及强超压共同控制原生孔隙的保存。中-基性火山岩岩屑水化蚀变成因的高硬度浊沸石早期胶结，抵抗了快速深埋阶段的压实减孔。多期生烃酸性流体伴随超压传递促进硅铝酸盐矿物溶蚀增孔。低地温背景下，上乌尔禾组-百口泉组仍处于中成岩A-B期，减缓了成岩演化进程，有效孔隙发育的下限深度增加。

This study aims to reveal the genetic mechanisms underlying high-quality deep to ultra-deep clastic reservoirs in the hinterland of the Junggar Basin. Using the latest drilling data and core samples from the hinterland， as well as data from casting thin section observations， scanning electron microscopy （SEM）， spectral analysis， inclusion analysis， and X-ray diffraction （XRD） analysis， we investigate the origins of reservoirs in the Permian Upper Urho Formation and the Triassic Baikouquan and Karamay formations. The results indicate that differential diagenetic evolution governs the development of primary pores and secondary dissolution pores. The Karamay Formation underwent compaction， chlorite coating cementation， dissolution of feldspar/volcanic detritus， siliceous cementation， authigenic illite precipitation， and the late-stage calcite cementation sequentially， during which chlorite coatings emerged as the most significant diagenetic mineral for the preservation of primary pores. In contrast， the Upper Urho Formation experienced compaction， chlorite filling cementation， laumontite cementation， dissolution of laumontite/feldspar/volcanic detritus， siliceous cementation， authigenic illite precipitation， and the late-stage calcite cementation in sequence. The early-stage laumontite cementation and acid dissolution of laumontite/feldspar/volcanic detritus， among others， play a critical role in the formation of secondary pores. In the subaqueous distributary channels at the front of the shallow braided river delta， the strong hydrodynamic elutriation in high-energy facies zones results in superior primary pore structures in these reservoirs. This， combined with early-stage chlorite coatings and significant overpressure， collectively contributes to the preservation of primary pores. The early-stage cementation of high-hardness laumontite formed by the hydrothermal alteration of intermediate-mafic volcanic detritus resists the compaction and porosity reduction in the rapid deep burial stage. The acidic fluids from multi-stage hydrocarbon generation and overpressure transfer jointly accelerate the dissolution of aluminosilicate minerals and porosity enhancement. Under the background of low geotemperature， the Upper Urho-Baikouquan formations remain in middle diagenetic stages A and B， which has slowed down the diagenetic evolution and increased the lower depth limit for effective porosity development.

10.11743/ogg20250111