基于岩石物理相的砂砾岩储层分类评价--以准噶尔盆地玛131井区块百二段为例

勘探实践表明,准噶尔盆地玛北斜坡主力油层段百二段砂砾岩储层非均质性强,孔隙结构差异大,需要综合影响储层的各种地质因素对其进行分类评价。利用岩芯、薄片、钻测井、物性、工业CT等资料,对准噶尔盆地玛北斜坡玛131井区块百二段砂砾岩储层沉积相、成岩相、裂缝相特征进行了研究,在此基础上分析了百二段储层岩石物理相,并基于岩石物理相对储层进行分类评价,预测有利储层发育区。通过沉积微相、成岩相的叠加聚类,对研究区百二段砂砾岩储层岩石物理相进行分类,划分出水下分流河道-不稳定组分溶蚀等岩石物理相;按照沉积相、成岩相对储层孔隙结构的建设与破坏作用归纳出3大类岩石物理相。依据三类岩石物理相将储层划分为3类,并结合压汞、薄片、CT、产能等资料进行表征与评价,其中一类和二类岩石物理相储集性能较好,三类岩石物理相为致密遮挡层。最后以亚段为单位,对百二段岩石物理相进行平面成图,预测有利储层分布区。

Reservoir Evaluation of Sand-conglomerate Reservoir Based on Peteophysical Facies: A case study on Bai 2 reservoir in the Ma131 region,Junggar Basin

The petroleum exploration of Junggar Basin shows that there exist serious heterogeneity in Bai 2 reservoir of Mabei region, and it is necessary to identify the types of reservoir in consideration of a mass of geological factors that influence reservoir quality. Using core observation, thin section, logging and drilling data, physical property data, CT data, etc., the sedimentary facies, diagenetic facies and fracture facies of the Upper Triassic Baikouquan Formation Member 2 (Bai 2) reservoir in the Ma 131 region were studied. On this basis, the petrophysical faices of Bai 2 layers were examined to evaluate the pore structure by classification and predict zones with high porosity and permeability. The petrophysical facies were divided according to the superposition and combination of sedimentary facies, diagenetic facies. A number of petrophysical facies of Bai 2 layers such as underwater distributary channel, dissolution of unstable components, were identified in this way. Three main categories of petrophysical facies were summed up according to the constructive and destructive impact of sedimentary facies, diagenetic facies on the reservoir property and pore structure of Bai 2 layers. According to three petrophysical facies, the reservoir of Bai 2 can be divided into three categories. Based on mercury injection data, casting thin section, CT data and oil capacity data, reservoir of each categories was characterized and evaluated. At last, the horizontal distribution of different petrophysical facies were mapped, and it can be used to predict the beneficial zones.