岩石物理相在砂砾岩储层分类评价中的应用——以M1井区上乌尔禾组为例

玛湖凹陷M1井区上乌尔禾组砂砾岩储层非均质性强,孔隙结构和试油产能差异大,主控因素不明.利用岩心、薄片、测录井及试油等资料,对M1井区上乌尔禾组的沉积相、成岩相、裂缝相以及储层综合分类展开研究.结果表明,扇三角洲砂砾岩储层主要为重力流及牵引流2种成因类型,对应扇面河道、水下分支河道、泥石流3种沉积微相.可识别出弱成岩作用相、溶蚀相、压实致密相、方解石胶结相4种成岩相.沉积相与成岩相是影响该区储层的主控因素,依此将储层分为水下分流河道-弱成岩作用相、水下分流河道-溶蚀相、扇面河道-弱成岩作用相、扇面河道-溶蚀相、泥石流-压实致密相、砂砾岩方解石胶结成岩相6种岩石物理相.依据沉积相和成岩相对于储层的影响,将6种岩石物理相归纳为3种类型储层,其中Ⅰ类和Ⅱ类储层最好,Ⅲ类储层最差,胶结致密.该区岩石物理相与试油结果匹配好,可有效预测有利储层分布区.

Application of petrophysical facies in sandy-conglomerate reservoir evaluation:A case study on Upper Wuerhe reservoir in the M1 well block, Junggar Basin

The sandy-conglomerate reservoir of upper Wuerhe formation in the M1 well block of Mahu Sag shows strong heterogeneity with pore structure and oil testing productivity. The sedimentary facies, diagenetic facies, fracture facies and reservoir comprehensive classification of upper Urho formation in M1 well block are studied by using core, thin section, logging and oil testing data. The results show that there are mainly two types of fan delta glutenite reservoir: gravity flow and traction flow, which correspond to three sedimentary microfacies such as fan channel, underwater distributary channel and debris flows. Four diagenetic facies, such as weakly-compacted facies and corrosion facies can be identified. Sedimentary facies and diagenetic facies are the main reservoir influence factors. According to this, the reservoir can be divided into 6 kinds of petrophysical facies. On the basis of sedimentary facies and diagenesis relative to the reservoir, the influence of the 6 types of petrophysical facies summarized as three types of reservoir, among which the reservoirs of type I and II are the best, the reservoirs of type III are the worst. Good matching of rock physical phase and oil test results in this area can effectively predict favorable reservoir distribution area.