鄂尔多斯盆地庆阳气田山1段储集层特征及控制因素

Reservoir Characteristics and Controlling Factors of Shan 1 Member in Qingyang Gas Field,Ordos Basin

鄂尔多斯盆地庆阳气田属于典型的致密砂岩气田,主力气层为二叠系山西组山1段,砂体厚度薄且变化快,储集层分布预测难度大,制约气田的产能建设。通过井震结合开展沉积砂体刻画和薄储集层预测,探讨储集层发育的主控因素,明确有利储集层分布区。结果表明:古地貌与古流向共同控制三角洲砂体的分布,溶蚀相发育的水下分流河道砂体为最有利的储集体,局部微幅度鼻隆构造为天然气富集区。综合砂体展布规律、储集层物性、成岩作用、构造特征等因素,建立了研究区储集层分类标准,在研究区南部和中部识别出2个Ⅰ类储集层富集区。

In the Qingyang gas field,Ordos basin,which is a typical tight sandstone gas field,the major pay zone is the first member of the Permian Shanxi formation.Its sedimentary sand bodies change rapidly with small thickness,making the prediction of reservoir distribution difficult,which restricts the productivity construction of the gas field.In this paper,sedimentary sand body characterization and thin layer prediction were carried out using loggingseismic combination,the main factors controlling reservoir development were discussed,and favorable reservoir distribution areas were identified.The results show that the paleogeomorphology and paleoflow direction jointly controlled the distribution of delta sand bodies,the underwater distributary channel sand bodies with developed dissolution facies are the most favorable reservoirs,and the local microamplitude nose uplift structure is the natural gas enrichment area.Based on the factors such as sand body distribution,reservoir physical properties,diagenesis and structural characteristics,a set of standards for classifying reservoirs in the study area was established,by which two Type I reservoir enrichment areas were defined in the southern and central parts of the study area.