米脂气田盒8段优势储层研究及钻井有利区域评价

Dominant reservoir research and favorable drilling zone evaluation of He-8 Member in Mizhi Gasfield

长庆油田米脂气田盒8段气藏地质储量789.8×10^(8) m^(3),采出程度不到1%,是具有上产潜力的重要区块。虽然储层单砂体厚度较大,但由于储层物性较差,有效气层厚度较薄,富气储层展布规律不清,钻探效果较差。为加快米脂地区产能建设,必须精细化地质认识和潜力评价,寻找有利区带,优选井位布钻。通过细分小层沉积微相研究,精细刻画各小层含气砂体的展布特征;通过储层岩心微观特征研究,利用聚类分析法制定了储层分类标准,在沉积微相控制的基础上,落实了优势储层的展布特征;采用多层优势储层叠合方法优选有利钻探区带;在合理开发对策指导下,进行井位优选,取得了较好的钻探效果。

The gas reservoir of He-8 Member in Mizhi Gasfield of Changqing Oilfield has OOIP of 789.8×10^(8) m^(3) and its degree of reserve recovery is less than 1%,so it is an important block with the potential of productivity construction.Its single sand body is thicker,but its reservoir physical properties are poorer,the effective gas layers are thinner and the distribution laws of gas-rich reservoirs are not figured out,so the drilling effects are poorer.In order to speed up the productivity construction in Mizhi area,it is necessary to refine geological understanding and potential evaluation,search for favorable zones and optimize well locations.The distribution characteristics of gas bearing sand bodies in each sublayer are depicted precisely by analyzing the sedimentary microfacies of each sublayer.Then,the reservoir classification standard was formulated by means of the clustering analysis method by studying the microscopic characteristics of reservoir cores.On the basis of sedimentary microfacies control,the distribution characteristics of dominant reservoirs were clarified.Afterwards,the favorable drilling zones were selected by means of the multi-layer dominant reservoir superimposition method.Finally,well location optimization was carried out under the guidance of reasonable development countermeasures.As a result,better drilling effects are achieved.