| The oil reservoir of Y1 176 block in Bonan Oilfield has a depth of 3500-4200m,an overlapped oil-bearing area of 51.5km2,and a proven reserve of 3038×104t.The research section is the Sha-3 Member and the Sha-4 Member.The reservoir is controlled by the structure and lithology.It is a typical low porosity and low permeability reservoir.Therefore,the micro-characteristics of the Yi 176 Block reservoir in Bonan Oilfield must be studied.The core of the study area was analyzed through microscopic lamellar identification,scanning electron microscopy,and so on,Then we can study the petrological characteristics of the detrital mineral components,detrital structural features,interstitial features,and lithologic features.Then through the constant rate mercury injection,high pressure mercury injection,environmental scanning electron microscopy,pressure hole percolation,and micro-nano-CT scan experiments to study the microscopic pore throat structure characteristics of the reservoir in the study area,determine the pore type,throat type and microfracture type,pore throat development,pore throat distribution,and microscopic connectivity of the throat.Based on the mercury porosimetry method for the study of microscopic pore throat structures and the identification methods for tight fractures in tight sandstone reservoirs,the tight sandstone reservoirs in the study area can be divided into four categories,six sub-categories,among them,the reservoir of the underwater distributary channel microfacies is the type of I reservoir,the reservoir of the estuary sand dam phase is the type of II reservoir,and the reservoir with a mat-like sand microfacies is the type of III and IV reservoir.At last,Combining physical data with the distribution characteristics of sediments to predict reservoir surface distribution.Among them,the development of type I reservoirs is relatively mature,and category II and III are the major exploration and development directions in the future. |
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