Research On The Affecting Factors Of C₉Reservoir Characteristics And The Development Of Horizontal Well In Wucangbao Oil Region

The object of this assay is C9typical low porosity and permeability reservoir inWucangbao oil region. Using a mass of logging data, experiment data and geological data, wemade a detailed study on C9reservoir in this area. By systematically analyzing the reservoircharacteristics and the affecting factors of the development of horizontal wells in lowpermeability reservoir, we put forward the prospective blocks in the horizontal welldevelopment.The C9reservoir lithology of Wucangbao oil region is mainly for the light and dark grayfine grained lithic arkose, has low textural maturity and poor physical properties. Its averageporosity is8.0%and the average permeability is0.18×10-3μm2. It belongs to the typical lowporosity and permeability reservoir and has stronger heterogeneity. C9reservoir in this area islocated in the delta front facies. The distribution of the sand body is controlled by sedimentarymicrofacies. Thus, the underwater distributary channel sand body constitutes the main sandbody. In this area, reservoir C91-1and C91-2thin sand body develop and have a large scale ofdistribution. Reservoir thicknesses are always between5m and20m, oil and gas enrichment ismainly controlled by sedimentary microfacies, physical properties, nose-uplift structureconditions，the oil and gas enrichment area mainly gathered in underwater distributarychannel sand body and local nose-uplift area; therefore, it belongs to the structure andlithologic reservoir, So, this area not only possesses geological conditions of horizontal welldevelopment, moreover, it has a pretty prospect to develop.Combining with Wucangbao oil region horizontal well development present situation andthe geological affecting factors of low permeability reservoir horizontal well development, wefound out the factors that influence the development of C9reservoir horizontal well. The mainfactors are reservoir thickness, permeability, reservoir heterogeneity and fracturecharacteristics; the secondary factors are reservoir depth, fluid viscosity, interlayercharacteristics and reservoir sensitivity characteristics. We also provided screening standardsfor the various factors parameter requirements and applied effective basis for horizontal welldevelopment in future. According to C9reservoir characteristics and reservoir characteristicsresearch, we saw C91-1thin layer as major reservoir in Wucangbao oil region horizontal welldevelopment, selected the prospective wellblock, thus, we thought A and B wellblock in C91-1thin layer is suit to develop horizontal well.