Study On The Well Logging Evaluation Methods For Reservoirs Of Ordovician In Ordos Basin

With the constant improvement of the degree and level of exploration and developmentof oil and gas field, and the expansion of the exploration area, carbonate reservoir of LowerPaleozoic in Ordos Basin has become an important exploration object, and an importantresearch goal for oil and gas industrial circles. But as a result of carbonate reservoir with thecharacteristics of complex lithology and fracture pore structure, fracture open degree andfracture density is difficult to determine, strong anisotropy and heterogeneity, low porosity,low permeability, changeable formation water salinity, and difficult to identify fluidproperties, it brought multiplicity of solutions, vagueness and uncertainty to loggingevaluation. The problems need to attack are carbonate reservoir identification and reservoirevaluation.On the basis of core analysis, logging data, logging information, test gas data, and so on,in Tabamiao area, combined with the geological background, lithologic features, physicalproperties and pore structure characteristics of the reservoir are investigated and determinedin this thesis. Combined with reservoir space type of this area, a variety of well loggingmethods for identifying carbonate rock fractured reservoir and logging responsecharacteristics is investigated. Using existing spectrum logging and conventional logginginformation, the sensitivity of fracture, pore and cave reservoir is analyzed, the ratiocharacteristic parameters of reservoir is investigated, the quantitative computation of reservoirparameters is made and logging reservoir evaluation is conducted. According to thecharacteristics of the open hole logging series, logging series suitable for carbonate evaluationis selected, and effect analysis is conducted.According to the above research thought, a set of well logging evaluation methods whichare suitable for carbonate reservoir in Tabamiao area are established. The following resultsand understanding are obtained:1. A variety of logging methods for identifying carbonate fractured reservoir and loggingresponse characteristics is investigated;2.From the conventional logging data and spectrum logging data,8characteristicparameters of reservoir rapid classification are constructed, the technology of intersection, overlapping, and comprehensive comparative analysis of combination parameters is used, andit provides a practical method for reservoir identification;3.Using the core data, the reservoir parameters such as porosity, permeability,saturation are studied systematically, calculation model for reservoir parameters such asporosity, permeability and saturation of carbonate reservoir in Tabamiao area are established;On the basis of water analysis data, rock electricity experiment data, the correspondingprocessing parameters are analyzed, and value taking method and scope are determined;4.According to the specific situation in Tabamiao area, the characteristics of open holeseries are analyzed, the suitable logging series for carbonate reservoir evaluation in this area isdetermined;5.Application effect analysis of carbonate logging series for the five wells in theresearch areas is conducted, logging reservoir evaluation is done again for the five wells.From the perspective of logging data interpretation and geological application, theproject research makes full use of various logging information, the carbonate reservoir isevaluated, a set of well logging evaluation methods suitable for carbonate reservoir inTabamiao area are built up, therefore, the research result has extremely high spreading value.