Study Method On Computing Reservoir Parameters Using Well Log Data In Dongying Group Of A Region

The paper introduces the geological background of the A oilfield firstly, including the area location, stratigraphic lithological characteristics and logging material. Then preprocess the logging data, including logging environment correction, normalization and curve reconstruction, after that establishing the reservoir parameter model and calculating the reservoir parameters, including shale content, porosity, permeability and oil saturation. Next choose the correct method to predict shear wave, combining with p-wave and density to calculate petrophysical elastic parameters, analyzing the lithlolgy and fluid sentivity. Last, draw the plan of the reservoir parameters (effective thickness, porosity, permeability and oil saturation) to determine the location of favorable exploration in the area for studying. The paper’s specific content are as follow:1. Logging data preprocessingThe work of preprocess log data includes logging curve environment correction, standardization and well curves reconstruction. Logging curve environment correction is to eliminate the hole diameter, mud density and salinity non-geological factors; logging curves standardized is to eliminate the time, equipment calibration and human operation factor; and what the logging curve reconstruction is make use of multiple curves which can reflect the changes of reservoir characteristics to fit one curve that can not reflects the changes.The logging curve correction results are as follows:the reaming hole sections are mainly occur in the mudstone section, after flaring correcting, acoustic decreases, density increases, nature gamma increases, neutron porosity decreases, fitting the geological law. The result of log curves standardized illustrates the correction of AC, GR and R4are much larger, so it is all necessary to standard them, unifying all the wells in the region. After reconstructing, the value of acoustic, density and neutron porosity can reflect the changes of the reservoir characteristics.2. The interpretation model of reservoir parameters SP curve can calculate the clay content, which is in great agreement with the core sheet data; Establish the porosity and permeability interpretation model with core analysis of physical (porosity, permeability, density, ect) and well logging data (acoustic, density, ect). According to the pore type of A region, select the Archie model to calculate water saturation. Then establish the crossplots (R4and AC, porosity and Rt/Ro, R4and oil saturation) to identify the nature of fluid, the statistical results shows that the accuracy rate is more than80%.3. The analysis of logging petrophysical parametersIn this paper, I select Castagna menthod and Xu-White model to calculate formation shear wave, which compares the measured shear velocity, what the Castagna method calculates are in great agreement with the measured shear wave, but Xu-White model calculates the shear wave are error. S-wave, P-wave and density calculate petrpphysical elastic parameters, analyzing the lithlolgy and fluid sentivity, the results shows that the vertical and horizontal velocity ratio, shear modulus are the most sensitive parameter which reflects the character of lithology and fluid.4. The distribution of logging reservoir parametersIn this paper, I select tested wells as key wells, and according to the comparison analysis of the key well test intervals logging parameters and geological material, choosing Dongying formation, draw the plan of the reservoir parameters (effective thickness, porosity, permeability and oil saturation). The plans shows reservoir properties in northwest are much better than other area, and the oil saturation is generally greater than50%in northwest and east-central region, which are determined as the favorable exploration areas.