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Study On The Effective Medium Esistivity Model For Reservoir With Low Porosity And Permeability In Shaly Sands

Posted on:2010-04-13Degree:MasterType:Thesis
Country:ChinaCandidate:P XieFull Text:PDF
GTID:2120360278957957Subject:Earth Exploration and Information Technology
Abstract/Summary:PDF Full Text Request
Evaluation on low porous and permeable reservoirs is a difficult problem for logging interpretation. Since Daqing FuYang shaly sand reservoirs with low porosity and permeability are characterized by including clay bound water, capillary bound water and free water, and forming three different conductive networks, and the conductance mechanism of clay bound water is different from that of capillary bound water or free water, the conducting mechanism for the kind of low porous and permeable shaly sand reservoirs can not be described with a simple parallel conductive theory or Archie's formula. Herein, a effective medium three-water conductive model for low porous and permeable shaly sand has been proposed, based on experimental measurements on low porous and permeable shaly sand samples, concept of three water, symmetrical anisotropic effective medium theory, and geneses and conductance mechanisms of low porous and permeable reservoirs. By analyzing effects of some factors on the proposed model, we find some rules. Shale distribution largely affects water saturation predicted by the model. Resistivity index decreases and formation conductivity increases as fraction and conductivity of laminated shale, or fraction and conductivity of clay bound water, or conductivity of sand grains increases. Resistivity index increases and formation conductivity decreases as fraction of capillary bound water increases. Resistivity index increases and formation conductivity decreases as percolation exponent of clay bound water or percolation exponent of capillary bound water or percolation rate of sand grain increases. Resistivity index decreases and formation conductivity increases as percolation rate of capillary bound water, or percolation exponent of sand grain increases. We employ sample experimental datas from low resistivity reservoirs to validate the proposed model, then to solve the model for water saturation and parameters.On the basis of that the program is compiled to interpret the logging data. Validation with experimental measurements of rock samples and interpretation results for log data shows that the proposed model can improve the accuracy of the evaluation for Daqing FuYang shaly sand reservoirs with low porosity and permeability, and meet the needs of exploration and development for Daqing oil field.
Keywords/Search Tags:low porous and permeable reservoir, capillary bound water, clay bound water, free water, symmetrical anisotropic effective medium conductance theory, effective medium resistivity model
PDF Full Text Request
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