Generalized Electrical Efficiency And ABC And Clay-coating Grain Resistivity Model For Laminated And Dispersed Shaly Sands

Based on the electrical efficiency model for clean rocks and the double water model and parallel conductance between laminated shale and dispersed shaly sand, improved electrical efficiency resistivity model is proposed for laminated and dispersed sand shaly interpretation.This model shows that shale distribution largely affects total water saturation calculations. The curvatures of curves between total formation conductivity and total water saturation are affected by cation exchange concentration ,cemetation exponent m and coefficient a 0,b 0,saturation exponent n , and the effect increases as total water saturation increases, the effect of n on relationship between total formation conductivity and total water saturation decreases as total water saturation increases. Based on parallel conductance between laminated shale and dispersed shaly sand, and ABC resistivity model proposed by V.S.Afanasyev et al, a generalized ABC resistivity model is proposed for laminated and dispersed sand interpretation. This model shows that shale distribution largely affects total water saturation calculations. The curvatures of the curves between total formation conductivity and total water saturation are affected by cation exchange concentration, cementation exponent m and coefficientb , the effect increases as total water saturation increases. Based on parallel conductance between laminated shale and dispersed shaly sand, and clay coating grain resistivity model, a generalized clay coating gain conductivity model is proposed for laminated shale and dispersed sand interpretation.This model shows that shale distribution largely affects total water saturation calculations. The curvatures of curves between total formation conductivity and total water saturation are affected by grain rock resistivity,clay resistivity,m , and the effect of m increases as total water saturation increases, the effect of n isn't obvious. By studying the solution to generalized electrical efficiency resistivity model and generalized ABC resistivity model and generalized clay coating grain resistivity model in laminated and dispered shaly sand, it shows that there is local minimum of the functions about total water saturation derived from the models in range from 0 to 1.Therefore,in order to ensure the iteration convergence,we adopt a hybrid algorithm combining Newton and bisection,and the calculated result shows that using the hybrid algorithm to solve the equations about total water saturation is convergent. Rock sample data in dispersed shaly sands and well logging data in laminated shaly sands show that the proposed models may be applied not only in dispersed shaly sands but also in laminated shaly sands. Therefore,the proposed models can be considered as generalized resistivity models. By studying calculationof all parameters in three resistivity models, the effective methods are proposed.We interpret log data of SU#1 and SU#3 in very shaly formation of Hai La Er Basion with the three models and compare effect water saturation calculated with the models with oil-testing results.It shows that effect water saturation calculated with the models proposed in the paper are applied to very shaly sands.