Study On Logging Interpretation And Evaluation Method For Dense Carbonate Reservoirs In Da'an Village, Northeast

Tight oil and gas reservoirs are highlights and also one of difficulties in global unconventional oil and gas exploration nowadays.The Daanzhai reservoirs in Northeastern part of Sichuan contain porous and fare-porous reservoirs, which have the characteristics of complex lithological characters, complex pore structures, various of resveroir spaces and strong anisotropy, meanwhile thin layers and thin interbeds which they have makes them different from other common domestic tight reservoirs.These characteristics lead to weak well logging regularity and make calculating reservoir parameters more difficult and harder to evaluate reservoir effectiveness.Therefore we need to study further and establish a set of logging identifying and evaluation methods of that district, so as to serve reservoir exploration and development better.This ariticle analyzes thin layers’influences to logging response characteristics by numerical modeling, and discusses and analyzes the methods of thin layer logging response correction, consequently confirms the correction methods combining deconvolution method with frequency matching method.On the basis of geological understanding, The research of lithology, physical property, electrical property, hydrocarbon potential properties and their mutual relations indicate that the main lithology of Daanzhai reservoirs are shell limestone and shaly shell limestone, with poor physical proprety, and the development of fractures can improve permeability effectively.Conventional logging combining imaging logging and ECS logging to estabilish lithology recognition mode.Using a variety of methods to identify fractures and reservoirs and categorize porous and frac-porous reservoirs.Using gamma ray curve and deep resistivity curve which are sensitive to lithology to calculate the limestone and sandstone content, and then adopting mixed mineral matrix to calculate matrix porosity.Adopting dividing units of flowing to evaluate the permeability models in cored intervals, which improves the accuracy of models.By using empirical approach, minimum pore throat radius method, pore structure classification and pore-permeability relation method, we get the physical property lower limit.Using Multiple Linear Regression to evaluate fractures and get a good effect of actual use.The completion of this paper provides a complete, feasible method in the aspects of lithology recognition, reservoir recognition, calculating reservoir parameters and reservoir logging effectiveness evaluation in Daanzhai tight reservoirs in Northeastern part of Sichuan.