Genesis Of Log-interpretation For Low Resistively Oil Reservoirs In DongPu Depression

It's very difficult to distinguish and evaluate for low resistively oil reservoirs, because of its especial electric property and irregular nature. Many experts home and abroad had been looking for better and more effective evaluate methods for a long time, trying hard to distinguish low resistively oil reservoirs from conventional oil reservoirs. At the same time, researching the calculational methods of parameter for low resistively oil reservoirs, in order to provide reliable reservoir parameter. Although there are some successful experience, geological characteristic and origin of oil pool are different, evaluate methods and technology are disaffinity.DongPu depression is a Cenozoic fault basin with high-salinity formation water, low-porosity, low permeability, fine lithology and small fault block. Different characteristic low resistively oil reservoirs had been discovered in different tectonic zone during exploration and development. They are an important component of reserves, making a contribution to output of Zhongyuan oilfield. There are 3 difficult problems to distinguish and evaluate for low resistively oil reservoirs due to their particularity:â‘ Its genesis and distribution rule are not quite clear,â‘¡Logging methods are defective,â‘¢Computation modules for reservoir parameter of low resistively oil reservoirs are imperfect.Through analyzing the character of low resistively oil reservoirs in DongPu Depression,further studies on origin of low resistively oil reservoirs.Make the best of well-logging information,together with the data of testing for oil or producing test,Developing the study of effect of mud distributional forms and contents on log response,confirm the relation between different mud distributional forms and contents and log response.Established log interpretation model which fit for low resistively oil reservoirs of high natural gamma-ray. The result of practical application indicated It is very effective that the methods of oil-water relative permeability and combination lithology to interprete low resistively oil reservoirs .