Analyses Of Production Performance In An Oil Well Based On Oil-water Relative Permeability Curve

Oil and water relative permeability is the fundamental parameter in controlling fluid flow, and analyses of production performance in an oil field make an important part of the researches on reservoir engineering. Here, we took oil-water relative permeability curve as the breakthrough point to discuss the methods of production performance analyses in an oil field.Firstly, the calculative method of oil and water relative permeability is presented. Oil-water relative permeability curves of 31 cores are obtained by this method. According to the morphological characteristics of relative permeability curve, relative permeability curves of experimental cores are divided into three groups, specifically, water phase upconcavity type, water phase intermediate type and water phase concave down type. Then the injection-production relations of displaced core are deduced in this paper. The saturation distribution equation, the expressions of relations between PV number and water cut and the expressions of relations between PV number and displacement efficiency are also proposed here. The expressed features and development effects of different type of the relative permeability curves are analyzed on isoosmotic point, isoperm region and terminal point, etc. Production performance of oil wells can be studied directly by the morphological characteristics of relative permeability curves.Secondly, from oil-water relative permeability curve, association with oil-water fluid flow theory, in order to pursue assessment methods of regulations on the rate decline and effusion flux, relative permeability curve form method and single point predicted method are presented. During the application of relative permeability curve form method, based on measurement of oil-water relative permeability curves, decline types of production performance can be predicated from the form of curves if the controlled reservoir is estimated, and other related parameters can be calculated. So the rate decline analyses can also be used in new oil wells. On the other hand, if the controlled reservoir in unknown, the parameter of rate decline and the dynamic reservoir can be determined by extending the relative permeability curve form method to type curve matching method. While after water breakthrough, single point predicted method can be used. If production data at one time are given, data of next time can be predicted. So this method makes the rate decline and water performance prediction come true.At last, analyses on the calculated relative permeability curves and production data show that the relative permeability form method is available during the early stage of oil field development. While during the later stage of development only the single point predicted method is available. By integrating the two methods, the performance of oil wells in different stages can be predicted. In the paper, the detailed analyses on the rate decline type and water flooding characteristics of Sheng-132 well show that when analyzing oil wells production performance, segmental evaluation method is fairly effective.