Research On The Remaining Oil Distribution Characteristics Of Low Permeability Reservoir During Medium-high Water Cut Period

In this paper, WangYao District of AnSai oilfield is the main research object. It revealed the distribution and change pattern of remaining oil in low permeable reservoir from the macro, micro, ground plane and profile angle, then discussed the formation and distribution mechanism of remaining oil controlled by all kinds of geological and developmental factors and finally established an integrated description method for studying and extracting the potential of low permeability reservoirs'remaining oil during medium-high water cut period.Through the research the following aspects of creative work are accomplished: 1.Integration of oil reservoir engineering, numerical simulation forecast, remaining oil real-time monitoring and dynamic analysis of remaining oil comprehensive evaluation enhances the remaining oil prediction accuracy; 2.Application of Lorenz curve method in fine depiction of low permeability reservoir water flooding profile improves the way in studying the water drive degree purely with injection profile statistics; 3.Researched the microscopic remaining oil distribution characteristics of low permeability reservoir during medium-high water cut period and offered the direction of reservoir reformation in developing microscopic remaining oil; 4.Through pressure coring and indoor simulation experiment, reservoir variation characteristics of low permeability reservoir after long period of water flooding is analyzed, and difference reservoir changing mechanism after water injection development between low permeable and medium-high permeable reservoirs is discussed. The results show that the long-term development by water flooding reduced the reservoir permeability, enhanced the heterogeneity and lowered the physical property.This paper can provide the theoretical direction in choosing suitable injection-production system, deploying infill wells and choosing of oil and water Wells in reservoir reformation, which has an important practical significance in keeping high and stable production and EOR of Low permeability reservoir.