Determination And Control Factors Of Oil-water Contact In Oil-water Transitional Zone Of Sanan Oilfield

Oil-water contact is the basis for calculating reserves and determining the oil boundary. Controlling factors of oil-water contact can predict the distribution of oil-water contact and provide an important basis for the oil well drilling, enlarging boundary, and taping potentials. Determination of oil-water contact and research of controlling factors of oil-water contact are very important and significant for the oilfield exploration and development.The paper determines oil-water contact using geochemic logging data, logging data and so on, researches the structural characteristics, lithology characteristics, physical property characteristics of research area, of which effects on oil-water contact.Two methods are used to determine the oil-water contact.First, with the help of production test data, to study characteristics of rock pyrolysis, pyrolysis gas chromatography, and fluorescence microscopic images and to analyze their response for oil and water beds.According to vertical combinationrelation of oil and water, oil-water contact of a single well is determinated.Secondly, the paper researches response characteristics of logging data for reservoir parameters, combining with production test data and core analysis data.Accodrding the relationship between the value of the log and reservoir parameters,and interpretation modes are built for identifying oil and water beds. Oil-water contact of a single well is determinated according vertical combinationrelation of oil and water beds. At last, oil-water contact of research area is detetmined.The effect of structural characteristics on oil-water contact can not be ignored. Using three-dimensional seismic data in the research area,the paperstudy its structural characteristics, and analyzes the effect of structural characteristics on the distribution of oil-water contact. Structural characteristics mianly affect oil-water contact from three aspect: first, structure controls oil and water distribution and high reservoir in the western oil transition zone is more conducive to accumulate hydrocarbon according structural location,which is one of reasons that western oil-water contact is higher than eastern oil-water contact. Second, structure control oil-water contact, so that variation tendency of oil-water contact is consistent with the structure. Third,faults do not form effective seal, so oil-water contact is consistent on both sides of the fault.Based on distribution of sand and characteristics of physical properties in research area, the paper analyzes the effect of lithology and physical properties on oil-water contact. Because of differences between lithology and physical properties, oil-water contact is higher in northern area of research area and oil-water contact in western transitional zone is higher than that in eastern transitional zone.