Research And Application On The Heavy Oil Flow Mode

The heavy oil reservoir is special oil and gas reservoir and has many differenceswith conventional reservoir. Because of high oil viscosity and being very difficult tobe developed， its main development method is steam injection.The study of heavyoil flow mode is key to develop the heavy oil reservoirs scientifically. The research ofthis paper is based on heavy oil reservoirs in Shengli oil field. The heavy oil flowmode was studed by experiment method and theoretical researching and guidescientific development of heavy oil reservoirs.Based on experiment results， the heavy oil flow mechanism， distributioncharacteristics of flow field, heavy oil flow mathematics model and flow mode bythermal were studied and established in this paper. The following main achievementsare made by this research.1. By experiment method the rheology characteristics and effect factors andmechanism on oil viscosity were investigated. The relationship between oil viscosityand limitation temperature which transfer non-newtonian to newtonian flow wereestablished.2. Based on lab data，the rules and characteristics of heavy oil flow were studied.The opinion that heavy oil flow is nondarcy flow with threshold pressure gradient wasproposed. The effect factors of threshold pressure gradient were analyzed. Thethreshold pressure gradient formula and flow motion mathematics equation andflow equation with threshold pressure gradient were established， which candescribe the heavy oil flow characteristics.3. By experiment method，the characteristics of relative curve with oil and waterphases was researched and fractional flow curve description method wereinvestigated.4. The different region flow mathematics model of areal well pattern by verticalwell steam injection in homogeneous and heterogeneous heavy oil reservoirs wasestablished. The solution of flow mathematics model by semi-analytical method wasstudied.5. The software to calculate heavy oil flow by semi-analytical methods wasdeveloped，which can calculate flow mode， distribution of temperature，pressure andoil saturation with areal well pattern in different cycles by vertical well steam injection and different regions of heavy oil reservoirs include conventional，super andextra super heavy oil.6. Based on results of distributions of temperature，pressure and oil saturation andcombined with test data in situ，the thermal flow mode of heavy oil reservoirs wasestablished.7. The achievements of the paper were used in Shengli oil field，Such asdeterminating limit drainage radius of conventional production with reasonable welldistance，interpreting reason of high water cut in low oil saturation heavy oilreservoirs and using thermal method to improve production performance.