The Remaining Oil And Anisotropy Features After Flooding Control Of Mongolia Lin Sandstone Reservoir

Mongolia Lin oilfield structural feature is mildern bosslike anticline and faultsdevelopment.The core average porosity is22.4%; average Permeability is344.8×10-3μm2, the reservoir is mesothyridid poroustype reservoir.The original oil/water above sealevel150m, pressure gradient is0.73MPa, reservoir pressure coefficient is0.972,thereservoir is edge water weak elastic driven and low saturation layer reservoirThecumulative production of water flooding in Mongolia Lin sandstone reservoir is258.14×10~4t, degree of reserve recovery is20.29%.And weak gel treatmentcumulative production47.46×10~4t，degree of reserve recovery is22.12%，recoverypercentage just add1.83%afterprofile control and displacement.So Mongolian Lin sandstonereservoir still remain lots of crude oil after the weak gel adjustable flooding to improveoil recovery.Because the weak gel system and the water of flooding have largedifferences in fluid property, have an effect on plane and longitudinal reservoir’ssweep efficiency and caused the distribution of oil and water complex, the remainingoil greatly different from water flooding, therefore in this research project.This paper established3d structure sandstone reservoir model and the propertyparameter model on the basis of fine description in Mongolia Lin sandstone reservoir,and modify the geological model.The model have252mesh in X direction,have190mesh in Y direction, and have12layer in Z direction, in total of287280effective gridnodes.The model geological reserves is1453.9×10~4t, Compare With1381.34×10~4t ofactual geological reserves, fitting error of4.99%.However, modulate porosity,permeability, relative permeability curve, the original fluid saturation,viscosity-concentration curve of weak gel system, residual resistance factor and themaximum adsorption to achieve water flooding and weak gel flooding historical fittingcombined with the actual reservoir geological situation and the development tendencyof parameters.Among them is fitting well120mouth, the total85.7%of simulationpattern140mouth.In longitudinal direction,the numerical simulation results thatoriginal geological reserve in T1ys1oil group is502.11×10~4t, remaining402.56×10~4tafter water flooding,and remaining371.88×10~4t after weak gel flooding.So floodingcontrol increas the amount of oil30.43×10~4t, recovery degree increased by6.06%.Alsoresults that original geological reserve in T1ys2oil group is951.79×10~4t, remaining 758.6×10~4t after water flooding,and remaining714.47×10~4t after weak gel flooding.So flooding control increas the amount of oil44.95×10~4t, recovery degree increased by4.72%.But because the group T1ys1oil geological reserves is much lower than theT1ys2oil group, so the main reservoir is T1ys2.In plane,the numerical simulationresults the remaining oil relative enrichment in the small fault block. Such as: the northof22-16well area located in small fault, its energy short supply.Because injected wateraffected by gravity, Internal local Microstructure form the rich residual oil zone, such asthe remaining oil relatively enrichment in16-113northwest near area, located in theshape of the structure of anticline on top.Well pattern not control parts, such as: by5-12southeast area near, near the conglomerate layer.