Research On Optimization Of Gel Profile Control System And Injection Parameters In Low Permeability Reservoirs

Low permeability reservoirs generally have the characteristics of strong reservoir heterogeneity,complex pore structure,poor reservoir physical properties,etc.The physical parameters and production dynamic characteristics of different blocks are also quite different.In recent years,with the development of water injection,the water content of the produced liquid in low permeability reservoir is on the rise,and the effect of water injection adjustment is slow and the difficulty of oil stabilization and water control is increasing.For reservoirs with strong heterogeneity,there are obvious water flow channels after long-term water flooding,and the inefficient and ineffective circulation of water flooding becomes more and more serious,so the oil displacement effect is not as good as before.It is necessary to take profile control measures in order to improve the efficiency of water flooding in low permeability reservoirs and alleviate the contradiction between horizontal and vertical heterogeneity of reservoirs.By effectively blocking the high seepage channel,the low permeability unworked reservoir is affected,and the overall reservoir utilization is expanded.In the horizontal well area of low permeability reservoir blocks A and G in the past two years,a series of profile control measures have been taken to solve the problem of poor water injection development effect,which has improved the development effect to some extent.However,due to the short duration of profile control measures,poor reservoir physical properties and small oil tolerance,the conventional profile control technology still has many inadaptability,and the profile control effect of different blocks is still uneven.Therefore,in this paper,A G block horizontal wellblock early after profile control injection pressure is high,the water absorption capacity,short the period of validity and horizontal well water breakthrough of technical problems,based on target block geological characteristics,specific profile control measures were taken,design a set of experimental screening test is suitable for low permeability reservoir of gel profile control system method,and carried out a series of gel system of injection parameter optimization indoor experiment,specific work is as follows:?1?using heometer to 48 kinds of formula test blocks in different gelling time under the condition of gel strength,viscosity?gel?,gel strength,stability,elastic parameters?stress relaxation?and the blocking rate,scouring resistance,breakthrough pressure gradient.Through the laboratory evaluation experiment,the best formula of profile control agent suitable for the heterogeneity of horizontal Wells in block A and G was optimized.?2?by carrying out 4 laboratory evaluation experiments on profile control radius,displacement radius,corresponding plugging radius and injection speed,a series of optimization was carried out on profile control agent injection parameters,so as to improve the effective period of plugging and the water-absorbing capacity of Wells after profile control,and finally improve the development effect of horizontal fracturing Wells and improve the recovery rate.After a lot of indoor experiment and the formula of comprehensive contrast,ultimately selected the best prescription of A block is:0.7%polymer P₂+1.21%crosslinker J₂+0.01%C+0.15%W,G block the best formula is:0.7%polymer P₂+1.34%crosslinker J₂ promoters in C+0.01%C+0.15%W,the formula meet the practical requirement of A and G oilfield wellblock horizontal well.According to the injection parameter optimization experiment on sanguan parallel core,the optimal profile control radius of the horizontal well area in blocks A and G is above 6m,the displacement radius is 3-6m,the corresponding plugging radius is about 50%of the seam length,and the injection speed is 0.06-0.24m³/?MPa/m/h?.At this time,the indoor ultimate recovery rate is the highest,so it is the optimal scheme.Based on the geological characteristics of blocks A and G in low-permeability reservoirs,this paper carried out a series of laboratory experiments on the optimization of the gel system and the optimization of injection parameters.The gel system suitable for the research block was optimized and the corresponding injection parameter design results have improved the remaining oil utilization ratio in the study block and achieved certain results.The research results of this paper have important value and significance for the optimization of profile control system for low permeability reservoirs and future field construction.