Comprehensive Evaluation Research Of Polymer Microsphere Deep Profile Control In Low Permeability Or Tight Reservoir

At present,applicability of polymer microsphere deep profile control technology in low permeability and tight reservoir is not yet clear.Microsphere application effect depends on the key technology such as degree of recognizing reservoir characteristic and agent selection.Effect evaluation methods of polymer microsphere deep profile control has not yet formed specification,and evaluation results obtained by different effect evaluation methods are different.Therefore,it is necessary to combine theory with practice to evaluate development effect and mechanism of microsphere pilot test area according to specific reservoir characteristic and microsphere characteristic.Comprehensive evaluation study of microsphere deep profile control was carried out for the PGL pilot test area.Firstly,carrying out the secondary well test interpretation to quantify plane heterogeneity of single well by using proprietary low mobility well test analysis software,and quantifying inter-well heterogeneity to realize re-recognition of reservoir heterogeneity characteristic by using inter-well water breakthrough channel analysis software.Secondly,according to the established comprehensive effect evaluation system of microsphere deep profile control,evaluating the effect from three levels: single well,well group and test area.Thirdly,analyzing main effect characteristics and seepage mechanism of microsphere by combining dynamic and static analysis.Finally,identifying main control factors of microsphere deep profile control,and selecting applicable theory evaluation models of microsphere deep profile control.Studies suggest that the PGL pilot test area was pure oil reservoir with relatively good physical property.Liquid producing capacity and injection capacity were relatively good.The time of low water cut production was relatively long.Crack-net of oil well near-well was mature.Seepage condition of water well near-well was abnormal.Water breakthrough channel of inter-well was relatively mature.Water breakthrough channel thickness and permeability contrast were relatively large.The reservoir heterogeneity was relatively strong.The main effect characteristic was that oil production was stable and water cut was reduced.Seepage mechanism was that microsphere blocked inter-well water breakthrough channel,and improved plane water flooding equilibrium,water injection utilization rate,sweep volume and oil recovery.The evaluation model for short term effect was recommended to correct model parameters to application according to reservoir geological characteristic and seepage mechanism.But effect simulation had poor predictability.In addition,the evaluation model for EOR can simulated and forecasted changes of production,water cut,oil recovery and so on.After microsphere implementation of first round,filed evaluation results showed that water cut fluctuated at 54%.well efficiency was 37%.Oil increment of per ton microsphere was 3.17 t.Therefore,microsphere deep profile control in PGL pilot test area reached expected effect of water cut reduction and oil stabilization.According to above studies,PGL pilot test provided engineering basis for application and popularization of microsphere deep profile control technology in low permeability and tight reservoir.The study on microsphere deep profile control comprehensive evaluation was beneficial to subsequent field study on selection of test area,layer and agent,and microsphere injection parameter matching decision.