Development And Performance Evaluation Of Horizontal Well Water Blocking In Luliang Oilfield

Based on the research of resevoir geological features and development status in Luliang oilfiled, we studied the shutoff system and performance evaluation for horizontal wells, in order to plugging high permeability layers, protecting low permeability layer, reducing the moisture content of oil wells and realizing the oilfield production stability. We screened out the temporary blocking agent and primary blocking agent system by laboratory experiments and conducted a series of performance evaluation experiments and core flow tests. We also studied the construction technology of plugging horizontal wells and design the construction program for LUHW1327well and LUHW1225well.(1) The temporary blocking agent system for Luliang oilfield horizontal wells was screened:polymer HPAM2500mg/L+crosslinking agent A1600mg/L+crosslinking agent B1.0%(volume fraction)+gel breaker1800mg/L, which strength is H class, gelling time is9h, breaking time is3d. The primary blocking agent system for Luliang oilfield horizontal wells was screened:NQ38%+curing agent500mg/L+modifier1500mg/L, which initial curing time is50h, final cure time is95h and has high curing strength.(2) The temporary blocking agent and primary blocking agent system both have good temperature resistance, salt resistance, sheering resistance and injection performance. The primary blocking agent system also has the good performance:Water soluble0.06%, Oil soluble0.48%and Acid soluble1.3%, which viscosity is27.5mPa·s at46℃,(3) After core flow experiment of the temporary blocking agent and primary blocking agent system, we know that the plugging rate and the permeability recovery rate of the temporary blocking agent are above95%and80%for different permeability cores, the breakthrough pressure gradient and the plugging rate after10PV waterflood of the primary blocking agent system are37.6MPa/m and98.5%. The plugging rate of the system is above85%for high permeability layer and below20%for low permeability layer.(4) Studied the mechanism of the temporary blocking agent gelling and breaking and the mechanism of the primary blocking agent curing.(5) According to different sites of water breakthrough in horizontal wells and different features of agent systems, three types of water shutoff technique were studied:bottom hole pressure balance method, general injection method and temporary water shutoff method. We also design the construction plan of LUHW1327well and LUHW1225well.