Research On Profile Control Technology Of Polymer Flooding In GD Oilfield

Aiming at the problems of high concentration of polymer in oil wells and serious concentration of oil in the oil wells in the GD oilfield,a technique of profile control,flood prevention and synergy in the polymer flooding formation is proposed.By analyzing the on-site tracer data and the data of the polymer flooding stage in the water flooding stage,the necessity of the regulation and drive is determined.The difference between the water flooding and polymer flooding diversion rules of heterogeneous reservoirs was investigated by numerical simulation software.The experimental results show that the ability of polymer flooding to improve the flow rate is limited,and the profile control effect is not satisfactory.The existing jelly formula for GD oilfield The optimization design of the injection parameters of the jelly was carried out,and an index system suitable for the profile control of the polymer flooding reservoir was established.By adjusting the formulation of the jelly system,a profile control system with different gelation properties was constructed.In this paper,polymers J135,N162-1 and N162-2 used in GD oilfield are used as gelling as agents,and the gelation time,gelation strength,long-term stability and cost of the gel are used as evaluation indexes at 70 °C.A series of phenolic jelly formulations with different gelling properties have been developed.The formulation of the jelly system was optimized.The addition of nanoparticles greatly improved the long-term stability of the gel.The gelation time,gel strength and long-term stability were used as evaluation indexes,and the gelation time was optimized at 20 h.The rubber strength is in the H grade,and the 60-day water loss rate is about 2%.The optimized jelly formulation was evaluated for shear resistance evaluation.The pre-shearing test of the gelation solution showed that the nanoparticles could greatly increase the shear resistance of the jelly.The effects of the jelly system on the sealing performance of the formation were studied by means of various physical modes.The physical simulation experiment of the sandpack shows that the constructed jelly system has good long-term stability;considering the economic benefit and reservoir damage rate,the optimal dosage of the gel is about 0.3PV;the reservoir heterogeneity is an important factor affecting the sealing performance of the jelly,as the permeability is extremely poor,the sealing effect of the jelly is reduced.The flat panel simulation experiment shows that after the gelatin profile control,the oil saturation in the vicinity of the mainstream line decreases significantly,the sweeping area of the reservoir increases,and the cumulative recovery factor is improved.The microscopic visualization simulation shows that after the jelly profile control,the liquid flow steering ability of the polymer flooding is greatly increased.Considering the plugging performance and economic benefits,the final formula for determining the deep profile control of the GD oilfield polymer flooding reservoir is: 0.3% N162-2 + 0.04% medium molecular weight phenol + 0.04%Urotropine + 0.1% LS + 0.2% Thiourea + 0.2% SW-30.