Moliqing Oil Reservoir Of Strong Water Sensitive Reservoir Acid Defuse Plugging Technology Research

Against yitong Moliqing downfaulted basin in the shuangyang group second segment of the actual situation of reservoir water flooding difficulty first respectively for oilfield formation damage, well plugging, oil well corrosion reasons, potential acidification, harm and cause of fouling five factors such as re-recognition and analysis, the results show that besides formation sensitivity to damage, suspended solids, dirty, bacteria and corrosion products, potential secondary sediment acidification and asphaltene colloid also damage to the reservoir. Then analyzes the sandstone reservoir minerals with hydrochloric acid, hydrofluoric acid, fluosilicic acid and fluoboric acid and the reaction mechanism of acid such as hydrogen acid, provide theoretical support for optimizing acidizing. In comprehensive analysis Moliqing reservoir characteristics, reservoir damage mechanism and acid rock reaction mechanism on the basis of the system is put forward to carry out the water-in-oil type emulsified acid broken down and alcohol-based acidolysis plugging system research and remove formation damage evaluation, the early stage of the basic research for the field application.Using single factor method to screen emulsion retarded acid, broken down the main acid system formula:63% mud acid+30% 0# diesel oil+2% compound emulsifier +1% iron stabilizer +3% expansion agent +0.1% platoon aid.Development of liquid surface tension of emulsified acid broken down small, leading to the spreading coefficient in oil wet rock interface, is advantageous to the acid-rock reaction uniform; Viscosity than emulsion mud acid slightly larger, to increase the internal phase of the penetration resistance of H+, reduces the acid-rock reaction rate; Density than emulsion mud acid slightly smaller, be helpful for the residual acid fiowback. The emulsified acid has a slow, anti-corrosion, bentonite and damage of rock skeleton small excellent properties, such as dissolution rate rise slowly slow drop, is conducive to the acidification of the near wellbore area.Based acid main acid system formula:8% HCl+6% NH4F+1% ATPM+1% SL-HS2 (inhibitor)+1% EDTA stabilizer (iron)+2% expansion agent (KL inorganic salt+SL cationic surfactant)+0.1% FC7321 agent (help)+25% ethanol. Alcohol-based plugging fluid also have retarded acid solution, anti-corrosion, bentonite and damage of rock skeleton small excellent properties, such as dissolution rate of sandstone core of rise slowly slow down, and achieve the purpose of the slow dissolution, beneficial to deep strata broken down and remove pollution.Ndoor simulation acidizing technology field experiments showed that emulsifying retarded acid system broken down the acid and alcohol acid solution blocking system can effectively restore and improve the core permeability after not pollution and pollution, can meet the requirements of site construction.