Research On Temporary Plugging Acidizing Technology In ChengDao Oilfield

The main oil reservoir of guantao formation in Cheng Dao oilfield is the main oil producing position at sea,but the oil production rate is low,hard to suit the requirements of high efficiency development,and not matched with the requirements of the high-speed economic development.How to further enhance oil recovery rate is the main problem facing development activities at sea;The main problem that restricts fluid extraction is the pollution of oil Wells and the low level of formation pressure.However,due to the high interlayer heterogeneity of guantao formation in Cheng Dao oilfield,Conventional acidification often causes very little acid to enter or fail to enter the low permeable layer,or is blocked and contaminated in the oil outlet channel during acidification.However,hypertonic layer,large pore or fracture are further acidified,leading to increased heterogeneity,which fails to achieve the purpose of relieving damage of medium and low permeability layers.Based on this,it is very necessary to carry out the study on the temporarily blocked acidification process of offshore oil fields,which can not only effectively block the high permeability layer,but also remove the pollution of the low permeability layer.This paper analyzes the composition of blockage in Cheng Dao offshore oilfield by means of experiment,summarizes the characteristics of the clog and explores the reason of forming blocking object,which provides a basis for the optimization of plugging solution formulation and the formulation of process plan;According to the characteristics of the reservoir,the suitable temporary plugging agent formula was selected.According to the blockage forming mechanism of Cheng Dao oilfield and the physical and chemical properties of the plugging material,the suitable plugging solution formulation was selected.The compatibility of plugging fluid and temporary plugging agent with formation fluid,formation rock particles and cementite is studied through chemical simulation and physical simulation,and select suitable auxiliaries;Adopting indoor physical model to investigate the temporary plugging agent in the formation of the porous medium sealing characteristics and permeability recovery,single acid system was studied in solution of formation plugging performance,and proved the overall purpose of temporary plugging acidizing technology on layer(low permeable formation)has good effect.Finally through the field application shows that temporary plugging acidizing technology in Cheng Dao crude oil has obtained the good effect,should further popularization and application.