Research On Damage Mechanism And Protection Measures Of Steam Injection In Heavy Oil Reservoir

The heavy oil is usually used for steam injection,because the heavy oil is characterized by heavy,high viscosity,poor flow,strong temperature sensitive and so on.Although the steam can promote the development of heavy oil effectively,the high temperature,strong alkali vapor injection will bring damage to the formation,such as:clay expansion,mineral and rock skeleton dissolved,clay mineral conversion,crude oil composition changes and so on.In this paper,Haqian 22 reservoir in X oil field is taken as the research object,and the goal of the paper is to study the protection of reservoir technology in steam injection.Based on the study of the geological characteristics and damage mechanism of the loose sandstone reservoirs and the test result of haqian 22 reservoir,the reservoir protection technology in the steam injection of Haqian 22 reservoir is studied in this paper.Through the application of the appropriate anti-high temperature clay stabilizer,optimizing the steam injection process and other measures to carry out steam injection reservoir protection technology,it provides important basis for steam injection in oil field.Based on the previous research,this paper has carried on the thorough research on the sensitivity change of the steam injection process,the clay mineral transformation,the mineral dissolution and the change of the crude oil component,and has determined the mechanism of steam injection damage in 22 loose sandstone sand.The injection of high temperature,strong alkali vapor,will enhance the damage of alkali sensitivity,temperature sensitivity and so on;it will promote the expansion of clay mineral;it can promote the conversion among clay minerals,promote the formation of water-sensitive clay minerals;it causes the dissolution of minerals,resulting in sand or even collapse and other damage;can cause changes in crude oil components,asphaltene components increased,after the blockage of channel,seriously affecting the effective development of reservoirs.According to the damage caused by steam injection,chlorine-free small cationic clay stabilizer,clay stabilizer NW,clay stabilizer NW-6,clay stabilizer S-403,Xinjiang A chemical plant production of clay stabilizer No.1,No.2,No.3 seven kinds of clay stabilizers were screened.Chlorine-free small cationic a clay stabilizer and clay stabilizer S-403 are screened out through comparing the compatibility of anti swelling,water washing and other properties of the seven clay stabilizers.According to the mechanism of steam injection damage in haqian 22 shallow sandstone reservoirs,the protection measures such as optimizing steam injection rate and controlling steam pH are put forward.