Research On HP & HT Reservoir Sensitivity Of Western South China Sea Oilfield

The main object of my study is the Dongfang Gasfield of Western South CNOOC.The group of Huangliu reservoirs include a total of three Dongfang gas field areas, named Dongfang 1-1 well area, Dongfang 13-1&13-2 well area. The reservoir of Huangliu is a kind of abnormal high temperature and pressure group formation, the formation temperature reachs as high as 150 degrees Celsius on average, the average reservoir pressure 53MPa. Experiments, such as HP/HT sensitivity experiments and water block, Jamin are included in this article.The mechanism of formation damage can be divided into two aspects. One is the interaction between injected fluid and reservoir rock,which causes external solid particles invasion, the sensibility caused by incompatible injected fluid injectivility, the movement of internal particles,sanding,bacterial plugging and so on. The other is due to the imcompatibility between injected fluid and formation fluid,which causes emulsification, inorganic scale, organic scale,iron rust and corrosion product and formation solid deposition. These damaging factors always interact with each other, which can make the damage deteriorate. When taking reservoir protective measures, it is necessary to consider the interaction of all aspects.In the process of oilfield development technology growing in many geological experts. In the course of practice and gradually realize that oil and gas recovery factor is not limited to the impact of reservoir space and temporal distribution of genetic types, the occurrence of the development process reservoir Sensitivity field decline also contributed to the damage, recovery suffered a major root cause of the bottleneck.Reservoir Sensitivity refers to the degree of difficulty and the late development of oil and gas drilling process of reservoir damage (ie, the degree of sensitivity). Reservoir Sensitivity damage may occur at any time or space to develop oil and gas reservoirs, and water from the well to a series of measures are likely to cause damage to the reservoir sensitivity occur, so the sensitivity of reservoir damage prevention is a long and arduous task. Carried out in the early development of oil and gas reservoirs in time-sensitive research can provide an important basis for the formulation of drilling mud, oil and gas exploitation rate, water program design, and can prevent the occurrence of "mistaken" in the follow-up exploration operations, the sensitivity of reservoir protection oil and gas fields of work is long-term and stable mining an important cornerstone.In the study of reservoir protection under high temperature and pressure test environment, researchers have conducted a succession of high temperature high pressure fluid filtration, high pressure and temperature working fluid performance optimization and other aspects of research, and the sensitivity of reservoir simulation study of high temperature and pressure formation environment also very little difference between reservoir sensitivity for high temperature and pressure and temperature and pressure conditions do not have a precise understanding of the need for pioneering experimental research in this area, the need for high temperature and pressure sensitivity experiments clear.Experimental study of high temperature and pressure by the sensitivity of the Eastern Gas Reservoirs Mitsui core area, and found the East 13-1 wellblock sensitive to damage to the main water sensitivity and Jamin, other less sensitive damage. Oriental 13-2&1-1 wellblock well each sensitive area damage have occurred, especially in the speed-sensitive, water-sensitive, acid-sensitive and Jamin damage strongest.The speed-sensitive damage of 13-1 well area is weak, higher critical velocity for 48.95m/d; water sensitive degree weak-weak moderate, critical salinity is 4648mg/ L; alkali sensitivity, acid sensitivity and stress-sensitive damage weak, non-critical pH, well area only DF 13-1-4 well 9MPa measured value of the critical stress, single well the extent of damage than other wells in medium weak stress-sensitive damage.Dongfang 1-1 wellblock’s speed-sensitivity damage is weak, but the critical velocity is very low, only 1.49m/d; high water sensitivity extent of the damage, but less critical salinity of 4648mg/L; alkali sensitivity to moderate the extent of damage weak, the critical pH value 8.5; acid sensitivity rate of 62% damage, the extent of damage and strong middle; stress-sensitive damage weak, critical stress value 9MPa.Oriental 13-2 overall damage well area is the strongest blocks, speed-sensitive, water-sensitive and acid-sensitive general extent of the damage to the middle strong-strong, and has a low critical velocity characteristics, is 1.45m/d, critical mineralization large differences in the degree of each well, including the Oriental 13-2-2 well critical salinity 4648mg/L, the highest critical salinity Eastern 13-2-8d Well, the same is 13944mg/L, and formation water salinity; alkali sensitivity extent of the damage and Eastern District 1-1 well balanced, critical pH value lower,7; stress-sensitive damage is weak, the critical stress value 15MPa.Oriental contrast with HP/HT gas temperature and pressure sensitivity results, found no effect on the extent of high temperature and pressure sensitive and water-sensitive base damage, but the speed-sensitive and acid-sensitive damage had some impact. HP/HT wells speed Oriental 13-2 damage sensitive areas is significantly higher than normal temperature and pressure, the DF 13-21-1 wellblock well region under simulated temperature and pressure conditions of formation of acid-sensitive damage is significantly higher than normal temperature pressure condition one to two levels.Dongfang 1-1 overall well area and strong sensitivity to the DF 13-2 well area is the main cause of its relatively high content of clay minerals, kaolinite, Eamonn mixed layer has a large area, such as the distribution of chlorite, pyrite and there Mining and mineral composition of amorphous silicon aggravated damage.Dongfang gas field as a whole is weak because of stress damage sensitive research sandstone detrital quartz content of up to 60% to 76% quartz content is dominated by quartz high strength, ability to resist deformation under loads, easy deformation.