Reservoir Technology And Application Of Jurassic Tri - Low Reservoir In The Northern Qaidam Basin

In recent years, with the North Qaidam in Qinghai oilfield exploration efforts increasing, in the fish card-mahai gaxun slope area, five number in cold lake, scan1well sag in madong slope of the dry lake basin in mabei uplift zone and other constructions the good oil and gas shows.In2010,on cold lake90wells,91wells, Su1exploration well, long1exploratory well and other exploratory wells were acidized and fractured. In2011,on long2wells two layers were conducted a fracturing test oil transformation, but due to the North Qaidam Jurassic reservoir with a "low permeability, low temperature, low flow back" feature, after the fracture the draining of the reservoir is poor, severely affected the oil test results, how to increase the flowback rate of these measures after the reservoir has become a bottleneck in the North Qaidam exploration.Through the North Qaidam Jurassic three lower reservoirs transform technology research, flowback after fracture research, thereby enhanced measures three low reservoir flowback rate and improve the effect of three low reservoir, resolved the North Qaidam Jurassic three low reservoir single measures liquid and craft issue and achieved three low reservoir exploration breakthrough, provided technical support for stable production and achieved the following conclusions.(1) North Qaidam Jurassic reservoir are mostly porosity reservoirs, effective natural fractures, low permeability, low flow back after the measures and likely to cause secondary damage.(2) Reservoir lithology is complex, strong sensitivities(most formations have water sensitivity), formation pressure is low, the conventional reservoir stimulation technology is difficult to implement, low measure effective rate, the effect measures is not ideal.(3) According to the construction site statistics show that North Qaidam three low reservoir measures is poor, the measures flow back rate is low.(4) Fracturing fluid system has low pertinence, conventional fracturing fluid is not suitable for three low reservoir measures.(5) Through the three low reservoir fracturing fluid system research, screening energized fracturing fluid system and related additives,formed energized fracturing process.(6) The stimulation technology which adapted to the characteristics of three low reservoirs in northern Qaidam block has been successfully applied completed15wells,reservoir reconstruction measures.