The Research Of Injection-production Processing Technology For Improving The Vertical Producing Degree Of Steam Flooding And Its Application

The steam flooding technology is an important alternative technology used to transform development mode and improve oil recovery in Liaohe Oilfield. The technology has achieved industrial production and application in many blocks of Liaohe Oilfield. However, with the long time of application and the expansion of application scope, heterogeneous longitudinal exploitation of oil layers have existed which seriously affect oil production. In earlier stage the eccentric injection technology has been developed to improve the exploitation degree of oil reservoir longitudinally. During the process of eccentric injection, running and pulling tool is applied to convert the position of eccentric steam distributing valve and thus change steam distribution in different producing layers. The steam injection effectiveness has been affected due to low successful rate of running and pulling and difficult dynamic regulation of steam injector because of problems such as deformation of steam injection string and scaling existed in the eccentric steam distribution cylinder after long period of steam injection into down-hole string. Meanwhile, at present general commingled mode has been used for steam flooding producers, and the oil well production capacity has been reduced seriously due to inter-well interference phenomenon of oil producer in oil layers longitudinally because of the imbalance of inherent pressure of oil reservoir.Based on the previous study and combined with the present development condition and characteristics of steam flooding, the concentric double layers injection technology has been researched to optimize string structure. At the same time, the calculation model used to calculate well-bore pressure, temperature, dryness fraction, well-bore heat loss for concentric double string steam injector has been established and steam injection parameters are designed optimally. Field applications have showed that the technology can meet the requirements of complementary injection quantity for oil reservoir, and dynamic regulation of steam injection quantity for upper and lower formations can be achieved in the wellhead. From 2012 to 2014, the technology has been applied for 19 wells in Liaohe Oilfield with 100% operational successful rate and efficiency rate and the accumulated oil increment is 4.9×104(tons), which showed a good application effect. Meanwhile, the separated layer oil production technology for steam flooding has been investigated according to the characteristics of steam drive producer and tested both in laboratory and oil field. The pump inspection period of test well is 373 days, which is 44 days longer than commingled production pump period. The accumulated incremental liquid production is 2787.2 m3, and the accumulated oil increment is 662.5 (tons), which gained good results from field test. The longitudinal utilization degree and development efficiency of steam drive block are improved greatly through improvement and perfection of injection and production technologies.