Adjustable Steam Injection Process Design In SAGD Horizontal Well

During the development of SAGD, the key factor influcing production is development scale of horizontal steam chamber, namely, using length of horizontal section. The two key factors influencing using length of horizontal section are the reservoir’s heterogeneity and rationality of injection pipes, because the reservoir heterogeneity is very difficult to change, the point increasing production is to design a set of reasonable steam injection string according to the implementation of SAGD in heterogeneous reservoir and uniform steam injection is in the SAGD process so as to improve the yield of heterogeneous reservoir SAGD. Based on this, this paper carried out targeted research.The object of this paper was Du84block of SAGD development areas, it put forward to carrying out adjustable steam injection process design of horizontal well SAGD to realize the wellbore uniform steam injection and SAGD steam cavity uniform expansion, to improve the SAGD development effect and ultimate recovery, it got a set of well group uniform steam injection pipe string structure for Du84block SAGD development zone. Firstly, it studied the domestic and foreign various SAGD injection pipe string structures, summed up three column structures and their evolution, such as:the single tubing steam injection, parallel double pipe of steam injection, concentric dual tubing steam injection, and it got disadvantages of the pipe column structures; Then combined with the domestic actual development of SAGD dynamic test, the steam flow and distribution characteristics of different string structure are analyzed, under the condition of all kinds of pipe string structures, it got deeper understanding in steam distribution characteristics. Based on SAGD effect and the steam chamber distribution characteristics analysis under the conditions of various column structures, according to the mass conservation equation, energy conservation equation and momentum conservation equation, respectively, it got steam flow characteristics analytical equations of different oil drilling pipe combination, including single pipe,parallel dual tubing, concentric dual tubing. It was analytic characterization from the mechanism and technology of steam flow. Finally, research on adjustable steam injection process designs of horizontal well SAGD under different pipe structures.