Research On Combined Development Technology Of Super Heavy Oil Steam Assisted Gravity Drainage And Steam Flood

The recovery ratio of super heavy oil conventional cyclic steam stimulation was low. In order to explore heavy oil development mode transform, and further improve oil reservoir recovery ratio, carried out SAGD pilot test on Du84 block of Shuyi district in September 2006. But part of wells didn’t reach the development plan design target from beginning to end, the key performance was low oil production, low oil steam ratio, low producing reserves and frequent steam break through between injector and producer.Through the oil reservoir research combined with dynamic analysis, the following two factors affected the SAGD development performance: First, interlayer developed partially in the XingⅥ group SAGD pilot test area, result in difficulty of the steam overlay and producing reserves above the interlayer. Second, the recovery percentage was low around the perforation zone of injector before SAGD, the extension of steam chamber was difficult, a steam chamber wasn’t formed, drainage channel was narrow, and the steam broke through easily.In order to improve the production performance of SAGD pilot test area, on the base of extensive research, detailed study and profound argument, innovated the combined development model of steam assisted gravity drainage and steam flood. The definition of the combined development model is that the gravity drainage is given priority between the steam vertical injection well and horizontal production well and the steam flood is given priority between the steam vertical injection well and vertical production well in the same area and layer which is named the compound drive. The purpose is to develop the reserves above the interlayer. Innovated to adjust the injector from continuous steam injection to intermittent rotation steam injection, its aim is controlling the steam break through, promoting the development of steam chamber and forming the stabilized oil drainage well.Two tests were carried out: First, respectively perforated and injected steam above and below the interlayer of the injectors in the interlayer zone. In the meanwhile optimized the vertical wells to produce in the edge area, formed the steam flood development with the injectors, and developed the edge reserves. Second, adopted rotation steam injection, promoted the steam chamber developing and controlled the steam break through against the high pressure of steam chamber among the injectors which broke through to the horizontal producers.This technology was carried out in the pilot test area on XingⅥ group of Du84 block, effectively developed the reserves above the interlayer in the pilot test area of XingⅥ group, greatly improved the production performance, entirely reached the plan design target, and achieved better economic benefits.