A Study on Bottom Water Coning Control Technology in a Thin Reservoir

摘要

The conventional method to control bottom water coning by perforating and setting a packer is not suitable for a thin oil reservoir, because it is hard to determine the perforation interval and place the packer accurately; thus, a novel technology has been proposed and developed in this article that can build up a gel packer in a thin reservoir by gravity segregation. The working fluids including high-density brine, selective blocking agent, and overplacing fluid were studied to form a gel packer, which is caused by gravity segregation resulting from density differences among oil, water, and working fluids in the water-oil transition zone and is used to control bottom water coning. The progress and the mechanism of control of bottom water coning using the novel technology by visual physical simulation experiments is also shown. By December 2008, this technology had been successfully applied in 38 wells of Luliang oilfield; the accumulated oil increment was 20,2201, the accumulated water decrement was 72,880 m~3, the water cut declined from 11.3 to 38.4%, and the input-output ratio was up to 1:2.41. The success of field tests confirmed that this technology is quite suitable for controlling bottom water coning in a thin reservoir and has a broad application prospect.