Compound Stimulation Techniques for Heavy Oil Reservoirs with Bottom Water

In the Zhuangxi Oilfield, horizontal wells in heavy oil reservoirs with strong bottom water are characterized by high liquid production, high water cut, poor development output and difficulty in producing the remaining. In order to solve these problems, a series of studies was carried out to develop compound stimulation techniques for heavy oil reservoirs with bottom water. First, the mechanisms of carbon dioxide huff and puff for improving oil recovery of horizontal wells with bottom-water were analyzed through visualization experiments. Secondly, a viscosity increasing foam system was prepared by optimizing foaming agent and foam stabilizer so as to deal with carbon dioxide flooding fingering. And thirdly emulsified asphalt blocking agent was prepared by optimizing emulsifier so as to blocking high-permeability paths. The compound stimulation techniques were designed based on carbon dioxide huff and puff, viscosity increasing foam system and the development of an emulsified asphalt blocking agent. These techniques were applied seven times in heavy oil reservoirs containing bottom water of Block Zhuang 1. The techniques resulted in a remarkable increase in oil production with a corresponding decrease in water production,, with average water cut reduction 27.5% and cumulative oil incremental 3 205 tons. Based on field application, these compound stimulation techniques application in horizontal wells of heavy oil reservoirs containing bottom water could decrease water content and solve the difficulties of producing remaining oil.