Study On Formation Mechanisms And Rules On Poisonous Gas Mainly Including CO In Deflagration Fracture Process

At present, deflagration fracture of oil well has been very widely used to increase production and injection in low-permeability and ultralow-permeability reservoirs. Pollution and clogging which caused by drilling and perforating and various measures can be effectively eliminated near wellbore area. So the technology can improve the environment of infiltration fluid near wellbore area and attain the aim of increasing productivity of oil-gas wells and affusion of water well. However, with the technology being used widely in low permeability reservoirs, in recent years,several carbon monoxide(CO)intoxication accidents in such as Changqing ultra low permeable oil field occurred in deflagration fracture process. Some great economical losses and personnel hurts have been caused, which have been limiting the deflagration fracture technology to develop further more.Based on this, in this paper, the formation mechanisms and rules of poisonous gas mainly including carbon monoxide (CO) in deflagration fracture process were studied systematically in low-permeability and ultralow-permeability reservoirs. The study showed that poisonous gases for deflagration fracture were mostly carbon monoxide (CO) and hydrogen cyanide (HCN) and the primary reasons to produce toxic gas were that the bomb itself and that high energy gas for deflagration fracture reacted with associated gases and oil. And the formation-mechanism and countermeasures of poisonous gas were illuminated. The study is of great theoretical value for prevention poisonous gas in effect, and is of great guiding significance for the rational development of similar oilfields.