The Design And Research Of Multi-lateral Well Bridge Type Transition Joint In Tahe Oilfield

After long term exploitation,Tahe Oilfield is short of energy in the formation,and the initial oil layer becomes higher in water saturation.However,there are lots of oil in the interwell through survey.Sidetracking multi-lateral well costs lower than drilling new wells.What's more,the initial oil layer will be injected water to boost pressure and drive oil with the multi-lateral wells production,which improves productivity effectively.The wells in Tahe maturing field are smaller in diameter,can't contain two tubes,besides double tube injection-production is a complex process which is difficult to repair wells in later period.It is necessary to design a bridge type transition joint for 7? " and 7" casing string in order to separate two channels of water injection and oil extraction.Therefore,the purpose of single tube injection-production is achieved—— annulus water injection and central tube oil production.On that basis,strength checking and fluid-solid coupling should be carried out by FEM simulation for verifying the designed tool's security and feasibility,and the lower joint wall thickness was modified 0.5mm.Finally,the relationship between balanced offtake and outer radius of inner tube was studied by numerical simulation.Morever,the balanced offtake diagram under different pressures was drawn.It is of great significance to single tube injection-production in single well,laying a foundation for further improving the oil recovery efficiency in Tahe Oilfield.