Spray Cooling Schemes and Temperature Field Analysis of Ultra-High-Temperature Production Wells in Underground Coal Gasification

In underground coal gasification (UCG), it is essential for UCG production to accurately control the temperature of gas produced at wellhead well and correctly calculate variation law field in whole wellbore. wellbore structures use three sprayed water cooling schemes. These schemes consider heat exchange mechanism between formation, division into spray chamber section non-spray section, established model The research shows that, due large gradient formed transfer route under tubing injection scheme, drops most. annular scheme can protect cement sheath a certain extent easier implement; therefore, more suitable this cool well. It feasible by controlling chamber. greater daily output or thermal conductivity tubing, smaller change bottom hole wellhead, rises.