Design And Study On Drainage Gas Recovery Through CT Velocity String

With the large-scale gas production,the number of low-yielding wells will be more and more.In recent years,due to the good economic efficiency,simple operation and good drainage gas recovery effect,drainage gas recovery through velocity string has been widely using in each big gas fields in our country.But the drainage gas recovery through velocity string system currently used there are unable to work under pressure,prone to sand plugging problems.Aiming at these problems,this article first for the overall design of the drainage gas recovery through velocity string system,and then select Li Min model as a vertical gas well with critical fluid flow calculation model,Select Hagedorn-Brown model as CT velocity string inside the pressure drop calculation model.Providing a theoretical basis for the engineering application of reasonable diameter optimization.It also investigated the downhole tool string and the main supporting tools for structural design,the main tool to establish a working theory,and using ANSYS finite element analysis software structural optimization for key parts of hydraulic release type fisher and coiled tubing operations joints.After calculated critical with liquid flow rate of different diameter,different bottom hole flowing pressure and different depth and wellhead pressure different diameters,different gas production and different water production by Li Min and Hagedorn-Brown model.Finally using matlab software to write the critical carrying fluid flow,erosion flow and pressure loss procedures programs,and through simple examples illustrate how to use the software for a reasonable preferred diameter.In this paper,using ANSYS finite element analysis software to optimize the structure for the dogs of hydraulic release type fisher and coiled tubing operations joints and get rational design parameters.Got the relationship between gas well depth,flowing bottomhole pressure,coiled tubing diameter and critical carrying liquid by calculation through Li Min model.Got the relationship between water production,gas production,coiled tubing diameter and wellhead pressure by calculation through the Hagedorn-Brown model.Using the set of CT velocity string drainage gas recovery system device,can be achieved with pressure job and sand blocking purposes;using critical with fluid flow,erosion flow and pressure loss software,can facilitate optimal tubing.