Simulation Experiment Of Velocity Pipe And Foam Composite Drainage Gas Recovery In Horizontal Gas Well

With the continuous production of natural gas,the energy and productivity of gas wells in kalameili gas field decrease obviously.Some gas wells show that the size of the production pipe column is large and the gas well has a serious fluid accumulation.In the early stage,the bubbling test was carried out.The effect was not obvious.Combined with the adjustment of the gas field development plan,we considered the discharge pipe in the original production string.From the experience of liquid drainage in vertical wells,velocity pipes can not solve long term liquid drainage problems in gas wells.Usually,velocity pipes should be combined with other technologies.The process of velocity tube drainage can reduce the slipping loss of gas and liquid effectively,reduce the critical liquid flow velocity of the wellbore and improve the liquid carrying capacity of the gas well.The bubble discharge process is mixed with the bottom of the well,and forms a foam under the agitation of the air flow,reduces the liquid density and the surface tension of the gas and liquid,thus bringing the well fluid out of the wellhead..Therefore,this paper is going to combine speed tube and foam drainage and gas recovery measures to carry out the simulation experiment of speed pipe and bubble discharge composite process.The main work is as follows:(1)in order to carry out the simulation experiment of the horizontal gas well velocity tube and foam drainage gas recovery process,a physical simulation experiment device of the visual horizontal gas well is set up.The horizontal section is long 8.27m,the vertical section is high 6.5m,the curvature radius of the elbow section is 0.64,1.27,and 2.55m respectively.The pipe diameter is considered 40mm,50mm,60mm.Pressure gauges are installed in horizontal section,elbow section and vertical section respectively,and the pressure difference between elbow and vertical pipe is mainly tested.It provides data support for the experiment.(2)the horizontal well experiment device has been built to carry out the contrast experiment of air water and foam flow pressure drop.The difference of foam flow and air water under different flow patterns was analyzed by measuring the pressure difference between different flow,liquid flow,pipe and vertical tube section under the flow pattern.(3)replace the two phase flow experiment by replacing the curvature radius of 0.64,1.27,2.55m with the horizontal well device built.Repeat the above experiments after completing a set of tube diameters and replacing the inner diameter 40,50 and 60mm diameter plexiglass tubes.(4)test the pressure drop of elbow and vertical pipe under different gas flow and liquid flow under different radius of curvature.By collecting the related data to study the rheological property of the foam,the pressure drop model of foam flow suitable for different radius of curvature is fitted,and the DXHW182 well is used to calculate the relationship between the foam quality and the flow velocity and the wellbore,the friction pressure drop and the gravity pressure drop.(5)test the flow rate of critical bubbling gas under the influence of radius of curvature under different diameter and concentration.The experimental data are tested to verify the existing formula of the critical foam gas velocity,and the coefficient of the theoretical critical foam velocity formula is corrected by the regression method combined with the influence of the radius of curvature.Thus the critical foam flow velocity model for horizontal gas wells with different deviating degrees is established.Taking DXHW172 well as an example,the production of pipe diameter 62mm oil pipe can meet the fixed output of 8 ×104m3/d,and the measures of foam drainage and gas production should be taken when the gas production is less than 5.8 × 104m3/d in the middle and late production,and a set of process plan is given.