Research On Heavy Oil Gas Lift Assisted With Light Oil Injected From The Annulus

Heavy oil resources are abundant in China,but most of the heavy oil reservoirs are difficult to exploit,and the cost is high,which seriously restricts their exploitation.On the basis of a large number of domestic and foreign literature research,the coupling model of wellbore pressure and temperature is established on the basis of the mechanism of wellbore flow and the research object of thick oil well.In order to preliminarily observe the mixing process of heavy oil and thin oil,the accuracy of the pressure drop model of the wellbore is verified,and the simulation experiment of thick oil mixed gas lift is carried out.The experimental tube column with high 5.7m was set up in the experiment,the diameter of the casing was 80mm,the diameter of the tubing was 30mm,the pressure sensor was installed at the bottom and the top of the casing,and the pressure sensor was installed at the top of the tubing.Then the data measured in the experiment are compared with the calculated data to verify the accuracy of the model.The sensitivity analysis and the optimization of the process parameters are carried out with the actual field well as an example.The main work of this article is as follows:(1)taking the thick oil well as the research object,the wellbore is divided into three sections.The pressure drop of the fluid in the annular air is calculated by the Mukherjee&Brill model,and the pressure drop in the oil pipe is calculated in two sections.The viscosity and gas to liquid ratio of the heavy oil are changed by the addition of the dilute point below the dilute point,which has changed the viscosity of the heavy oil and the gas to liquid ratio.Based on that,a suitable pressure drop calculation model is found out,and a coupled model of heavy oil and lean gas lift shaft pressure and temperature is established,and the model is solved.(2)taking the Visual Basic 6 programming language as a programming tool,based on the Hagedorn-Brown pressure calculation and Hasan-Kabir temperature calculation method and the annular Mukherjee&Brill pressure calculation method,the coupling calculation program of the pressure and temperature of the thick oil mixed gas lift wellbore is compiled to predict the pressure temperature of the well bore of the heavy oil mixed gas lift well.(3)to build a simulated experimental frame with a thick oil mixed gas lift,the experimental frame is 5.7m high,the diameter of the casing is 80mm and the diameter of the tubing is 30mm.The experimental data is recorded and the experimental data are observed.The experimental data are observed and the experimental data are compared with the program calculated data to show the reliability of the pressure drop model.(4)the influence of dilution on the temperature and pressure of the wellbore,the influence of gas injection on the wellbore temperature and pressure,the relation between the volume of the mixture and the quantity of gas injection under fixed output conditions,the relationship between the output of heavy oil and the quantity of gas injection,the relationship between the output of heavy oil and the quantity of the heavy oil,and the relationship between the yield of heavy oil and the quantity of dilute have been analyzed.The best amount of dilution and gas injection rate is obtained,and the distribution of wellbore pressure and temperature under the condition of dilute volume and gas injection volume is obtained.(5)field example application analysis,in order to verify the feasibility of the mixed gas lift technology in the thick oil well and the effect on the heavy oil production,the field test is carried out.The formation of crude oil is almost solid state at normal temperature,and the well has been produced by dilution production before the experiment is carried out.Two tests were carried out in the field,the first was the YQX well in Tahe oil field,Xinjiang,which injected the dilute oil and nitrogen into the annular space simultaneously;the second test was in well TK677,and the dilute oil and natural gas were injected into the air from the annular space.The feasibility and effect of dilute gas lift are analyzed by analyzing the experimental data.Combining theory research,indoor experiment and field test,this paper studies the technology of dilute gas lift,which provides guidance for the exploitation of heavy oil...