Experimental Study On Flow Pattern Of Bubble In Horizontal Gas Wells

The technology of foam drainage gas recovery is applied extensively in drainage gas recovery of gas fields because of its low cost, rapidly effecting, easy to operate, wide application and no affecting to normal production of gas wells. At the same time foam drainage also plays a roll of steading yield in the horizontal wells of density and low permeability gas reservoir. But looked from the overall effect of horizontal foam drainage success rate is very low. One of the main reason is the understanding of bubble row horizontal gas-liquid two phase flow law is not clear, and the calculations of critical bubble carrying flow and pressure drop are not accurate, so leading to the choice of well conditions is not reasonable enough. Hence foam agent concentration and dosage are not reasonable. This paper have carried out bubble experimental and theoretical studies on multiphase flow around the horizontal well, the main work is as follows:(1) according to the structure characteristics of horizontal well, designed and set up horizontal well bubble multiphase flow simulation experiment device. The vertical section of device is4m high, horizontal segment is6m long, tilt section is10m long, outside the tubing combined with casing. This founded physical simulation experimental conditions for the study of the paper.(2) the paper tested pressure drop of the XHY-2, XHY-4, XHY-6three foam agent under different gas flow rate at the same concentration, from the view of dynamic performance optimizing XHY-4to be the best foam agent. Using high speed camera to observe bubble type multiphase flow at the different concentrations, testing the pressure drop under different concentrations and volatility, to a certain extent, the mechanism of bubble row agent concentration influencing the effect of drainage is revealed.(3) the experiment tested the influence law of fluid flow in horizontal wells for bubble multiphase flow, simulating the tubing entering to the top of deflecting section,the central region of deflecting section, the bottom of deflecting section and the middle part of horizontal section, obtaining the drainage ability of these four cases, providing the basis for the optimization of the displaying depth of horizontal well tubing.(4) testing the critical carrying bubble velocity at foam agent concentration of0-0.5%, inclined tube angle at27°-72°, the law of the reagent concentration influencing on horizontal well critical carrying bubble velocity is revealed.(5) based on the critical carrying liquid velocity of flowing in the vertical tube without foam agent and liquid continuous fitting, introducing the angle correction, the critical carrying bubble velocity calculation method of horizontal well is established, and using the tested data and field production data to verify the method, obtaining the accuracy of88.2%.(6) using the pressure data correction coefficient of friction, setting up foam multiphase flow pressure drop no-slippage model, and using the flowing pressure of horizontal well test data of the Daniudi foam drainage DP35-1to verify the model, the absolute error is0.17MPa.Through the experimental and theoretical study above, a theoretical basis for production dynamic analysis and the technology parameters optimization of horizontal well foam drainage is provided.