Development and Application of 56 Drainage Type Soluble Choke
In order to solve the problem that the downhole choke cannot be fished due to corrosion and locking of the locking mechanism,aging and deformation of the rubber barrel and severe liquid loading above the choke,a 56 drainage type soluble choke was developed.In the choke,the coated magnalium was used to make the lower seat of the slip,the water-soluble rubber was used to make the water-soluble rubber barrel,and a drainage struc-ture was added.In this way,the problems of corrosion and locking of the locking mechanism and difficult unsetting of rubber barrel can be effectively solved by injecting a solution to dissolve the lower seat of the slip and water to dissolve the rubber barrel;moreover,the problem of liquid loading above the choke can be solved by opening the drainage sliding sleeve to discharge liquid.The laboratory test shows that the corrosion resistance rate of the soluble lower seat of the slip in the stock solution is 0.053 6 mm/a,and the dissolution rate in 20%concentration hydro-chloric acid is 2 296.38 mm/a;the dissolution rate of water-soluble rubber in the 56℃stock solution is 2 370.73 mm/a;and the drainage rate of the drainage mechanism is 833 cm3/s.The field application in 8 wells such as Well Tao X shows that the temperature resistance,pressure resistance,corrosion resistance,sealing and unsetting performance of the developed 56 drainage type soluble choke meet the design requirements.During construction,it can smoothly complete the drainage and acid injection work;meanwhile,the dissolution and unsetting effect is good,and the success rate of fishing is 100%.This choke is suitable for ø73.0 mm tubing in horizontal and direc-tional wells.The developed technology and product provide strong technical support for the subsequent large-scale application at well site and serialization of the product.
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