Development And Application Of Concentric Fishing Gas Lift Tools

With the development of gas reservoir, the formation pressure is gradually reduced, and the gas lift process parameters need to be adjusted periodically to adapt to the change of gas well.The conventional gas lift exchanges gas lift valves must implement the operation through pulling tubing string, is not conducive to the timely adjustment of parameters of gas lift, and high construction cost and long working cycle, easy to cause the damage of killing fluids formation; because gas is generally deep underground in Sichuan, complex conditions existing, eccentric retrievable gas lift exchanges gas lift valves of low success rate. Therefore, to develop a retrievable gas lift technology for Sichuan gas field is an urgent problem.Based on the above problems, this paper has carried out the research on the concentric retrievable gas lift, and achieved the following results:(1) Creatively put forward the idea of concentric retrievable gas lift:concentric mandrel and gas lift valve seat channel using concentric structure design, gas lift valve in the valve pocket after the steel wire operation for fishing. When the gas lift is carried out, the injection of high pressure gas by the work on both sides of the single flow valve to enter, open the gas lift valve and the liquid mixture, and then through the work of the gas flow channels in the cylinder to lift the mixed liquid. Compared with the eccentric retrievable gas lift, the concentric retrievable gas lift simplifies the operation of exchanging gas lift valve, which improves the reliability of the operation.(2) Completed the tool structure design. The valve pocket is used as X shape selective anchoring function of the lock core, to ensure its through and anchoring reliability; concentric mandrel and the gas lift valve are seated concentric tube channel, both sides are symmetrically provided with two single flow valve.In the concentric mandrel, there are 12 pores which diameter is 18mm and used to flow the gas and water, the total cross-section areas are 3053.6 square mm.(3) The key components of the tool are simulated and analyzed by using Solidworks2013 software. The results show that the tool structure design is reasonable. When exchanging gas lift valve, even by the 20kN on the pull, the most vulnerable to the safety factor of the valve capsule is also up to 6.57; in the condition of acidification is large displacement and high pressure pump, Even if the suspension of 3000m tubing, the concentric mandrel can still satisfygas lift-acidification pipe column combination condition.(4) To carry out middle tests include indoor gas lift valve exchanging experiment, concentric mandrel sealing pressure test, gas lift valve simulation well retrievable test,etc.The results showed that concentric retrievable gas lift exchanging gas lift valve has the advantages of simple operation, valve pocket and the concentric mandrel has a reliable sealing feature, gas lift unloading tool to normal. All performances of the toolachieve design requirement.(5)The tool has been applied in 7 wells, and has achieved good results. The field application shows that the performance of the concentric retrievable gas lift is stable, the operation is reliable, and the operation of gas lift valve is simple and easy to operate.(6) In the middle tests and field application tools in the form of exchanging gas lift valve construction technology, the company set up the enterprise standard--"Exchanging gas lift valve operation procedures for concentric retrievable gas lift", regulate the gas lift valve tripping operation, laying the foundation for concentric investment to further promote the application of exchanging gas lift valve.