Study Of Technology And Key Equipment Design Of Snubbing Based On Minor Overhaul Workover Operation

This thesis is combined with the National Science and Technology Project " Demonstration Project of Coalbed Methane,Tight Gas and Shale Gas Co-production in Coal-bearing Strata of Linxing-Shenfu Area "(NO.2016ZX05066004-002).Based on the analysis of the drainage characteristics of coalbed methane and tight gas,this thesis summarized the problems of coal mine methane and tight gas after the existing conventional minor overhaul operations,such as capacity decline and reservoir damage,and the necessity of conducting snubbing operations was proposed.At the same time,aiming at the existing problems of the existing oil and gas field pressurized working equipment applied to the tight gas wells of coalbed methane,a compact gas-tight gas operation process based on minor overhaul operations was proposed,and a snubbing operation equipment based on minor overhaul operations was designed.The key systems and equipment were designed in detail,and the physical prototype of the snubbing minor overhaul equipment was developed.Relevant experiments were carried out and the operation results were evaluated.Firstly,the development status of pressure workover equipment in oil and gas fields at home and abroad and the status quo of minor overhaul workover operation of coalbed methane and tight gas wells were introduced.The reasons why existing pressure workover equipment cannot be directly used for minor overhaul of coalbed methane and tight gas wells were analyzed and summarized.The tight gas repair work should meet the requirements of nonempty,snubbing,and fast operation.Corresponding to the design requirements of the snubbing operation equipment based on minor overhaul work.According to the design requirements,the scheme of the snubbing equipment based on minor overhaul work was designed,and its working principle was introduced in detail.The snubbing equipment was divided into a sealed blowout prevention system,a forced lifting system and an auxiliary equipment.At the same time,combined with the operation equipment,the snubbing operation technology based on minor overhaul work was proposed to realize fast and minor overhaul work.The sealed blowout prevention system was then designed,including a wellhead seal blowout prevention system and a plugging tool inside the tubing.The gas-controlled annular blowout preventer was designed to realize the smooth passage of the tubing coupling through the gas concession.The finite element analysis of the sealing performance and failure of the rubber core of the annular blowout preventer was carried out,the results meet the sealing requirements;The design of the tubular pump plugging saves the time spent in the original process to salvage the tubing plug.The forced lifting system was designed.The critical length of the tubing that is used to switch the hook and the forced trip is determined by the force balance point in the lifting work.In order to meet the requirements of height and stability,a double-acting two-stage lifting hydraulic cylinder was designed,and the parameters such as maximum downforce and flow rate were determined.The strength analysis and stability analysis were carried out,and the results proved that the operation requirements were met.Select the universal kava to achieve the anti-top protection of the tubing while reducing the overall height of the device.In order to improve the snubbing operation equipment,the auxiliary equipment such as the connecting frame and supporting tools were designed and selected.Finally,the physical prototype of the snubbing operation equipment based on the minor overhaul operation was developed.The annular blowout preventer pressure sealing test and lifting test were carried out.The operation results of the snubbing operation equipment were evaluated in combination with the test data.The results show that the snubbing operation equipment meets the pressure requirements and can be completed in an ideal time.Through the research and experiment in this thesis,the snubbing operation equipment based on minor overhaul operation can complete the quick minor overhaul operation without crushing the well and not venting,reducing the reservoir damage and capacity reduction caused by the long working time.At present,it is of great significance to damage the reservoir by tight gas repair work of CBM and improve the operation efficiency.