| Shale gas is an unconventional natural gas that has been extensively exploited globally in recent years.In the exploitation of shale gas,due to the use of bridge plug fracturing technology,bridge plug debris is unavoidably generated in the horizontal wellbore,affecting logging equipment and other follow-up equipment downhole.In order to meet the cleaning and salvaging requirements for bridge plug debris in wellbore,this paper carried out research work on a horizontal wellbore cleaning and salvage tool based on the principle of negative pressure,and focused on breaking through the overall scheme research,structural research and performance research and simulation of cleaning and salvaging tools.This paper compares the horizontal wellbore impurity cleaning and salvage schemes at home and abroad,and combines the two major technical requirements of impurity salvaging efficiency and tool reliability,and proposes the overall technical scheme of shale gas horizontal wellbore cleaning and salvaging tools based on the negative pressure principle.Based on the principle of negative pressure,the overall structure of the entire cleaning and salvaging tool was studied,including four key parts: safety protection device,negative pressure generating device,impurity storage device,salvage device.The tool is used to clean and salvage impurities in the wellbore based on the principle of negative pressure.The negative pressure is the decisive factor affecting the efficiency of the entire tool cleaning and salvage.To improve the efficiency of the tool cleaning salvage,the core structure jet pump of the negative pressure generating device is first theoretically studied and affected.Jet pumps generate negative pressure and key energy loss in the flow path,including: ground pump supply flow,nozzle outlet diameter,throat diameter.Then use ANSYS Workbench’s CFX module to simulate the runner flow field in the inner flow channel of the jet pump,and obtain the influence of“negative pressure”in the horizontal wellbore cleaning and salvaging tools with different inlet conditions and structural parameters.Finally,the tool’s salvage efficiency is obtained through MATLAB simulation.The relationship between the magnitude of negative pressure,optimization of each parameter through simulation results to obtain a set of optimal downhole parameters,asmuch as possible to reduce the energy loss within the tool under the premise of ensuring the salvage efficiency of the tool.The horizontal wellbore cleaning and salvage tool studied in this paper is applied to wells with depths of 3,000 to 4,000 meters,and the horizontal wellbore casing diameter is only 120 mm.To ensure that the designed horizontal wellbore cleaning and fishing tools can work safely and reliably downhole,use ANSYS.Workbench’s statics module performs reliability analysis on cleaning and salvaging tools to verify the design rationality of the tool. |
