Unloading using auger tool and foam and experimental identification of liquid loading of low rate natural gas wells

摘要

Low-pressure, low-producing natural gas wells commonly encounter liquid loadingduring production. Because of the decline in the reservoir pressure and the flowcapacity, wells can fall below terminal velocity. Identifying and predicting the onsetof liquid loading allows the operators to plan and prepare for combating the liquidloading hence saving valuable reserves and downtime. The present industrialapplications of artificial lift, wellhead pressure reduction by compressor installationat the wellheads and reduction in tubing size are costly and often intermittent. Thethesis examines the above aspects to generate a workflow for identifying andpredicting the liquid loading conclusively and also assessing the application ofAuger Tool and foam combination towards achieving a cost effective and moreefficient solution for liquid unloading.In chapters I-IV, I describe the process of using production surveillance software ofHalliburton Digital Consulting Services, named DSS (Dynamic SurveillanceSoftware), to create a workflow of identifying the liquid loaded wells based on welldata on daily basis for field personnel and engineers. This workflow also decides the most cost effective solution to handle it. Moreover, it can perform declineanalysis to predict the conditions of liquid loading.In chapters V-VIII of the thesis, I describe the effort of handling the problem ofliquid loading in a cost effective manner by introduction of an inexpensive AugerTool in the bottomhole assembly and using WhiteMax surfactant soapstick fromJ&J Solutions. Four different combinations of well completion and fluid were testedfor performance in respect to liquid hold up, pressure loss in the tubing, unloadingefficiency and critical flow requirement. The test facilities and instruments, alongwith the operational methods, are discussed in chapter VI.Except for the reduction of the operational envelope with the inclusion of AugerTool, the performance improved with the insertion of Auger Tool. The bestcombination of Auger and foam system could be a result of flow modification by theAuger Tool caused by reduced pressure loss and increase in drag coefficient andalso by reduced density and surface tension of foam.