Commissioning Advanced Hoist Technologies to Mitigate Challenges Associated with Selective Workover Wells - A Revolutionary Approach

Abstract

Since 2014, ADNOC Onshore has utilized the potential of hoists and commissioned its operational significance, which allowed saving in rig time (4 – 6 rig years per year over 5 years business plan period) and generating a cost saving opportunity. During this period we have faced many challenges and complications mainly during fishing operations which result in unsuccessful retrieval of the completion. Other factors and challenges that are commonly faced which require hoist intervention include: Old wells melted or corroded fish (Tubing + Casing)Reservoir Thammama Zone B wells (High water cut)Pushing the corroded fishComplete plug & abandonPartial plug & abandon required for future side trackWait on conventional rig arrival for intervention Main challenge we faced during our business development phase is losing number of oil producing wells due to fishing complications, therefore the hoist rig is not capable to drill or sidetrack such wells. This will result in delaying requirements to restore production and meet the field quota objective since the wells should be scheduled to conventional Rig intervention. In order to optimize the hoists capability and performance to overcome this issue, we have to optimize based on priority and cost-effective selection criteria which will support to save the rig time & cost. Various advantages of hoists applications experienced in the last 2 years in ADCO include: Running scraperCorrosion and Cement Bond LogsFaster rig move.Work-over well repairs for single completion (well-kill, pulling old completion and running new completion)Well preparation for re-entry and sidetrack plug back to top of 7'’ linerESP work-over. Pulled old ESP pumpsFishing and milling operationsRun 7 "tie back liners.Plug and abandon wells partially or fully Abandonment (inactive string).Spotting and squeezing cement plugs and squeeze off old perforations, changing THS and X-mass tree.Cure Sustainable Annulus Pressure (SAP)Pressure test casingRun completion & special completion such as gas lift mandrels This paper presents methods of optimizing application of hoist in Abu Dhabi onshore fields by modifying enhanced well selection criteria based on the operation experiment and avoid production loss to sustain our field development plan. This implemented strategy benefit the optimization of number of workover wells which will increase in next five years scenarios, which in turn is expected to utilize rig cost savings. In addition, the new selection criteria will create "fit for purpose" solution to overcome these challenges of existing workover wells with less time and complication