Rigless Well Intervention Using Tubing Patch Technology Helps Restore Inactive Wells

Abstract This paper provides in-depth analysis of a low-cost solution to economically sustain production and avoid high workover costs. This paper conducts the technical and economic analysis on the tubing patch technology that promises to avoid rig intervention for tubing repair. This paper will contain the technical application with risks of the available technologies and their economic benefit in completely avoiding rig intervention. It will also focus on the value of right candidate well selection. The six oil producers and water injectors wells selected with potential SAP-A/tubing leak, were inactive but important wells to achieve production target. The identification of candidate wells was the key to success. The investigation of wells included running logs as noise and multi finger caliper to identify exact leak point. Two different methods of permanent tubing patches were tried, one with Wireline and one via coiled tubing. All the wells,well integrity was restored, post installation evaluation was conducted via pressure test and noise log to confirm the success & savings of 30% over period of 5 years BP. Due to the business need to produce more and more hydrocarbons, activating inactive strings riglessly can save considerable amount of capex. Tubing Patch trials were conducted on 6 candidate wells and it lead 20% savings over 5 years BP. The wells with Gas lift Mandrels (GLMs) were the most critical for tubing patches. The key was depth correlation and accuracy of setting the patch. The high risk of having GLMs and chrome material made depth correlation risky. Many options using Casing collar, casing tally and GR/CCl while running the patches were used along with dissolvable plugs were used to ensure the patch is set at the right depth. Each technology posed certain benefits and challenges in terms of operational procedures, inner diameter after expansion restriction, collapse rating and latching mechanism. The best technology would be the one that can provide unrestricted uniform inner diameter with sufficient collapse and burst rating and economically viable to be used. Consequently, the tubing patches were installed riglessly using coiled tubing and wireline which avoided well intervention and saving huge CAPEX of 20% per well in drilling CAPEX and around 20% bbls/oil per day in production restoration. The selection criteria matrix is now a standard format used in Well Integrity management system to select candidate wells for tubing patch technology. Each candidate well were this tubing patch technology was used promised to save huge MM in CAPEX, depending on the type of well and 30 days average in well duration.Multiple wells were restored with tubing patch technology and thus avoided the expensive workover costs. Reduction of Rig mobilization and over cost for SAP A wells due Tubing leakage repair by using a rigless solution called tubing patch depending on different factors that can extend the life cycle of the wells for low cost and optimization for integrity results. Current challenges to integrity issues include non-productive time for wells and operations when carrying out a traditional work over. The new approach is based on wells that have been identified with sustainable annulus pressure in the A annulus (SAP "A") due to tubing leak. Those wells have been evaluated following the industry best practices and the company Code of Practice. The investigation started on identifying the tubing / Annulus integrity with the different procedures of pressure test, If the leak is established, then the use of leak detection logs (LDL) with an e/L unit to identify the exact location of the leak. At the same time a MultiFinger caliper logs (MFC) is the great use to evaluate the condition of the tubing ID, identifying the extension of the corrode section. During the evaluation of the trial found dictate the selection between tubing patch or a straddle solution. For the tubing patch solution, the requirement is to have one (1-2) leak point in the string, For the straddle solution the requirement is to have multiple leak points (to add the appropriate spacer length), be retrievable and allow accessibility and longevity of the well life cycle. The selection of the rigless solutions for issues due to tubing leak will help in reducing rig mobilization costs and non-productive time and reduce well inactivity of the production/injection of the well. The implementation of the tubing patch was evaluated on 3 different wells. Where well 1 as WI well with 2 identify leak points and solution for 2 different patch sections with a positive result on the Annulus pressure test post patch installation. The 2nd well as WI well with 1 identify leak points with a positive result on the Annulus pressure test and LDL post patch installation. The 3rd well as OP/GLM well with 1 identify leak points with a negative result on the LDL post patch installation. As per the badly corrosion levels in the tubing. The observations found during the resolution and application of these solutions, were the level of corrosion as a limiting factor when selecting the availability and suitability of these solutions. 3 Well were used for the development of the trial and just 2 provided positive results, the 3rd well fails. The utilization of these technologies can enhance the operational side to solve the leakage of tubing strings in short time of inactivity, generating revenue and new procedures for barriers evaluation in different type of string and wells. Providing this solution reduces the utilization of rigs and huge cost related for just recomplete the well, instead of the extension of the life cycle.