The loss of functionality of the surface controlled subsurface safety valve (SCSSV) due to blockage of, or damage to, the hydraulic control line can present a major problem to Operators. The subsequent loss of hydraulic pressure to the valve means the valve will close resulting in loss of production and hence alternative methods for re-establishing control of the SCSSV are required. Performing a full scale work-over to replace the inoperable control line can require major expense and may not be justifiable in a mature well, while installation of a velocity or dome charged subsurface controlled safety valve may not meet well integrity or production requirements. Hence the preferred alternative is to install a System to Restore Full Safety Valve Functionality that is cost effective, restores production, and maintains well integrity requirements. The Tubing Retrievable SCSSV on well C-02 in the Sabah water of East Malaysia lost its functionality due to a leak in the control line. The SCSSV body was also found to be leaking from tubing to annulus which resulted in the failure to successfully lock open the SCSSV. Initially a major rig work-over had been anticipated to pull the tubing and replace the safety valve and control line. This operation would have required the use of a Hydraulic Work-over Unit (HWU) to perform the work which would have incurred a major expense. An alternative method was proposed that would allow replacement of the safety valve and control line, and to straddle the leak in the SCSSV body without pulling the production tubing or making changes to the wellhead configuration. This alternative method was a unique concept not previously attempted by any operator in Asia Pacific. This innovative approach would involve four elements: Installation of a Lock Mandrel and Separation Sleeve to straddle the leak in the SCSSV body & hold open the SCSSV flapper. Installation of a Wireline Retrievable Subsurface controlled safety valve with wet connector to connect to a new control line installed through the tubing (WDCL Safety Valve) which is anchored and located in the Tubing above the Tubing Retrievable SCSSV by means of a packer system. A new control line and special control line connector installed from the wellhead to the WRSCSSV through the production tubing. A new penetration in the Wellhead Lower Master Valve for the injection of hydraulic power fluid to control the WRSCSSV. These 4 elements provided a unique solution and the installation was successfully completed under a severe deadline. This was achieved by a high level of cooperation and collaboration between all parties throughout all phases of the project including and not limited to the planning, design and installation. This paper will describe in detail the system components and the decision processes and evaluations that led to the selection of this alternative solution. The collaborative efforts between the operator and two major service providers will be examined and discussed and the installation procedure described in detail. The paper will describe why the successful completion of this project marks a significant milestone in the remediation of older producing wells.
Sustained annulus pressure is an increasingly common well integrity issue encountered particularly in aging platforms. The issue is normally discovered via periodic wellhead maintenance programs or during monitoring by the production team. Subsequently, the wells integrity team will pursue well diagnostic via annular pressure diagnostic by manipulating and creating specific conditions to acquire information on the potential leak rate, leak path, and source of the leak. The probable culprit of the tubular integrity issues is due to completion or casing leakages, or failed cement conditions. The generic rectification technique available varies from rig to rigless method. Considering the low economic of the field & remote jacket location with a small footprint and limited crane capacity in Sabah waters, either the rig or workover option can be unfavorable. Therefore, the options available to remediate the sustained annulus pressure are limited considering the platform's design and operational setup. Historically, the team has attempted with a conventional pump and lubricate the annulus to mitigate the symptoms. However, the effectiveness was questionable as the pressure kept creeping up within a short period which urged the team to look into better technology solutions. With the limitations above, the team warrants a new holistic approach to resolve the sustained annulus issue. Annulus Intervention System (AIS) provides better fluid conveyance and circulation for better fluid displacement at the targeted depth. The AIS system has a smaller footprint as compared to a pumping or workover unit which is a major advantage for a small and remote platform directly applicable to the target Sabah asset. This paper will table out the step-by-step method that has been taken by the team to ensure the AIS system is engineered and tailored to rectify the sustained annulus pressure in a less than 500-meter square deck space.
Formation sand production is a major concern in brown field operations, especially as the field depletes and water production commences. There are many methods to control sand production in primary well completion; however, it becomes more challenging in producers where no primary sand control is installed initially, and it starts producing sand later in the well life. Selecting the right method for remediating these wells has become a hot topic with both Operators and Service Providers alike striving to discover effective and economical solutions for their brown-field operations. Currently, the solutions for through-tubing sand control in existing producers are screen hang-offs, through-tubing gravel packing1 (TTGP) and chemical sand consolidation. Through-tubing sand screen (TTSS) hang-offs above the producing zone, is an inexpensive sand control method. Unfortunately, these installations are typically short lived, often requiring regular well interventions due to screen plugging or erosion, or sand clean-out operations to remove sand accumulated in the production tubing. Alternatively, TTGP is a robust method to control sand production; however, more equipment is required to deploy the gravel pack which subsequently increases costs significantly in offshore applications. To simplify TTGP and make it economical, a major Interventions Service Provider devised a methodology to install TTGPs utilizing Slickine that reduces the overall installation cost tremendously. The methodology has been proven a great success in the US Gulf of Mexico where over 1,200 applications have been installed. The pilot implementation of slickline deployed through-tubing gravel pack (SL-TTGP) was executed in three S-Field wells in late 2018 which were shut-in due to higher than permissible sand production. These were challenging intervals in that they were uphole recompletions between cement packers in dual string 9-5/8" casing which had produced sand. The results from the installation proved that the methodology provides effective sand control and enables reinstatement of production from these wells. Further, the installations were achieved with lesser resources and at lower costs; less than half that of a CTU deployed TTGP. This success has led to further installations in the following year. This paper presents in detail the case study of the pilot implementation of SL-TTGP, key successes, as well as critical lessons learnt during execution and production phase. It includes the challenges, risks and their recommended mitigation plans, as well as the well performance comparison before and after the implementation both in terms of production and sand count.
This paper presents a case history in which a single-trip multizone sand control system was successfully deployed in Malaysia using a hydraulic workover (HWO) unit. The well consists of two (2) zones which were both treated and completed in a single-trip gravel pack system. This paper discusses in detail the design selection and operation, which includes the challenges faced and mitigation to overcome the challenges. All operations involved were completed with a significant time and operational cost saving to the operator. This was the first successful single-trip multizone installation using HWO globally. The sustained prolific oil production from this well affirms the success of the completion and gravel pack treatment method. These positive results highlight the importance of operator technical/operations personnel and service providers working as a team to develop the most appropriate solutions to the technical and operational challenges encountered.
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