Offshore Oil accounts for 30% of the world's liquid hydrocarbon production. As offshore platforms age, as is the case with some of the production facilities in the Gulf of Suez, these structures will have a increased load restriction, which makes it difficult to perform simple interventions, and forces the operator to deploy a Jackup rig or do a barge assisted operation. Some identified opportunities are not performed due to the high cost and the inherent subsurface uncertainty with brownfield assets. An alternative solution is a new generation intervention tool that allows signal transmission on conventional slickline wire. Real-time slickline (DSL) perforations use a unique technology to allow signal transmission on a standard slickline. The technology uses downhole battery-powered telemetry embedded in the downhole tool string. A radio-frequency (RF) antenna installed below the stuffing box is responsible for sending & receiving RF signals through the wire. The wire is coated with a proprietary engineered coating to ensure quality signal transmission and protects against corrosive wellbore fluids. The technology allows real-time depth correlation, pressure, temperature & vibration measurements while perforating. Moreover, the technology offers on-command explosive triggering, which improves safety over the older memory/timer version. Real-time slickline perforating was successfully introduced in the Gulf of Suez, accessing two platforms with structure load weight limitations that could not accept a conventional e-line unit. The optimized weight of digital slickline equipment was only 8 tons, compared to 35 Tons for e-line. Two wells were successfully perforated on two different platforms, adding 1200 BOPD at 10% of the rig-assisted intervention cost. The real-time slickline deployment enhanced the intervention efficiency and saved $950,000 in operating expenses. In addition to the successful deployment of several perforation runs without operational problems, the additional capabilities of DSL for surface readout (SRO) pressure & temperature data allowed the operator to optimize the time on the platform and maximize efficiency. The ability to add feedthrough jars to the string helped complete one job when the tool BHA struggled to get into the tubing after perforation. This capability is not available in conventional E-line. Real-time slickline (DSL) operations are the next generation for rigless interventions providing access to wells that e-line could not cost-effectively intervene and complete this task at a much lower cost.
Digital slickline (DSL) using radio frequency (RF) communications for on-command surface controlled explosive trigger tools has been available for years (Heaney et al. 2018). Unfortunately, the non-explosive electro-mechanical downhole power unit (DPU) setting tool could only run in timer mode, and all key performance indicators (KPI), including motor current & voltage, force and rod position were only available in the tool’s memory. The expansion of DSL services led to the development of a powered mechanical platform, and the primary tool upgraded was the DPU to an elite downhole power unit (EDPU). This enhancement allows for on-command surface control and real-time KPI sensor data that was formerly only in the tools memory. Also available are the real-time DSL data, including; casing collar locator (CCL), pressure, temperature, inclination, relative bearing, axial & radial vibration, and battery voltage & current that helps corroborate a successful plug set. Case histories presented will show how all the surface readout (SRO) data provide conclusive confirmation in-situ that the barriers set as planned, and provide a repeatable signature of a mechanical plug set. We will also show examples of plugs that exhibit the expected digital signature but did not pass a mechanical integrity test to confirm adequate isolation. Additional tools in the powered mechanical toolbox include an on-command release tool (ESRT) and a downhole anchor tool (EDAT). All devices can be run in combination if required, and each apparatus has a unique address with individual surface commands. The EDAT & EDPU combination expand intervention services with an extremely high push & pull force, which allows for pulling of subsea crown plugs, heavy-duty fishing, pulling retrievable plugs and many other applications. The EDAT can be set up to run in industry-standard 3 ½, 4 ½, 5 ½, and 7inch pipe sizes and can be modified to allow pulling of oversized crown plugs those outside diameters (OD) are more significant than the dimensions of 7inch pipe.
As the scope of deepwater operations increases, the need for cost-effective well servicing is paramount, particularly because of the continued challenges associated with current volatile commodity pricing. One of the first requirements on any subsea deepwater intervention with a horizontal wellhead production tree is pulling the subsea horizontal tree isolation lock mandrel plugs, commonly referred to wellhead or crown plugs. This can be a "show stopper" event if not planned correctly. Because of the critical nature of this action, the majority of operators follow a two-prong approach, with a primary plan of action and a contingency procedure, to help ensure barrier removal proceeds as planned. Although successful removal of the crown plugs is the principal concern, it needs to be completed cost-effectively for the intervention to obtain approval. The advent of digital slickline (DSL) allows surface readout (SRO) monitoring during the removal and installation of these barriers to provide an increased level of confidence during this important phase of the operation. This paper outlines case studies of the real-time sensors available with the RF communication DSL system that was highlighted previously (Heaney et al. 2018) for pulling and setting these wellhead or crown plugs in deepwater Gulf of Mexico interventions using the traditional jarring approach. Two brands of crown plugs are available on the market, and although both pull the same, there is a difference in the installation procedure and each plug or lock has a unique SRO digital signature. Additionally, the straight pull battery operated extended-stroke downhole power unit highlighted in McDaniel et al. (2008), Clemens et al. (2014), and Babin et al. (2015) offers a cost-effective contingency that can be deployed on the small-footprint DSL unit. This setup allows starting the operation using the traditional jarring approach, and if required because of high hydrostatic forces, the operation can easily move to a straight pull contingency without rigging down the DSL unit for maximized wellsite efficiency. New developments as the downhole power generator was ported to DSL are discussed, notably on- command motor controls and SRO, which was traditionally only available in memory. A downhole anchor was added to the toolbox, which can be run in combination with the downhole power generator to expand effectiveness, as new production trees might not allow for a no-go landing shoulder. To address the increased water depths, the 3.59-in. extended-stroke downhole power generator was upgraded to 80,000 lbf pulling force.
The Kuparuk River unit (KRU) on the North Slope of Alaska is a maturing asset providing a variety of well intervention opportunities necessary to maintain production. Because of the high well count, interventions need to be efficient, and the traditional slickline and electrical line model are being challenged. The primary concern is the multiple rig ups and rig downs to complete the scope of work, but there are also local concerns, such as maintaining a workable equipment schedule in a cold-weather region. Another unique feature of the KRU is that many of the wells have scale deposits. Digital slickline (DSL) has been successfully used in the KRU and was highlighted in previous papers (Wiese 2015). The ability to have real-time depth correlation with a casing collar locator (CCL) and optional gamma ray (GR) during slickline runs and completing the traditional electric line services (i.e., packer set, perforating, etc.) is a game changer that dramatically helps improve intervention efficiency. A previous challenge was maintaining real-time communications in areas where there is excess scale buildup. To circumvent this issue, a new protocol was developed using a radio frequency (RF) antenna to provide half duplex communications with a coated slickline. This methodology doesnot require the tool housing to contact the tubular to complete the signal transmission. In 2017, more than 400 digital subscriber line (DSL) runs covering a wide variety of tasks were successfully completed, including removing and replacing gas-lift valves, fishing packers, string shots, perforating, setting packers, and patches. An interesting result of the KRU digital slickline interventions was that approximately 60% of the runs were slickline centric involving jars and 40% were considered e-line replacement services. This trend suggests that a successful product should be able to complete all typical slickline runs to maintain the efficiency advantage.
Through-tubing bridge plug (TTBP) service is a common e-line well intervention service for isolating lower non-productive zones for improved production or plug and abandonment. Traditionally, this service was only run on e-line, as it requires a unique electro-mechanical extended stroke setting tool, to set these types of barriers. This paper discusses the challenges of developing a new design of the TTBP, deployed on Digital Slickline (DSL) to help optimize service costs. System-level analysis was adopted to analyze the current e-line TTBP service and identify challenges to DSL deployment. In general, these plugs have extremely high-expansion ratios (2x to 4x) compared to other wireline set barriers as they have to pass through tight downhole restrictions in the completion before passing into the casing. As a result, these plugs have an exceptionally long setting stroke, requiring a specific setting tool with high power demands. The high expansion ratio of the TTBP limits pressure rating and this type of barrier demands a cement cap on the plug to complete the intervention. DSL cannot send power from the surface; therefore, it has electrical power budget limitations. The right balance needs to be found between the stroke length and the available power to achieve a successful plug. The elastomer stack and the backup petal assembly were significantly redesigned to achieve an acceptable expansion ratio while minimizing stroke length. This feature allowed for the development of a battery-powered setting tool with a shorter stroke length. Running the service on DSL lets the operator confirm depth correlation before setting the plug and real-time feedback from downhole sensors to ensure an in-situ quality plug set. Moreover, digital slickline provides accurate bottom-hole temperature, which is critical in achieving a suitable cement plug. The paper will present results from field trials showing the cost savings of running these plugs on DSL compared to e-line.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.