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Collaborating Authors
Successful Subsea Reentry Well Abandonments with Coiled Tubing Deployed from a Multiservice Vessel in the Gulf of Mexico
Rudnik, Alexander (Schlumberger) | Adams, Edward (Schlumberger) | Antunes, Arthur Da Silva (Schlumberger) | Shier, Scot (Schlumberger) | Norton, Thomas (M-I SWACO, a Schlumberger Company) | LeJeune, Ricky (M-I SWACO, a Schlumberger Company) | Dhorje, Dhananjay (Helix Energy Solutions) | Garber, Jaret Michael (Drilling Services of America) | Cartie, Bryan (TAM International) | Bounds, Nathan (TAM International)
Abstract Two subsea exploration wells located in the Gulf of Mexico at water depths of approximately 1,800 ft had remained temporarily abandoned while waiting on further decision since 1997–1998. When the current operator decided to permanently abandon those wells, the procedure called for a reentry by drilling out cement plugs set below the mudline inside the 9⅝-in. outside diameter (OD), 8.535-in. minimum inside diameter (ID), casing and permanently abandoning the wells by isolating the annular space that communicated with the open hole and extended to the mudline. Operations had to be completed rigless using an intervention riser system (IRS) with a 6.31-in. drift ID. A system incorporating capabilities normally associated with costly rigs was developed. It included a 2⅜-in. OD coiled tubing (CT) deployed from a multiservice vessel. To overcome challenges associated with milling cement using undergauge mills and possible pressurized gas trapped beneath the plugs, a two-step approach leveraging a 4.5-in. OD pilot mill bottomhole assembly (BHA) followed by a 5.9-in. OD mill and 8.3-in. OD underreamer BHA was implemented. A biopolymer-based milling fluid was selected to increase the solids carrying capacity and facilitate hole cleaning at low annular velocities (limited by friction losses through the CT workstring). A fluid management system provided a closed-loop solution for controlling fluid properties while removing solids from the system. The annular spaces were isolated by using a combination of decentered casing perforations, inflatable cement retainers, and latex cement systems. The cement was optimized to reduce recipe variations for different placement depths and bottomhole static temperatures. All cement plugs were successfully drilled out and the milling fluid provided good hole cleaning performance without any stuck pipe events. All fluids and tools performed as expected. The 9⅝-in. × 13⅜-in., 16-in. × 13⅜-in., and 20-in. × 16-in. annuli were isolated, and permanent abandonments were completed in accordance with the applicable regulations. The project required multiple service lines to work synergistically. Careful planning and seamless communication between all parties involved were key to ensuring optimal efficiency and safety while reducing the overall operational expenditures. The collaboration instilled between all the project stakeholders delivered incident-free operations at the lowest total operational cost, which came below the authorization for expenditures of each well as compared to rig-based abandonments. Although reentry well abandonments are not new to the industry, there is no history of such services performed inside large casings with CT from a multiservice vessel through an IRS with minimum ID restriction. This study details the engineered solutions and methodologies that enabled successful operations. It also discusses the project parameters, examines the operations, and proposes the lessons learned to serve as a benchmark for future such projects.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.55)
- Well Drilling > Casing and Cementing > Cement formulation (chemistry, properties) (1.00)
- Well Completion > Completion Installation and Operations > Perforating (1.00)
- Well Completion > Completion Installation and Operations > Coiled tubing operations (1.00)
- Health, Safety, Environment & Sustainability > Safety > Operational safety (1.00)
Plugging & Abandonment of Multiple Zones in One Run Using Perforate Wash and Cement on Hydraulic Workover Unit
Yang, Shahril (Petronas Carigali Sdn Bhd) | M. Yusoff, M. Hatta (Petronas Carigali Sdn Bhd) | Abdullah, Ismail Aslam (Petronas Carigali Sdn Bhd) | M Ros, M Ikhranizam (Petronas Carigali Sdn Bhd) | Devadass, Lingges (Petronas Carigali Sdn Bhd) | Othman, Azmi (Archer – The Well Company) | Stokkeland, Thore Andre (Archer – The Well Company) | Matthews, Parker (Archer – The Well Company) | Sainuddin, Abdul Karim (Reservoir Link Sdn Bhd)
Abstract Objectives/Scope Perforate, Wash & Cement (PWC) is a method developed over the past decade to help increase efficiency in plugging & abandonment of wells. The method has helped operators world-wide to save time and cost in plugging and abandonment operations by cutting down time for setting full lateral barriers. This technique can also be used to set permanent lateral barriers for slot recovery operations, and perform well repairs on workovers where there is sustained casing pressure. The technology is used to set lateral barriers to cure the sustained casing pressure, and enable the operator to put the wells back into production. The integrity of the well is restored and significant value is generated. However the technology has previously been limited to setting one barrier at the time. The unique challenge for this well on the Platform Alpha, offshore Malaysia was that two zones had to be isolated in one run. The distance between the two zones was almost 100 meters. A significant challenge, with a significant upside. The execution was using Hydraulic Workover Unit (HWU) and overall 14 plugs completed (for 14 wells). Methods, Procedures, Process The method has several critical success factors that need to be tailored to be able to produce a high quality result, especially with this unique challenge of plugging and abandoning two different zones in the same run. Optimization of the Tubing Conveyed Perforation (TCP) System to be able to balance hole size, geometry and density in order to create the ideal communication path into the external annulus was paramount to the success of the job. The TCP needed to also take into consideration casing size, weight and metallurgy to ensure that downhole conditions are simulated as accurate as possible, increasing the chance of successfully meeting the perforation criteria that has been optimized. Washing parameters needed to be optimized to be able to create high annular velocity for efficient hole cleaning and debris removal. This optimization takes into consideration the fluids density and rheology, ensuring that the mud system has the correct properties to suspend the debris for removal at surface. The compatibility and stability of the fluids and mud condition prior to cementing operation is also critical. The cementing operation on this well was a unique, tailor-fit engineering project, with the end goal and intention of being able to isolate two zones approximately 100 meters apart at the same time. The cement & spacer properties were important here due to possible gas, and high chance of losses into the formation after perforating, and during washing. The volumes, operational parameters and execution were critical to get the two zones efficiently plugged and abandoned in one run. This paper describes the extensive work that has been performed to plan and execute the successful plugging and abandonment of two independent zones using the Perforate, Wash and Cement technology; and in the process, saving several days of rig time, gaining significant value for the customer and setting a new benchmark for efficient plug and abandonment operations for the global market. Results, Observations, Conclusions The system testing of the TCP Gun system resulted in an optimum Exit Hole Diameter (EHD) and exit hole geometry tailored for this specific wellbore size, weight and metallurgy. The washing was efficiently carried out with high amounts of debris over the shaker system and a declining standpipe pressure was observed indicating a very successful washing of the perforations. The cement operation was flawlessly executed according to the planned operational parameters with no losses or operational challenges. The two zones were effectively isolated in 2.5 days. This fantastic result not only significantly lifted the efficiency of the Platform Alpha Plug & Abandonment operations, but also set a new benchmark for the Perforate Wash and Cement Technology globally. By isolating two independent zones in one run using the Perforate Wash and Cement Method, the technology has proven that within an already established methodology, there is still capacity for further progression and evolution of the technology. A one team effort between operator and service companies made this possible and in the process, established a solid blueprint for future efficient, safe and reliable operations.
Abstract Objectives/Scope The Perforate, Wash and Cement technique has been widely implemented in the remediation of annular cement in recent years, with the application gaining increasing confidence within the Well Integrity, Plugging and Abandonment sectors. With the increase in confidence in the technique to successfully remediate annulus cement comes the evolution of the process; pushing of limitations to meet new and previously challenging plugging and abandonment projects with confidence. The first attempted and successful ‘Closed System’ type Perforate, Wash and Cement of Dual Annuli is discussed and evaluated in this paper as an effective mean for environmental plugging and abandonment. Methods, Procedures, Process For the dual annuli application to be successful, the perforation of 10-3/4" and 13-3/8" casings must be effective without damaging the 18-5/8" casing to ensure efficient hydraulic communication that allows for washing out of annular debris and placement of cement across both annuli and this was verified by a full system test of the charge. Utilizing a ‘closed system’ (cup tool) perforate, wash and cement method enables constant communication between the isolated swab cups and the annulus behind the perforated casing during the process of washing. As a result of this specific methodology, the amount of annular obstruction is visibly confirmed from surface using standpipe pressure variations long before any debris is seen at surface. The reduction in standpipe pressure over subsequent washing pass is evidence that annular debris has been removed and this is visually confirmed by debris at surface. Dual annuli washing introduces additional uncertainty regarding effectiveness of washing within the second annulus and the effectiveness of this has been verified by both Computational fluid dynamics analyses (CFD), and full scaled yard test. Results, Observations, Conclusions Large volumes of debris consisting of approximately 30% formation cuttings / metal and 70% cement were observed at surface throughout the washing sequence. Cement was efficiently placed using the ‘Pump and Pull’ method. Utilizing the ‘closed system’ benefit of the cup tool, fresh cement was placed across the entire perforated interval ensuring the highest chance of a successful cement bond. Post-execution verification was performed on the cement plug and validation of successful placement of the plug was confirmed. Volumetric analysis verified the effective placement of cement into the 10-3/4", 13-3/8" and 18-5/8" annuli.
- Europe (0.30)
- North America > United States (0.28)
- Asia (0.28)
Abstract To meet rising global energy demand, the oil and gas industry is growing at an unprecedented rate. As mature oil and gas fields reach end-of-life, safe and cost effective abandonment techniques are now and will continue to be a critical part of the industry. Ineffective abandonment methods are a serious economic and environmental liability to an operator, particularly one having wells with surface casing vent flows. The operator's Foothills fields, located in central Alberta, Canada, are home to some of the harshest downhole producing environments in the country. Foothills wells are deep (>3500 m true vertical depth), sour (5% to 90% H2S) and mature (1947 to present) with average well reserves of over 80 million standard cubic meters of gas. They experience sulfur, iron sulfide, calcium carbonate and sodium chloride deposition. Saline water influx causes corrosion of the production tubing strings. Most of the wells have low casing cement tops leaving multiple porous geologic formations uncemented. These factors present many challenges during well abandonment operations. A well abandonment campaign for these fields began in 2011 and will continue for many years. To date over 40 wells have been abandoned. This paper will describe best practices learned, as well as "game changing" strategies that have led to significant cost savings and reduced operational risk. These include bullheading foamed cement to abandon the producing zone prior to moving in a service rig. This is followed by a "one-trip" abandonment utilizing through-tubing perforating and bradenhead cement squeezes with high pressure, slow-rate pumpers. The percentage of total well abandonment cost savings will be presented for each strategy. The principles for choosing cement squeeze intervals for the isolation of porous zones, and the success rates of surface casing vent flow shutoff will be discussed. This paper will also present data from cement plug drillouts which show that cement platforms are not required beneath a balanced cement plug in near vertical wellbores. These practical applications will reduce costs, lower risk exposure and lead to improved results in downhole abandonments.
- North America > Canada > Alberta (0.35)
- North America > United States > North Dakota > Burke County (0.24)
Novel Approach to More Effective Plug and Abandonment Cementing Techniques
Ferg, Thomas E. (ConocoPhillips Norway) | Lund, Hans-Jacob (ConocoPhillips Norway) | Mueller, Dan (ConocoPhillips Houston) | Myhre, Morten (HydraWell Intervention) | Larsen, Arne (HydraWell Intervention) | Andersen, Patrick (HydraWell Intervention) | Lende, Gunnar (Halliburton Norway) | Hudson, Charlie (MISwaco Norge AS) | Prestegaard, Cato (Halliburton Norway) | Field, David (Halliburton Norway)
Abstract The effectiveness of a permanent abandonment plug is measured by its ability to bridge the wellbore cross section both vertically and horizontally, including all annuli, with a plugging medium which can withstand the rigors of the environment to which it is exposed (Figure 1 – Barrier Requirements). The most common method for placing a plug in cased hole with an uncemented annulus has required section milling of the casing, making a clean out run and underreaming of the open hole prior to placing a balanced cement plug. A new method is presented which creates a permanent abandonment plug through the use of a system which perforates uncemented casing, washes the annular space and then mechanically places the cement across the wellbore cross section in a single run. This paper outlines the design methods, laboratory testing and operational elements that were assessed during the development phase, as well as the results of field trials used to qualify this technique.