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Abstract Despite new deepwater project economics being strongly challenged by the halved oil prices, it is expected that the ongoing projects will continue, given the large, long-term investments that have already been made. In this challenging market environment, operators are required to reduce operating costs to balance expenditures with available cash flow. With the reduction in operator spending, coiled tubing (CT) service companies are further pressed to reduce service charges. Lowering service rates is not the ultimate solution because it neglects to consider a prevalent factor that often relates to excessive expenditures: inefficient performance. Improved operational efficiency holds significant cost-saving potential. Efficient performance in the areas of equipment loading, offloading, rigging up, pressure testing, in-hole operations, and rigging down enables substantial financial reward in the form of time savings. The importance of efficiency improvements in deepwater vessel-based CT operations, along with the key areas of improvement and performance solutions, were explained in previous papers, Ottolina et al. (2016) and Rudnik et al. (2014). The objective of this study is to transform efficiency improvement into a repeatable process that can be applied to every aspect of CT operations to decrease operational risk, enhance performance and reduce intervention cost. Low-performance areas and locations of recurring non-productive time (NPT) were addressed with remedial work plans. Meanwhile, high-performance areas were analyzed to record the best practices for efficient execution to realize efficiency gains for the campaign's duration. These best practices were applied to areas of mediocre performance to elevate the percentage of tasks performed on an efficient level. To ensure continuous improvement and unbiased performance review, a performance tracking system and various performance metrics were created. To ensure consistency of performance and continuity between three offshore crews, the development of standard work instructions, process flow charts, and templates were created and deployed. The development of a total efficiency solution provided the framework for a step change in performance for seven well intervention operations. A consistent, systematic approach to CT operation efficiency improvement has resulted in reductions of 60% for average pressure testing time, 63% for BHA makeup with break test, and 30% reduction in rig up and rig down series. Additionally, improved consistency has accompanied increased performance as the online pressure testing success rate improved from 64 to 95%. These efficiency gains currently provide an estimated 22 hr total time savings for a typical 7-day CT operation.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.94)
Deepwater Riserless Operations with Coiled Tubing in the Gulf of Mexico: An Innovative, Safe, and Efficient Plug-and-Abandonment Technique
Ottolina, Renny (Travis Gortmaker - Coil Tubing Services a Schlumberger Company) | Torres, Carlos (Travis Gortmaker - Coil Tubing Services a Schlumberger Company) | Rudnik, Alexander (Travis Gortmaker - Coil Tubing Services a Schlumberger Company)
Abstract The future of exploration and production (E&P) operations in the Gulf of Mexico (GoM) is focused on deep water, that is, >5,000 ft [1,524 m] water depth. As the industry pushes the envelope to reach deeper reservoirs, subsea wells have become an important part of the offshore production. Although subsea completions may offer significant economic and environmental advantages over seafloor-founded structures, they require floating drilling or well intervention vessels to enable wellbore access should a workover operation be required to maintain production at an economic level or even to plug and abandon (P&A) the wells once they become uneconomical to produce. Interventions and P&A operations are very costly and may involve multiple services. The P&A of subsea wells represents no financial upside to the operators, other than the possible recycling of the subsea trees. Consequently, reducing costs and avoiding future environmental liability are the prerequisites for successful subsea decommissioning. Riserless subsea P&A operations are often completed by setting the plugs with drillpipe after the production tubing is removed with the rig. As part of the operational improvement process, a coiled tubing (CT) service company evaluated the option of performing this task using the riserless CT technique from a multiservice vessel (MSV) after the zonal and casing isolation packer had been successfully set and tested. This technique would allow the operator to save time to complete these operations, thus reducing the cost. Between 2010 and mid-2015, the CT service company has successfully completed 18 riserless subsea interventions at well depths ranging from 4,900 ft to 21,000 ft [1,494 m to 6,400 m] and water depths from 4,600 ft to 7,000 ft [1,402 m to 2,133 m]. Riserless wellbore access with CT has proved to be an efficient P&A method that has helped reduce operating time by up to 40% as compared to riserless workover rig-based operations. Detailed engineering and planning as well as continuous improvements have allowed implementing the CT riserless technique in accordance with the Bureau of Safety and Environmental Enforcement regulations.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.34)
2 3/8; and 2 7/8 OD Coiled Tubing Operations in Gulf of Mexico GoM Shelf: A Safe, Reliable, and Efficient Way to Prepare for Re-Entry of Wells to Conform to New BSEE Regulations
Torres, Carlos (Schlumberger Coiled Tubing Services) | Ottolina, Renny (Schlumberger Coiled Tubing Services) | Rudnik, Alexander (Schlumberger Coiled Tubing Services) | Creppel, Carl (Shell) | Bergeron, Ernest (Shell) | Broussard, Mike (Shell)
Abstract Since the Bureau of Safety and Environmental Enforcement (BSEE) released and implemented the updated version of the Code of Federal Regulations (CFR) in recent years, Operators now have the need to reenter wells that had been deemed as abandoned in the 1980’s, and perform operations to comply with the updated regulations. All of these wells have surface plugs (either cement plugs or cast iron bridge plugs) that require milling in order to access the wellbores to be abandoned. The use of a pulling unit is generally the method used for these abandonment operations. However, the risks of having pressure trapped below those surface plugs, and the ability to maintain well control during milling operations with the pulling and jacking units (PJU) poses a great concern to the Operators. Upon evaluation, Shell decided to use large outside diameter (OD) coiled tubing (CT) to mill the surface cement plugs and the cast iron bridge plugs. The use of CT enabled several operational advantages, such as the ability to handle potentially live well situations safely and efficiently, faster operations to mobilize (mob) from well to well, the use of larger bottom hole assemblies (BHA) with mills manufactured to drift the different casings 7", 9 5/8" and 10 ¾" inner diameter (ID), ensure optimal downhole motor (DHM) performance and to provide efficient removal of solids from the wellbore back to surface. This paper describes the CT operations performed on two shallow waters platforms projects in the GoM for Shell, where a total of 9 wells were intervened using 2 3/8" and 2 7/8" OD CT. The challenges encountered together with the developed solutions, equipment used, lessons learned are also discussed. Full compliance with BSSE regulations for well abandonment was the final result.
Coiled Tubing Operations on a Multi-Service Vessel for Deep Water Well Interventions in the Gulf of Mexico: A Decade of Experience
Rudnik, Alexander (Schlumberger Coiled Tubing Services) | Torres, Carlos Alberto (Schlumberger Coiled Tubing Services) | Ottolina, Renny Alexis (Schlumberger Coiled Tubing Services) | Rourke, Jonathan (Helix Well Ops US.) | Barber, David (Helix Well Ops US.)
Abstract Demand for subsea well intervention work has continued to be strong for the last 10 years. Even though subsea well interventions from an intervention vessel represent only a fraction of the total well workover activity in the Gulf of Mexico (GoM), its operating environment poses challenges in meeting economic goals for the Operators. The Q4000, a purpose-built, multi-service dynamically positioned (DP) vessel, was first introduced in the GoM in April 2002 and has been extensively used to meet demand of subsea well intervention and abandonment. Coiled tubing (CT) intervention, along with Slickline and Electric Wireline, has been instrumental in supporting the Q4000 ability to maintain safe, reliable, and cost efficient subsea through tubing well interventions in such a demanding operating environment. This paper will summarize the operational experience and will focus on the CT-specific best practices and lessons learned that have resulted from over than 10 years of continuous operations on the Q4000. The document will highlight critical stages in the learning curve, standardized procedures, synergies between the CT and the Q4000 crews, and their impact on safety, efficiency and cost reduction. The paper will also discuss the needs for further improvements that will be required to meet the new challenges that subsea well intervention will be facing in the future.