An arrest in the declining price of oil aligned with an increasing appreciation of hydrocarbons from governments such as the new U.S. administration means the focus for the industry is rightly fixed on maximizing recovery and production once again. However, despite recent indications of a return to commodity stability, the case for decommissioning remains as strong today as it was when oil dropped below $29/ bbl in January 2016, the lowest point in the current hiatus. Decommissioning represents a multibillion-dollar opportunity for the service sector at $13 billion per year by 2040.
Increases in global decommissioning activity will see about 600 projects targeted for disposal in the next five years. The U.S. Gulf of Mexico (GoM) has the largest number of platforms to be decommissioned, with more than 5,000 oil and gas structures in place. Initial levels across the U.K. and Norwegian Continental Shelf remain relatively low, with only 12 projects ongoing in 2015. However, that number grows as 186 projects are expected in the period up to 2025.
These key maturing basins have focused on the need for a robust decommissioning strategy, one that requires an appropriate approach and governance. With time, resources, technology and regulations all impacting the decision-making process, operators are increasingly looking for solutions to carefully manage their decommissioning liability.
Regulations, guidelines and policies vary between countries and companies, but when it comes to well abandonment, the onus is on the operator to meet and exceed the governing criteria, ensuring there’s no risk to the environment. The challenge for the industry is to do this safely, cost-effectively and sustainably.
The introduction of the U.S. Bureau of Safety and Environmental Enforcement’s (BSEE) Idle Iron Policy focuses on late-life disposal, requiring operators to decommission their facilities after they are classified as “no longer useful for operations.” This occurs after five years of nonproduction and where there are no plans for future development. Other recent examples of the increased focus on integrity can be seen with the American Petroleum Institute’s recommended practice 1171 for the integrity for gas storage wells and BSEE’s new well control changes to part 250 of the Code of Federal Regulations.
This governmental approach has been partially responsible for sustaining a stable decommissioning industry in the GoM. In the past decade about 130 platforms have been decommissioned per year, according to BSEE statistics.
A key objective has been turning industry best practices into legislation, with BSEE working alongside government branches and organized industry workshops prior to finalizing the revisions. A similar process is followed in the U.K. and Norway, where the industry contributes and suggests changes to guidance documentation.
Estimating the cost of abandonment remains challenging and involves consideration of asset size, complexity, history and information available. One issue can be a lack of well intervention history, including poor record keeping, varying data formats and changes in reporting systems. This can lead to lost or poor-quality data, equating to potential cost overruns during final abandonment.
This can be compounded by the scale of well integrity issues, particularly those caused by extending field life. Understanding the condition of a well is critical to minimizing any potential risk of uncontrolled releases while managing the cost. Abandoning wells with poor integrity is difficult and expensive. Technology can play a major role in removing some of these burdens. Monitoring and reporting the condition of a well—from production through to abandonment— will address several of these aspects. For example, Expro’s SafeWells well integrity software was specifically developed in partnership with operators to deliver an effective well management solution to improve communication, auditability and data quality.
If the well condition is unknown before the start of a campaign, a dedicated well investigation and preparation phase can be conducted prior to abandonment. This removes uncertainty as well as performing the initial steps of an abandonment program without the need for rigs to conduct costly well intervention (or in the case of subsea wells, the use of a light well intervention vessel). Once the well condition is known, the optimum methodology can be developed to minimize logistical costs and reduce the utilization of expensive equipment.
Expro has been involved in projects of this nature for several years, including a recent eight-well slickline campaign on Shell’s Armada Field in the central North Sea. This approach successfully delivered the program six days ahead of target and 27 days ahead of budget thanks to a combination of an innovative operational approach, a multidisciplinary crew and lessons learned from previous operations.
Traditional means of barrier verification still rely on a pressure test to ensure the barrier is leak-tight. Expro’s Cableless Telemetry System (CaTS) uses electromagnetic wireless reservoir monitoring technology to monitor reservoir pressure and temperature by transmitting data using the steel construction of the well as a signal conduit. The system was designed to monitor abandoned appraisal or suspended development wells by testing for interference and reducing uncertainties in connectivity. This proven technology can be applied to barrier testing in a number of different ways and is designed to reduce abandonment costs, improve safety and reduce uncertainty in verification.
CaTS was deployed in Norway to allow two deep barriers to be set and independently verified through the deployment of wireless real-time surface readout pressure gauges below the upper plug, allowing independent barrier verification to be proven (in compliance with the NORSOK D-010 standard). This technology has been used in Brazil in similar applications, for example, to prove swell packer isolation during well construction in deepwater environments.
It also can be successfully applied on suspended subsea wells when a light well intervention vessel is deployed to complete temporary abandonment prior to rig abandonment. Deployment of the CaTS pressure gauge below the shallow pump open plug allows the operator to independently monitor the status of the primary well barrier(s) for the duration of temporary abandonment, providing well integrity status pressure data for rig well abandonment operations. This allows the tubing to be pulled by the rig with a tubing hanger running tool, avoiding the cost of running riser and wireline equipment.
One operator estimated that utilization of this approach would save three days of rig time per well in a multiwell campaign, shortening the rig schedule by a month.
CaTS also can be used to monitor the status of suspended wells, which is increasingly important as regulators enforce new abandonment legislation and timings. Pressure readings for subsea wells can be retrieved by a standard vessel using a dunking transceiver, thus reducing inspection costs while improving monitoring capability (compared to ROVs). Another benefit of the system is its ability to monitor the short-term verification of the plug while overseeing the long-term integrity status of the primary well barrier.
Operators are increasingly aware of the value of effective abandonment, which can deliver large cost savings if planned alongside continued investment in technology. In today’s oil price this has been extremely difficult since capital budgets remain constrained and companies rely on adapting existing technology. While these solutions can meet the industry’s immediate need, further investment is required to deliver the economies of scale and increasingly complex large-scale abandonment and decommissioning programs.