As offshore oil and gas fields continue to mature, operators are faced with growing dilemmas regarding how to manage their late-stage, low-production wells. Large numbers of wells are stockpiled for abandonment, with the majority still in the U.S. Other major producing regions with significant numbers of idle wells include the North Sea, Asia-Pacific and Sub-Saharan Africa. Worldwide, this number of abandoned wells is growing at a rate of 8% to 10% per year.

Well decommissioning and abandonment is an inevitable part of the asset life cycle that represents a pure cost to the operator with no promise of boosted profits from increased production. While abandonment has traditionally been viewed as an isolated activity, it shares many operational synergies with late-stage workovers. Both operations are performed on older wells that have integrity issues, a lack of data for accurate cost estimating and limited deck space for intervention equipment and personnel on board.

The decision to extend a well’s productive life with a workover or abandon the well altogether depends on several factors, including the market price of oil and the regulatory requirements in place at the time. To that end, service providers can play a critical partnership role not only in helping operators make this decision but also in offering services that maximize resources and minimize costs and safety risks for both operations.

The Weatherford Well Intervention and Abandonment group, for example, has designed its service offerings to help operators make more informed decisions about which path to pursue. The business unit provides an integrated operational planning and execution service supported by engineering support from reservoir analysis and petroleum consulting to determine the remaining reserves and the best intervention processes to economically recover them. The service also provides synergies in the form of the same personnel, application expertise and equipment to help operators extend production to maximize late-life recovery and transition to decommissioning and abandonment operations.

Going rigless

Rig-free technology is one example of a synergistic service offering for late-life well intervention and abandonment. Weatherford’s rigless hydraulic pulling and jacking unit is engineered to ensure that jobs can be performed in the small spaces allotted and in short time frames. The unit integrates a variety of intervention services and products, including tubular running services, wireline, cutting and cementing tools, pumping equipment, and fishing and re-entry tools. And by using this unit for late-stage interventions and abandonment instead of drilling rigs, the operator is free to use the rigs to drill new wells.

In well abandonment applications, rig-free technology helps the operators execute the operation as quickly, safely and cost-effectively as possible. At the same time, the execution experience and application expertise of the field personnel help ensure that well abandonment is done correctly. This assurance avoids the need to revisit the abandoned well some time later to address a leak, which is often a significantly more expensive endeavor than the initial abandonment operation.

In some cases, the longer an operator delays abandonment, the more money it may have to spend to upgrade the offshore structure or to address well integrity and environmental risks ahead of actually abandoning the well. Rigless intervention also offers a proven alternative for operators who are idling wells and delaying abandonment for some future time to extend production.

This scenario has proven effective in many aging offshore assets, including a deepwater Gulf of Mexico well in which old chrome tubing had to be pulled out and replaced with new tubing. Weatherford’s intervention services were deployed on a pulling and jacking unit, which included the use of wireline to perform diagnostics and transport perforating guns downhole, slickline to carry tools and the bottomhole assembly, cutting tools to sever the pipe and equipment to cement the wells. The execution of this job avoided the use of rigs (and their associated high day rates), minimized downtime and allowed the wells to come back online with a 300% to 400% boost in productivity.

This is but one example of how operators can make safer and more cost-effective intervention and abandonment decisions for their maturing assets. The first and most critical step is to partner with a well services provider who brings excellence in operational planning, execution and a commitment to doing the job the right way the first time.