The ever-pressing dilemma of meeting increased global demand for hydrocarbons as offshore oil fields continue to mature is pushing operators to seek late-stage intervention solutions that can revitalize aging marginal wells and bring them back online to extend production.

In the past, production companies could choose to abandon a well once it shifted from asset to liability, but that is no longer the optimal solution. In today’s environment of hard-to-tap resources and the growing consumption of oil and gas, operators are increasingly looking for a way to give old wells a new lease on life with continued production and maximized recovery.

Globally, an estimated 20,000 idle wells have been identified for abandonment; 45% of them are in the highly regulated Gulf of Mexico (GoM). Complicating the situation in the GoM are regulations mandating that if a well has not been productive for three or more years, the operating company must put forward a plan, including a timeframe and methodology, to abandon it. As they attempt to avert an expensive plug and abandonment (P&A) operation that will permanently shut down their well’s production, more companies are considering late-stage interventions that allow them to recomplete those idle or marginal wells and continue producing.

In response to this emerging trend, Weatherford has expanded its rigless hydraulic pulling and jacking unit (P&JU) technology to carry out late-stage interventions as well as P&A operations. The P&JU can serve as the foundation for successful late-stage intervention operations on aging wells, allowing the client to significantly extend production and the life of a well. This type of workover operation has been successfully completed with the unit in the GoM and elsewhere, notably the Asia-Pacific region.

The P&JU uses a broad range of equipment, technologies, and resources to safely and efficiently address the challenges associated with critical offshore late-stage intervention operations. The rigless design allows placement on offshore platforms that don’t have existing derrick systems, have downgraded their derrick systems, or have damaged derrick systems. The modularly designed unit has a hydraulically powered telescoping mast that sits directly above the well center and has both an integrated jacking system and power swivel stand that require no additional rigup time.

Enhanced well control

The P&JU also is highly mobile and can skid from well to well with a self-clamping skidding system, providing greater flexibility to address multiple well configurations. To safely contain wellbore pressures, the design allows a BOP to be placed under the unit, making it fully compliant with regulatory requirements.

Since the P&JU was introduced in 2006, its support risers have been enhanced with a new undercarriage design to handle multiple BOP configurations. The P&JU is deployed with a BOP stack and can now accommodate up to three rams – a blind ram, shear ram, and drillpipe ram – and an annular to redirect pressure and fluid down the flowlines. When moving from well to well, the BOP can be disconnected from the wellhead, held in the undercarriage, and transported with the P&JU instead of being moved separately, achieving both mobilization efficiency and cost benefits.

The technology is being successfully used to rejuvenate wells nearing the end of their life cycle. On one operation, degraded and clogged chrome tubing had caused declining production, creating an economic liability. The operator wanted an integrated application to be performed through a workover, one that involved changing out the tubing to bring the wells back online.

Due to space limitations for some platforms, operations can be particularly challenging due to the tight location and restricted space for equipment. The P&JU was engineered to ensure that jobs can be performed in the small spaces allotted and in short timeframes. Compact and lightweight, the P&JU is an enabling tool that integrates a variety of Weatherford intervention services and products, including tubular running services, wireline, slickline, cutting and cementing tools, pumping equipment, and fishing and reentry services to recomplete wells and return them to production at an economically sustainable rate.

Integrated intervention

The P&JU in this case used tubular running services technology to pull out the old chrome tubing and run new tubing into the wells without incident. The unit also facilitated the use of wireline to perform diagnostics, gain exposure to the formation, and transport the perforating guns downhole. Slickline was used to carry tools and equipment, such as the bottomhole assembly, downhole. Finally, the unit enabled the use of cutting tools to sever the pipe and equipment to cement the wells.

This case proved to be a safe and cost-efficient alternative to a conventional rig-based operation, a workover or snubbing unit, or a crane-based job. Rigs offer all the capabilities to conduct a late-stage intervention such as relatively fast trip time in pulling tubulars and large-capacity fluid storage. But with high day rates, rigs can be very expensive and require extensive logistical planning.

With its small footprint, the P&JU can effectively bridge the gap between rig- and crane-based methods, able to work in the limited available space while providing similar capabilities to that of a full-blown rig. The unit has the ability to pull 72,575 kg (220,000 lb) in 18.3-m (60-ft) increments, has a jacking capability of 272,155 kg (600,000 lb), and facilitates the support of 1,890 m (10,000 ft) of 3½-in. drillpipe.

Once the P&JU was assembled on location, it operated independently from the crane; a crane was needed only to pick up and lay down the tubulars. The diesel-powered unit was not impacted by weather – a key advantage in reducing nonproductive time. The P&JU is American Petroleum Institute-certified to withstand winds up to 60 knots (69 mph).

Getting wells back online

As offshore fields continue to mature and the heightened regulatory climate expands globally, the late-stage intervention market grows. Rigless technologies that present viable alternatives to expensive and limited conventional methods are encouraging more operators to consider late-stage interventions that can bring aging wells back online. Other rigless solutions include light-duty work decks for tubular running and removal, which also provide the ability to section milling.

As more wells require mature intervention services, the need increases for safe, compliant, and cost-effective methods. With a proven track record in the GoM and deployment in other markets, P&JU technology is proving to be a reliable method for rigless well intervention services in maturing fields.

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