Going rigless

Audrey Leon chats with Schlumberger, Baker Hughes and Weatherford to learn about the latest technologies available for rigless plugging and abandonment operations.

Rig-Free heavy-duty pulling and jacking unit. Photo from Weatherford.

OE: Please describe your rigless abandonment offering.

Euan Stephen, rigless intervension system (RIS) manager, Baker Hughes: [Baker Hughes] currently has two different units within our rigless abandonment fleet, the Mastiff Rigless Intervention System (RIS) and the Retriever Jacking Unit System (JUS). The RIS is a portable, modular, mast-style unit with a 320-tonne pulling capability delivered via a winch and travelling block. This unit can be configured in several different ways, depending on the operator’s requirements. This includes provisions for well control and drillpipe racking to reduce in-hole tripping time. Once installed at the wellsite, the RIS has full X-Y axis skidding capability. This capability requires the unit to be rigged up only once to gain access to all well slots in a short time. The JUS is also a modular design. The unit’s pulling capability is delivered by hydraulic cylinders and has a maximum pull of 200-tonne. Integrated into the unit are power tongs, a guillotine saw and a dual-drill machine, all essential equipment in the tubular recovery process. The unit also has full X-Y axis skidding ability to deliver the same time-saving, single-rig-up benefits as the RIS.

Rod Smith, integrated well abandonment global operations manager, Schlumberger: In the current landscape of abandonment, higher well complexity, increasing regulation, and well integrity issues have all combined to increase the challenge of achieving full isolation using a rigless methodology.

This requires portfolios of technology to address industry needs and ensure robust barrier installation and verification.

Schlumberger has leveraged a portfolio of technology for plug and abandonment (P&A) applications, such as LIVE digital slickline services, for more accurate depth control, confirmation of jarring, and risk reduction through head tension and on-demand release for stuck tools. These services provide electric line measurements and capabilities, but with the smaller footprint of slickline.

Further enablements in wireline include a mechanical services platform, ReSOLVE instrumented wireline intervention service, to retrieve stuck plugs or tools from wells and enable access. The system can also mill scale and obstructions to prepare the well for cementing.

Advancements in coiled tubing (CT) technology have also allowed more downhole confirmation of barrier placement through the use of ACTive real-time downhole coiled tubing services.

Currently, Schlumberger is working on several new technologies focused specifically on rigless abandonment. Specific to subsea wells, the Subsea Services Alliance (a collaboration among Helix, Schlumberger, and OneSubsea, a Schlumberger company) is developing the first riserless open-water abandonment module (ROAM) system (OE: April 2017). Enhancing the capabilities of the well intervention vessel by providing 18¾-in full-bore access, ROAM is deployed after the reservoir isolation phase and allows tubing to be pulled in open water safely and with environmental containment. Once the tubing is removed, the well intervention vessel can perform the upper abandonment. The system offers a flexible and cost-effective alternative to rig-based P&A well isolation more safely and with environmental containment.

ROAM provides 18 3/4-in full-bore access with the ability to capture contaminants or gas and circulate them back for safe handling to surface. Photo from Subsea Services Alliance.

Delaney Olstad, global business development manager – well abandonment & intervention services, Weatherford: The Rig-Free pulling and jacking unit (PJU) is an integrated system for efficiently completing offshore well abandonment and intervention operations. These systems are designed to complete tasks normally performed by a jackup rig or workover unit, but at a lower cost and with a higher degree of safety. It is well-suited for pulling tubulars and conductors on platforms with downgraded structural capacities and in situations where space is limited.

To accommodate a wide range of operations while being adaptive to platform limitations, Weatherford has two versions of the PJU. Each PJU has a hydraulically powered telescoping mast, which sits directly above the well center and incorporates a power swivel for rotating pipe and equipment. There is also a compact yet powerful jacking system integrated into the work floor. On the heavy-duty pulling and jacking unit, these elements offer a pulling capacity of 220,000 lbs (99,790 kg) in 60ft (18.2m) increments and a jacking capacity of 600,000 lbs (272,155 kg) in 5ft (1.5m) increments. The light-duty PJU provides a pulling capacity of 35,000 lbs (15,8676 kg) with a stroke of 44ft (13.4m) and can jack in 5ft (1.5m) increments at up to a capacity of 1 million lbs (453,592 kg).

OE: Please give an example of where it has been used and when.

Euan Stephen, Baker Hughes: The Mastiff RIS was used in the North Sea from June 2015 to March 2016 to enable an operator to save valuable time in a platform removal operation. The operator faced time constraints as a heavy lift barge was scheduled to remove the platform. The Baker Hughes solution allowed simultaneous operations to progress on the platform on both the RIS and the platform drilling derrick, enabling all abandonment work to be completed within the required time.

Rod Smith, SLB: Making the abandonment process more lean is key in reducing costs without comprising barrier integrity—and in many cases will improve verification success with less risk and HSE exposure.

LIVE digital slickline services have been used extensively in the North Sea and Gulf of Mexico for well abandonment. In some cases, the service is used only for well preparation, plug setting, and tubing cutting and punching. In other applications, it has been used for full abandonment, saving numerous trips for correlations and adding certainty to plug tagging. In the North Sea, the service was used for plug and lubricate operations as part of a well abandonment scope that saved the customer 24 hours per well.

ROAM is engineered and being built at the OneSubsea manufacturing facilities. The system is leveraging existing in-house technologies such as BOPs from Cameron, a Schlumberger company, and workover controls technologies from OneSubsea, packaged into a fit-for-purpose solution. Available later in the year, ROAM will complement existing intervention riser systems (IRS) and subsea intervention lubricators (SIL), expanding applications by enabling completions recovery in open water with environmental control and full well isolation capability without the need for a riser to surface—saving considerable running time.

Delaney Olstad, Weatherford: Our pulling and jacking units have been in operation for a decade, primarily in the Gulf of Mexico. They have also been deployed in the Asia Pacific market. The modular design of the system allows for rapid mobilization and efficient assemblage on the platform. Once on location, an innovative self-clamping skidding assembly enables movement from well to well without the need to rig down any main system components. The numerous capabilities of the PJU also allow it to conduct the majority of operations without assistance from the platform crane, facilitating simultaneous operations. By reducing the time spent on setup and well-to-well relocation, in addition to the minimal need for crane support, the PJU saves time and money.

Baker Hughes’ Retriever jacking unit system. Photo from Baker Hughes.

OE: If you haven’t seen your system used commercially yet, how would it benefit the operator?

Euan Stephen, Baker Hughes: Using a specially designed Retriever JUS for a tubing, casing and conductor removal operation in the southern North Sea from February to April 2017 eliminated the requirement for mobilizing a jackup. This resulted in cost savings of approximately £20 million (US$25 million) to the operator since mobilizing a rig would have required removing a considerable amount of subsea pipe work.

OE: Please tell us the benefits of using this technology. i.e. where are the best instances for using this technique?

Euan Stephen, Baker Hughes: The main benefit of using rigless intervention systems is that mobilization of a jackup rig or full-size platform rig can be avoided, providing significant cost savings to the operator. The biggest benefit of the Baker Hughes rigless abandonment offerings is flexibility. Having two units with different designs means the ability to install units on a variety of platform sizes while providing a cost-effective solution. The unit can be supplied in a basic, lighter-weight version and can also be supplied with additional enhancements to deliver options such as drillpipe racking, well control, surface rotation and integration of services from other product lines.

Rigless intervention systems are used for platform applications. It is important that the platform can accommodate the size of the respective unit and handle the combined load of RIS unit weight + maximum pulling capacity, as this will be transferred to the platform substructure. It is not water depth, but the size of the platform, load capability and occasionally bed space, that determine whether RIS is a good option.

Rod Smith, SLB: As the industry looks to address the abandonment process in its entirety, there will probably be an application for using these Schlumberger technologies in most scenarios. The key benefit of simplifying equipment spreads with more intervention-enabled deployment methods is in reducing reliance on costly and complex drilling rigs while reducing the support costs for operations. High-cost applications such as subsea wells and complex abandonment environments will realize the greatest cost, risk, and efficiency benefits.

Delaney Olstad, Weatherford: As efficiency and profitability become increasingly important throughout the industry, the need for cost-effective, compliant abandonment and intervention resources is critical. Our innovative Rig-Free PJU has demonstrated its ability to improve efficiencies and limit the expense of abandonment and intervention operations.

The primary innovation and benefit of the Rig-Free pulling and jacking unit is in the name—it eliminates the need to employ costly jackup and workover rigs for offshore abandonment and intervention campaigns. For well abandonment or intervention operations involving multiple wells, the elimination of a rig can represent tens of millions of dollars in savings.

With the ability to improve the efficiency for both plug-and-abandonment and late-stage intervention, the Rig-Free PJU has already changed the well economics for many of our customers by increasing operational efficiencies and reducing overall operating costs.