Well integrity matters

Richard Craig Nov 7, 2013

Meta has deployed its Metalmorphology technology in wells in the North Sea and Gulf of Mexico. Richard Craig explains.

Well integrity, particularly the structural and casing integrity of wells, is a key issue in the offshore oil and gas sector. Certain parts of the world, such as the Far East, are still experiencing “light touch” regulation. The same cannot be said for operators and drilling contractors in other regions, such as the Gulf and Mexico and the North Sea.

Legislation that applies pressure on operators to establish well integrity and contingencies at the planning stage of all their wells includes the US Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE), whose duties have now been taken over by the Bureau of Safety & Environmental Enforcement, the UK’s Health & Safety Executive (HSE), and Norway’s Petroleum Safety Authority (PSA). It is not just regulators pushing for well integrity. For operators, highquality well architecture and strong structural and casing integrity are vital platforms for the future success and profitability of a well.

Strong casing and structural integrity will allow lifecycle asset teams to drill deeper and reach total depth without delay and or deviations from drilling plans and the accompanying costs. It can also help avoid operational setbacks through issues such as stuck or damaged casing, and pre-empt other well architecture weaknesses that can come back to haunt operators during the completion and production phases.

There are many well integrity technologies on the market today. However, more needs to be done to establish structural and casing integrity at the outset, plan for well integrity across the well lifecycle, and overcome existing technology weaknesses.

Metalmorphology has been developed to use established metal-working principles to shape metal downhole with control and precision to deliver a gas tight and durable metal-to-metal seal. The technology balances the mechanical strength of steel with its elastic properties to create isolation solutions that instantly morph together to provide 100% conformance with the wellbore or casing. Metalmorphology provides a “morphing” ratio up to 60%, an axial load bearing rating up to 6 million lbs and a sealing rating of up to 15,000 psi. The result is a gas-tight, axial load bearing, metal-to-metal sealing solution, which meets well integrity legislation.

Addressing stuck casing challenges in the North Sea

Meta has adopted its Metalmorphology technology to a number of well integrity solutions.

One, Meta Casing Reconnect, tackles damaged or stuck casing by enabling operators to cut the original stuck or damaged casing at the required point, and deploy the reconnect solution over the existing casing, and reconnecting it to new casing with a connection capable of withstanding over 1,000,000 lbs of axial loading, and providing a metal-to-metal V0 gas-tight seal.

It has been used in the southern North Sea, where an operator was faced with a 9 5/8-in. leaking casing string and had lost significant rig time attempting to regain integrity, with the use of swellable technology being unsuccessful. Costs of the project were escalating and a solution had to be implemented within a small operating window to ensure integrity was regained.

Meta’s Metalmorphology-based reconnection system was deployed and resulted in the placement of a metal-tometal connection of the existing 9 5/8-in. casing string to the surface. The operation allowed the operator to continue with their well plan without the need for intervention work and the pulling of the casing, leading to cost savings of nearly US$4 million. The well now has a reinstated life of well gas tight seal qualified to more than 5000 psi and a casing capable of carrying more than 600,000 lbs in tension and compression.

Meeting Regulatory Demands in the Gulf of Mexico

In the Gulf of Mexico BOEMRE/BSEE requests additional information on well planning activities in the form of a new worst-case discharge criteria, particularly applicable in deepwater wells. All assumptions made regarding well design, estimated flow rates, the maximum duration of potential uncontrolled flow and the total volume must all be considered.

This has made it necessary for operators to alter their well designs and strengthen well architectures—particularly at the earlier well lifecycle stage—to adhere to these regulations.

While there are a number of liner tieback solutions on the market, many are dependent on elastomeric elements. Elastomers come with a number of reliability issues relating to their sealing capabilities and duration and potential internal diameter (ID) reductions.

Meta has developed a liner tieback solution to enable operators to demonstrate and often exceed legislative compliance.

Through morphing the tieback casing into the Meta tieback receptacle, an ISO 14310 VO gas tight certified metal-tometal connection is established with no reliance on elastomers. The durability of the metal-to-metal seal enables it to operate at pressures of up to 30,000 psi, and temperatures of more than 160°C. An axial load capacity of 1,700,000 lbs makes it suitable for deepwater environments, such as the Gulf of Mexico, with the axial loading bearing capabilities allowing for deeper drilling.

Additional benefits are reduced rig time for the landing and spacing out of the casing string.

A series of Meta tieback systems are due to be installed by Shell in a deepwater Gulf of Mexico field. The operating temperature will be 120°C and, once the tieback is installed, the deployment depth 10,000 ft. Hydrostatic pressure at this depth will be 3750-5800 psi, depending on fluid in the well.

Through the incorporation of the liner tieback into its well architecture, Shell will ensure the well architecture remains fully compliant with current regulations; overcomes limited IDs in casing strings to achieve high load-bearing capabilities; allows asset teams to plan for drilling deeper; and provides flexibility of space out.

Redefining well integrity

These examples focus on structural and casing integrity. Metalmorphology is also playing a role further along the well lifecycle, allowing for the proactive planning of zonal and barrier integrity as well as restoring well integrity and enabling operators to isolate selected zones during production.

Metalmorphology is proving how well integrity can be planned and how preexisting technology limitations can be overcome, reducing risk, protecting and maximizing future production. OE

Richard Craig, vice president of business development at Meta, has 25 years’ experience in the offshore and onshore oil and gas sector, primarily within the drilling sector. Previous roles include business development manager at Enventure International and technical sales director at Global Drilling Supplies. He also spent 16 years at Noble Drilling.