Blending innovation benefits to drive down intervention costs

By Alistair Geddes, chief operating officer, Expro

The CoilHose Light Well Circulation System (LWCS) available from Expro substitutes the conventional steel coiled tubing with hose
The CoilHose Light Well Circulation System (LWCS) available from Expro substitutes the conventional steel coiled tubing with hose (photo: Expro)

The world demands more energy
Pressure on the oil and gas well infrastructure continues to be challenged by ever increasing global demand. In its World Oil Outlook 2018, OPEC predicts primary energy demand will increase by 33% to 2040, with oil remaining the fuel with the largest share in the energy mix [1].

The intervention challenge
It is therefore important that the industry looks for new and innovative techniques to enhance production from existing wells as it emerges from one of the most challenging economic downturns in its history. With a revitalised focus on expenditure, the industry has been presented with a dual responsibility: to maximise the recovery of hydrocarbons in order to satisfy growing demand requirements, and to do this in the safest and most cost-efficient manner possible. A third challenge is to ensure that once wells have been exhausted of their resources, they are decommissioned or abandoned using the most responsible, safe and efficient methods that comply with legal requirements.

Issues such as well barrier failure and plug and abandonment (P&A) demand efficient solutions. Research gathered by Expro suggests approximately 19% of the world’s gas wells suffer from a degree of leakage while a common location for a well leak (loss of barrier) can typically be found in the annulus between the casing strings.

Potential sources of a well integrity issue can include inadequate cementing; expansion or contraction in the casing; movement of the formation; corrosion; changes to the completion fluid over time; leakages in downhole packers or plugs; and leaks in surface equipment.

The consequences can be severe. From a safety perspective, annulus pressure and casing leaks represent the risk of an uncontrolled release of pressure from the well, which in turn could result in the release of hydrocarbons and other formation fluids.

From a P&A perspective, the underlying drivers for global decommissioning and P&A activity include regulatory or legislation trends towards the implementation of comprehensive legal regulation for the decommissioning and safe abandonment of oil and gas wells, and an increased focus on operational safety offshore. In terms of the P&A market, a low oil price and increased rig availability can shift the emphasis from enhancing late-life production for aging fields and infrastructure to accelerating economic cut off dates. Operationally, there is an increased focus on innovative solutions to reduce time, cost, operational complexity and risk related to P&A.

Developing solutions
With cost reduction a key challenge in the modern industry, attention on the role workovers and interventions can play in safely extending field life or managing abandonment has never been greater. A response to this has been the development of a range of new and innovative technologies and a review of conventional practices and processes to enable production optimisation or P&A at an attractive project lifecycle cost.

Expro has been a leading global provider of intervention services for more than 40 years and recently acquired Norwegian company, Quality Intervention (QI) which added new coiled tubing technology, annular integrity technology and innovative in-situ wellhead remediation tooling to its product and services range. This has enabled Expro to build on its existing P&A offering and expand into a coiled tubing and pumping service market, valued by the company at an estimated USD 6.3 billion.

Integrating advantages
Conventional coiled tubing delivers high rate circulation, but it can be heavy, bulky and time consuming to plan and mobilise. The process can involve potential HSE exposure; significant rig-up and lifting (approximately two to three days); considerable costs (more than USS 1 million); a high number of personnel and a relatively heavy and large footprint. Furthermore, coiled tubing can only be deployed on large rigs or platforms or spooled from a vessel.

The CoilHose Light Well Circulation System (LWCS) rigged up
The CoilHose Light Well Circulation System (LWCS) rigged up (photo: Expro)

The CoilHose Light Well Circulation System (LWCS) available from Expro substitutes the conventional steel coiled tubing with hose. The system enables rigless light circulation services from a package with a relatively small footprint and offers operators an alternative to coiled tubing that can be rapidly deployed across all types of installations both onshore and offshore, reducing overall HSE exposure while maximising operational uptime.

Rig up time for the new system is no more than four hours and the number of personnel required ranges from four to six (compared to up to 11 or even more for coiled tubing). Lifting requirements are limited and it can be deployed almost universally across all types of installations and into the most challenging of wellbores, at temperatures ranging up to 150° C and to depths in excess of 10,000 feet.

The LWCS does not utilise an injector like coiled tubing; instead, it is weighted down by the bottom-hole-assembly (BHA) connected on the downhole end of the hose and run-in-hole by gravity-feed, in a similar way to wireline. The CoilHose unit is used to deploy and retrieve the CoilHose and BHA from the wellbore.

The tubing itself is a coiled and flexible high-pressure hose, reinforced to handle the harsh environment within a well. It incorporates several layers of high tensile steel wires and an outer layer made of thermoplastic materials. With a safety factor of four, the specially designed hose has a working pressure of 12,500 psi.

The pressure control package used to deploy CoilHose into the wellbore consists of a customised pressure control head and triple or quad ram blowout preventer (BOP). The ram configuration is set to be the same as for a coiled tubing operation, with a shear/seal on top and pipe rams in the middle and at the bottom. The pipe ram is designed to seal without damaging the hose.

All BHA components such as the end connector, dual flapper valves, straight pull release, swivel, weight bars, turbine and variations of cleaning nozzles have been designed and manufactured to complement the system and maximise the intervention objectives. Applications include downhole safety valve (DHSV) and wellhead cleanout, nitrogen gas lift or unloading wells, memory logging services, halite and hydrate removal, tubing cleanout and fluid displacement.

This technology provides the further efficiency of being able to deploy wireline from the same unit thus avoiding lengthy and costly idle rig up and down periods between the different types of intervention.

Changing the intervention market, CoilHose delivers a novel, safe and cost effective solution to conventional coiled tubing
Changing the intervention market, CoilHose delivers a novel, safe and cost effective solution to conventional coiled tubing (photo: Expro)

In addition to the intervention of the main wellbore, Expro now has the ability to enter and intervene the annuli. With casing integrity issues such as pressure in the annulus, a growing concern due to the industry’s stock of aging wells, Expro’s annulus intervention solutions are helping to address well integrity challenges.

Applications include downhole circulation in the well annulus, remediation of sustained casing pressure and cementing, annulus fluid replacement, sealant for downhole leak repair, corrosive fluid displacement, diagnostics and logging and environmental and groundwater protection.

The WellSpring annulus intervention system offers minimally intrusive equipment allowing the wellhead remediation of annular integrity issues without the use of a heavy workover rig, resulting in significantly reduced cost (up to 95%). This system, which can be rapidly mobilised, helps operators prolong the life of wells and increase recovery through the revitalisations of shut-in and low production wells.

Proven success
The CoilHose LWCS system has been deployed on multiple occasions with more than 100 runs in live wells. It was used recently to successfully remediate a failed DHSV in a well in the North Sea where scale build-up was suspected to have impeded full travel of the flow tube resulting in the failed test for the valve at 1,740 feet.

Following a thorough assessment and planning process including high pressure pumps and a filter/suction package, a 2,500-foot-long hose was run in the well and a nozzle was used to jet a solution including 15% hydrogen chloride at 3 feet a minute across the valve. Subsequent tests on the DHSV provided positive results for the operation undertaken, with full flow tube travel restored.

Improved intervention
The development of CoilHose is drastically changing the intervention market by delivering a novel, safe and cost effective solution to conventional coiled tubing. It is emblematic of a broader drive towards enhanced and improved intervention innovation in the oil and gas industry, to maximise value from mature wells and ensure their safe abandonment.

[1] OPEC World Oil Outlook 2018

Alistair Geddes, Chief Operating Officer, Expro
Alistair Geddes, Chief Operating Officer, Expro

AlistairGeddes has enjoyed a successful 30-year career in the oil and gas industry, having started his career with BP and held senior management roles at Mobil/ExxonMobil, BG Group and Weatherford International. He joined Expro from Weatherford, where he latterly held the position of Vice President for the Asia Pacific region. Geddes joined Expro in 2011 as President for Strategy, Resource Development & Support, before being appointed to Executive Vice President, responsible for Product Lines, Technology and Business Development in 2014. Most recently, Geddes was appointed to Chief Operating Officer (COO) in 2019, responsible for Region Operations, Group Business Development, Group Subsea Well Access Sales, Group HR and Group HSEQ.