Developing the Future of Gravity Deployed Well Intervention Conveyance

At present there are significant strength to weight ratio challenges in the extreme well intervention market when regarding Extended Reach Drilling (ERD) wells. Conventional cable construction, even when jacketed, restricts either the total depth achievable or the size of toolstring conveyed due to the overpull available when considering the safe working load of the cable. We consider a fundamentally new conveyance construction that can operate both within and on existing well intervention infrastructure to address this challenge. Our approach is to ensure the cables desired strength to weight ratio can be achieved whilst considering its fundamental properties including flexibility and fatigue life as well the suitability of its strength member for the application and environment. In order to achieve this static, dynamic and environmental testing has been conducted. In addition, to ensure integrity is maintained, rapid gas decompression and internal fluid migration are to be considered and tested. As a result of the strict design envelope (which mandated a step change in strength-to-weight ratio whilst maintaining standard well intervention equipment deployment) the future of well intervention conveyance is now up to 75% lighter than the equivalent dimensioned steel cable due to the use of high specification composite materials. Notable challenges in bending radius, fatigue life, fluid migration and surface handling needs were overcome through a variety of unique proprietary approaches. A 0.25" cable with 8200lbs breaking strength can now weigh only 13lbs per 1000ft when submerged in water, and comparative performance against existing cable technology for gas well deployments is even more notable. The future of well intervention conveyance, especially for ERD wells and unconventional applications, lies within high specification composite materials. The practicing engineer will see how new well intervention conveyance can open up previously unreachable depths in the wellbore, and how a step change in strength-to-weight ratio improves operational performance by affording more overpull capacity. Whether the technology is applied to conveying heavier tool string in convention wells, or reaching greater depths in complex ERD wells, the use of composite wireline conveyance compared to traditional steel cable technology is clearly presented for the practicing engineer.