Interval-Control Valve Meets Deepwater, HP/HT Needs

Abstract

Technology Update As operators push into new, more demanding environments in the search for hydrocarbons, technology providers have stepped up efforts to design downhole equipment to meet the challenges. Nowhere is this scenario more evident than in deepwater settings at depths beyond 7,500 ft, where pressures and temperatures can be extremely high and often render completion equipment ineffective. A durable interval-control valve (ICV), designed especially for deepwater and high-pressure/high-temperature (HP/HT) conditions, has been developed recently by WellDynamics (a Halliburton company) as a key addition to the company's suite of intelligent-completion technologies. A core component of an intelligent-completion system, an ICV enables the control of well inflow or injection downhole, at the reservoir, without physical intervention. Operators, by this means, are able to optimize production and improve recovery (Fig. 1). The inaugural installation of the valve, called the HS-ICV, was recently in progress at the StatoilHydro Snorre B complex and slated for completion while JPT was at the press. Additional installations are planned at the operator's Gøya and Tyrihans assets. StatoilHydro has been closely involved in the design and qualification of the new ICV. A 15,000-psi version of this ICV, designed specifically to meet HP/HT needs in the Gulf of Mexico, is now being developed for a major operator. Currently, valve development is in the prototype stage, with qualification testing slated to conclude by mid-2009. ICV Design and Operation The ICV technology was developed with three goals in mind.Reliable performance in HP/HT conditions, encompassing temperatures up to 330°F and pressures up to 15,000 psiCompatibility with existing downhole-control and incremental-positioning systemsEnablement of closed-loop reservoir optimization The ICV is actuated hydraulically and operated remotely from the surface by means of downhole-control-system technology. The valve design incorporates optional position sensors that, in conjunction with permanent monitoring systems, provide real-time feedback on the valve position. The ICV also has been designed optimally to allow bypass of multiple hydraulic- or electric-control lines, without compromising the valve rating, and thus enables smooth, reliable ICV installation in complex, multizone applications where there are multiple control lines. Metal-to-Metal Sealing A key design feature of the ICV is a proprietary, debris-tolerant, metal-to-metal seal, which enables the valve to unload at differential pressures of up to 5,000 psi. The sealing system enables life-of-well performance in the most demanding environments and features a secondary thermoplastic wiper/seal, which eliminates the potential for seal damage caused by downhole debris. The sealing arrangement has been rigorously tested and qualified at low and high (15,000-psi) static pressure differentials, providing the basis for developing future, high-pressure versions of the valve.