This paper presents an overview of the benefits of the use of synthetic rope winches as a direct replacement to wire-rope winches in ultra-deepwater applications. The Perdido was the first SPAR to use Direct Vertical Access (DVA) to access 22 planned well slots. The planning process invoked many new ideas on technologies required to operate in this ultra-deepwater environment. One of the many innovations that came out of this development was the need to develop a winch that could set Tubing Hangers and X-trees from the actual structure. Prior to the development of the Soft Rope Traction Winch, a wire rope winch was used to perform these tasks. Because of the weight of the wire rope in deeper applications, the actual winch pulling capacity was significantly reduced. The only other method available required utilizing a Multi-Service Vessel (MSV) that could accommodate the size of the winch to perform this two-step process. This approach was expensive and relied on Mother Nature's cooperation which was unpredictable at best. The development of the SRTW provided a viable option to using a MSV. By replacing wire-rope with synthetic rope the winch weight and size would be significantly reduced. The SRTW's small footprint and weight allowed it to be positioned on a cantilevered platform that did not use any of the deck space which is typically at a premium on these structures. The challenge was how to spool soft rope at these depths and not have the weight of the payload work its way between the spooled layers of rope when in tension. Additionally, the characteristic of synthetic rope when placed in various tensions causes deformation and stretching resulting in slippage of the rope during spooling operations. This slippage results in heat being generated due to friction which will ultimately damage the rope. All these challenges were over-come and the winch has proven to be a safe, reliable and economic substitute for wire-rope winches.
This paper presents an overview of the benefits that can be achieved by replacing wire-rope winches for synthetic rope winches in deep and ultra-deepwater applications.
As demand for energy continues to increase, the search for vital energy resources is expanding further offshore into harsher and deeper waters. Globally, there are more than 150 major deep and ultra-deep water developments that have the potential to come on-stream over the next 5 to 10 years (figure 1). This growth is centering upon the ‘Deepwater Triangle’ of Brazil, West Africa and the North American Gulf of Mexico.
