R&D-focused companies have raced to develop remote technology that will cut rig time while maintaining health & safety standards. Red Spider's Rod Falconer discusses how its technology has enabled operators to approach interventions and completions in a new way by cutting necessary rig time through reducing slickline runs and removing the requirement to rig up pressure control equipment altogether.
When the price of oil began its most recent decline, some North Sea operators began looking for new ways to significantly reduce recovery costs and associated risks in carrying out intervention work. One of Red Spider's solutions is eRED, or Electronic Remote Equalisation Device. It is a downhole computer-controlled valve that can be opened and closed multiple times by remote control, without the need for intervention, saving time and money and removing risk. The evolution of eRED technology has quickly gathered pace and taken on a life of its own.
Deployed for remote well control operations in 12 fields in the North Sea, the eRED's electronics and bespoke software allow it to be programmed to repeatedly open and close for intervention and completion procedures without physical intervention, while including safety contingency triggers.
Pressure-activated tools are most commonly operated with differential pressure, meaning their reliability requires on operators being certain of well pressure and other parameters. Since accurate downhole conditions are not always known, Red Spider designed eRED to self-zero itself when run in-hole; it is operated with applied pressure, time or a combination of both. This assures accuracy and reliability regardless of the well pressure below. Triggers such as pressure time window, temperature, hydrostatic pressure, timer or a combination can be programmed into the tool for a single operation, which makes it flexible.
The eRED is programmed before deployment, making it user-friendly, and it can incorporate contingency triggers, which enhances functionality. These triggers can be built in to allow the operator to mitigate the effects of unforeseen or fluctuating well conditions. This has benefits over keeping track of pressure cycle devices with limited number of actuations.
The eRED also has a built-in data acquisition capability for recording a pressure and temperature log downhole, which has proved valuable to operators who have run the tool in combination with third-party memory gauges.
Red Spider has used eRED in several platform operations for BP in the UK and Norwegian sectors of the North Sea. BP first used the product subsea on the Foinaven W17 central water injection well. The slickline runs and rigging up of pressure control equipment eliminated from this operation resulted in a minimum saving of 12 hours of rig time and a significant reduction in HS&E exposure. The BP-operated Foinaven field is 190km west of the Shetland Islands in UK blocks 204/19 and 204/24a. W17 is a central water injection well supporting two peripheral producers.
Programmable electronics and sensors enable the eRED to open and close in response to predetermined pressure and time signals. For the Foinaven run, it was activated using applied tubing pressure over a given time sequence, providing a flexible downhole barrier.
Traditionally, when subsea completions are landed, wireline set plugs and prongs are used as the tubing hanger barrier. This involves several interventions and the use of surface pressure control equipment to firstly install, test and then equalize and retrieve the barrier.
In the Foinaven operation, an eRED replaced the traditional hanger plug, primarily to improve safety, remove risk and reduce time, leading to net cost savings. First, the eRED was made up below a standard 4.875in lock; this was then set into the hanger nipple profile. At this stage, the equalizing ball mechanism was in the closed position, allowing full pressure testing against the barrier to be carried out from above and below. On successful completion of testing, the hanger sub-assembly was shipped offshore.
Offshore, a laptop was connected to the eRED, and diagnostic checks were made to ensure the eRED was operating correctly. The eRED was then commanded to move the equalizing ball into the fully open position. The eRED was run in the open position, allowing fluid bypass whilst landing the tubing hanger. This also allowed pressure to access the lower completion for well control, packer setting, etc.
With the completion at depth, the tubing hanger was landed and locked in place. The production packer was hydraulically set, and the tubing string tested through the open eRED. After successful function, pressure and in-flow testing of the TRSSSV (tubing retrievable subsea safety valve), the eRED was commanded to close, with a pre-programmed pressure and time signature of 2500psi applied to tubing for 10 minutes. A delay of five minutes allowed for bleeding-off pressure before the ball closed.
The closed eRED provided a fully testable barrier, allowing for the drilling BOP to be nippled down and the subsea tree to be installed and tested. Still without any form of intervention, the eRED was then opened remotely with a pre-determined command trigger of 1500psi for 10 minutes. A tubing pressure drop observed at the surface gave positive feedback that the eRED had opened. With the eRED equalized and well pressure being monitored, the hanger plug and lock was retrieved using wireline but without the requirement for full surface pressure control equipment.
The eRED functioned as designed, enabling BP to remotely close and perform multiple tests against the barrier. On command, they equalized across the plugging assembly without the need for a Red Spider engineer to be on location.
In total, the elimination of three wireline runs and the rigging up of surface pressure control equipment resulted in a minimum rig time saving of 12 hours. In addition, using eRED reduced persons on board requirements, cut slickline service costs and reduced exposure to potential waiting on weather time to rig up slickline and general risks associated with interventions.
Subsequent subsea applications have saved up to 24 hours of rig time, and between initial de-completion stage and following re-completion stages, the use of the Red Spider technology provided a total saving of at least 36 hours on one subsea well.
The patented technology was significantly enhanced when parallel triggers were added to the programming capability of the tool to allow for contingencies; it can be used to deliver a repeatable series of commands in a loop sequence. These improvements helped accelerate take-up from North Sea clients. eRED achieved V1 test qualification in accordance with ISO14310 standard in April.
Red Spider is evolving its eRED technology into a product line of remote open close technology tools. New products include eMotion with Revolver (a tubing mounted version of eRED) and PowerBall (a formation isolation valve). Field trials for both these products are anticipated to begin 3Q 2010.
eRED is suitable for deepwater and subsea applications, where the rig time savings are most valuable, so there is potential locally in the North Sea, and internationally in the Gulf of Mexico and offshore Brazil, West Africa and the Asia Pacific region.
With regular savings of over $310,000 savings per job and each operator carrying out multiple jobs for each well intervention/completion, the potential financial benefits to the market is obvious. OE
About the Author
Rod Falconer has been with Red Spider for two years and is the company's technology center manager. With experience in design engineering, operations and completion design, he worked for major and smaller service companies for over 26 years in the UK and internationally.
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