Expandable open hole liner

Statoil ASA has completed the application of solid expandable tubular (SET) technology in a high-angle well in the Gullfaks field.

Frank Hartley • Houston

Expandable open hole liner

Statoil ASA has completed the application of solid expandable tubular (SET) technology in a high-angle well in the Gullfaks field. Statoil used Enventure Global Technology's 11 3/4 by 13 3/8 in. open hole liner (OHL) system to isolate a high-pressure zone and maintain vital hole size in directional well in the Norwegian North Sea.

Enventure, working as Halliburton AS in Norway, assembled an expandable program for Statoil's C-43 T2 oil well that consisted of the 11-in. inside diameter OHL system expanded to 12 1/4-in. outside diameter in the openhole at an angle of 77°. According to Enventure, the technology has considerable potential for similar applications for sealing off depleted or high-pressure zones within the reservoir interval without losing hole size.

The application marked the first time an SET system of this size was installed in a well of such high angle. After sealing off the zone, the 222-m SET system enabled Statoil to reduce the mud weight, drill through the lower pressure zones, and reach TD with a viable hole size. The significance of this installation lies in the ability to seal off the high-pressure zone in a severe angle and to successfully deploy the system in a high-angle directional well.

The high-pressure zone in the Gullfaks field historically causes time consuming and costly drilling problems. By implementing this solution, Enventure says, more well construction challenges can be averted in adjacent wells without compromising completion options.

Chemical water shut-off

A new materials technology, developed specifically for the oil and gas industry, was used in what is thought to be the world's first chemical water shut-off in a horizontal annular well section. Shell UK, BP, and Talisman Energy (UK) Ltd. have used Thermatek, a temperature activated rigid setting fluid, in North Sea interventions, and the operators are reported to have been impressed with the results.

The fluid can be used in a number of near wellbore applications, including lost circulation, well abandonment, and water/gas zonal isolations. Deepearth Solutions Ltd. developed and owns the fluid technology, and PSL Energy Services Ltd. has the rights of supply for the UK, Norway, and Denmark.

In November 2002, Shell UK was the first operator to use the fluid for isolating a watered out horizontal well tubing and casing annulus section. Placement of the setting fluid was by conventional coiled tubing operation. The intervention was successful and is believed to be a world first for a chemical shut-off in a horizontal casing annulus. BP has since repeated use of the fluid, with PSL Energy Services providing the full package of chemicals, blending equipment, and coiled tubing services.

Following the initial success, Shell UK is in the middle of a four-well campaign to repeat their first horizontal well water shut-off. Two wells were completed with total isolation achieved and a similar level of success is anticipated for the two wells to come.

In many water-driven reservoirs, it is common over time for the oil rim to "float" on top of the injected water and move up-hole to the point where the horizontal well section is located in the water zone and produces only water. At this point, it is desirable to isolate the horizontal well section and re-perforate higher up the well into the oil zone. Historically, it has proven extremely difficult to achieve any level of success with chemical products or cements in a horizontal well section due to the "slumping" effect of the fluid or slurry during an extended set time.

The setting fluid was used in the Andrew A07/04 to shut off all existing perforations. The shut-off was completed in the horizontal section of the well consisting of a Baker inflatable permanent plug and setting fluid. The placement was dictated by completion restrictions and injectivity rates. The plug was set below the present upper perforated interval. A volume of setting fluid was then placed above the plug with coiled tubing and immediately followed by gel with squeeze pressure applied to force the fluid into the perforation tunnels.

After placement, a mill assembly was run to tag the top of the setting fluid and to mill out any excess. Negligible milling was required to remove it from the tubing with the top of the plug found within 1 m of designed depth. The knowledge gained during the operation was instrumental as more shut-offs are planned in the years ahead for Andrew and other BP fields.

Monitoring and optimization

The rapidly growing oilfield interest for remote data acquisition, real-time data integration, and production monitoring and optimization has led to the joining of vMonitor Inc. and Baker Hughes Inc. This union will enable the business units, such as Centrilift, Baker Petro-lite, and QuantX (a joint venture between Baker Hughes and Expro International Group Plc) to deliver combined hardware/software solutions that capture, manage, and integrate remote data to monitor and optimize artificial lift, chemical injection, and permanent in-well monitoring systems.

Founded in 2000, vMonitor integrated systems for remote oilfield operations. Shell Technology Ventures Inc. is an investor, and several Shell business units were early adopters of this technology. The system has been deployed with oil and gas companies in North and South America, the Middle East, and the Asia Pacific region. The system offers advanced technology in remote data acquisition and wireless communication, and it provides Web-based auto- mation software for data acquisition, data management, and integration.

Dopeless connection

The successful running of the 5 1/2-in., 32 ppf, Q125 TenarisBlue Dopeless connection at the ConocoPhillips' Ekofisk X50 well in Norway has been achieved. This is the first time a dopeless connection has been run at an offshore location. The original goals were to carry out a reliable and efficient operation with minimum impact on the environment. The connection was well suited to this objective, with its performance characteristics and the opportunity to eliminate pipe dope from the tubular column, which reduces both operational risks caused by the build-up of dope and contaminants, and environmental risks related to losses of dope to the mud and formation.

The well at Ekofisk was a horizontal well and required a high-performance connection to withstand additional pressure and compression, including being used as a rotating liner. The operations included torque conditions of 25,000 ft-lb, well exceeding the standard value of 18,000 ft-lb make-up torque. The connection reduced time for rig preparation and eliminated costly time-consuming tasks, such as removing storage compounds and applying dope. More importantly, combined with automatic equipment, it eliminated the risk of having personnel on the drill floor to apply dope.

Vibration suppression

The installation of vortex-induced vibration (VIV) suppression fairings for the Modec-built TLP is soon to be completed in the Gulf of Mexico by Shell Global Solutions (US) Inc. At 4,300 ft and located at Green Canyon block 608, the Marco Polo TLP will be the deepest in the GoM.

The fairings were installed on the mooring tendons of the platform and are designed to suppress vibrations caused by water currents, helping to prevent premature fatigue failure. The tendons, with VIV suppression fairings already in place onshore at Kiewit Offshore Services in Ingleside, Texas, will then be shipped offshore for final installation on the Marco Polo TLP.

Retrofitting existing platforms with the patented VIV suppression fairings, using the compact RIVET™ ROV tooling package can expedite the process. Patented suppression fairings offer VIV suppression and low drag loading when compared with conventional helical strakes.

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