Vol. 59 No. 5

May 2007

Dennis Denney, JPT Technology Editor

Hydraulically Expanded Liner Hanger

Read Well Services uses its Hydraulically Expandable Tubular System, HETS, for expansion of concentric-downhole tubulars by use of direct hydraulic pressure. In January 2007, this technology was used to expand a liner hanger in a well that was drilled directionally with casing in the Norwegian sector of the North Sea. This hanger-packer assembly was able to withstand 20 days as part of the drilling string and then be expanded and set with a load capacity of more than 441,000 lbf and a 5,000-psi gas-tight seal. The twin-wellhead design required drilling with casing to a measured depth of more than 12,000 ft with up to 70° deviation, then conversion of 7 3/4-in. casing-drilling string to a liner. The liner hanger/packer assembly (Fig. 1) was set at 5,000 ft in the 10 3/4‑in. parent casing. With the drill bit at a depth of approximately 7,000 ft, the liner hanger was installed as part of the drilling string. The string then drilled ahead to the 7 3/4-in. shoe depth at 12,000 ft. The casing shoe was cemented, and the expansion tool then was run into the well on drillpipe and engaged in the liner hanger with an integral-latch device. The system was activated and, by generating 21,500 psi hydraulic pressure (above hydrostatic), expanded the diameter of the 11‑ft‑long hanger by 15%, thus “setting” it in the 10 3/4-in. parent casing. The water-based hydraulic fluid for the expansion was carried in a reservoir in the drillpipe immediately above the expansion tool.

Fig. 1—Read Well Services’ HETS downhole expansion by use of direct hydraulic pressure.

For additional information, visit www.readgroup.com/hets.

Fig. 2—Centek Ltd. CT
close-tolerance centralizer.

Close Tolerance Centralizer

Centek Ltd. has introduced its CT centralizer for close-tolerance operations in the Gulf of Mexico. The centralizer has a flexible single-piece construction—integral end-band and spring bow—combined with low-friction and low-drag design. A characteristic of deepwater wells is reduced tolerances as operators run casing through an existing casing, and the centralizer must be flexible enough to compress fully to pass through the close restriction then expand fully back to gauge when it moves into the open hole. The centralizer has been successfully tested over a 6-month period in the Gulf of Mexico. Because of the close tolerances, the centralizer does not use conventional steel stop collars on the outside of the liner casing; instead, the end-bands are notched, allowing low-friction composite limiting blocks to be inserted (Fig. 2), thereby ensuring that the centralizer is pulled into the well rather than pushed. As a result, drag is reduced. This centralizer can pass through clearances as small as 2.5 mm. The centralizer uses Protech Centerform’s carbon-fiber/ceramic composite material for the limiting blocks, which are molded directly to the casing to form a permanent stop that will not slip.

For additional information, visit www.centekltd.com

Cleaning and Corrosion-Inhibitor Treatment

Nalco Company introduced its Clean N Cor technology, a cleaning and corrosion-inhibitor-treatment program designed to protect piping and maximize production from oil fields having oil-sludge deposition challenges. Sludge deposits on the inside of pipelines can cause injection restraints in produced-water injection systems and increased localized corrosion. This program uses chemistry and in-field monitoring to aid removing sludge deposits from the inner pipe walls and filter equipment and then prevent aggressive corrosion from taking place. This patented multifunctional chemistry was developed through an intensive research effort and then field proven in a series of aggressive trials. The program removed 99% of the oilfield sludge from dirty production equipment in less time than conventional inhibitors required to remove 30% of the sludge buildup. In an example water-injection system, this sludge-removal program resulted in 75% greater water injection. Once the sludge was removed, the system prevented the sludge from readsorbing. The technology then protected the pipe surface by providing a persistent film that acted as a barrier to corrosive fluids.

For additional information, visit www.nalco.com

Fig. 3—Smithlift Hydraulic-
Diaphragm ESP system.

Dewatering CBM Wells

Smithlift has introduced its artificial lift technology to dewater coalbed methane (CBM) wells. A primary operational goal is that of maximizing gas rates while minimizing the amount of associated water in the wellbore. It is common for some wells to produce more than 600 BWPD initially and then fall to less than 100 BWPD within 12 months. Conventional electrical submersible pumps (ESPs) have been used widely to dewater CBM wells, especially during the initial production period when the water rates are high. After this period, conventional ESPs are less effective at the lower water rates and/or when the well produces solids such as coal fines and sand. A conventional centrifugal pump uses rotating impellers in fixed diffusers. These impellers have small vane openings that tend to plug with solids at low flow rates and cause the pump to fail. The new Hydraulic-Diaphragm ESP system (Fig. 3) overcomes limitations of the conventional ESP. The positive-displacement double-acting diaphragm pump, driven by a downhole electric motor, has been used to produce low-liquid-rate wells (less than 200 BPD). The diaphragm provides a positive seal that isolates the pumping mechanism from abrasive solids and coal fines that can plug a conventional ESP. The new pump also can be used to produce low-volume stripper-oil wells. The pump has documented power savings greater than 50% when compared to alternative systems. The pump requires no routine on-site maintenance, and current field installations are generating run lives of more than 1 year.

For additional information, visit www.smithlift.com.

Coiled-Tubing Logging Head

AnTech Ltd. has introduced its coiled-tubing (CT) Logging Head (Fig. 4). The device uses a remotely operated emergency electrical disconnect that makes it possible to carry out a controlled release from the CT. CT operations often include running electric-logging tools. These operations require an electrical cable to be run inside the CT. This new device provides a safe and secure means of connecting the logging tools to the CT and the electric line. The new electrical release eliminates the possibility of shock or pressure spikes activating the release. The electrical disconnect is controlled and fail-safe. The weakest point of the CT string is at the top of the well, but the disconnect device repositions the weak point just below the CT. The electrical disconnect works by applying a sustained flow of current—in this case for approximately 2 minutes—to activate the release, leaving a fishing neck exposed at the top of the remaining tool.  It will not inadvertently activate as a result of pressure or shock because it is not a weak point until the electric current is activated. A protective circuit that requires a sustained reverse current is built into the electrical release to prevent activation by operating other electrical tools in the string.

Fig. 4—AnTech Ltd.’s CT Logging Head.

For additional information, visit www.antech.co.uk

Fig. 5—The Schlumberger Reda
Maximus ESP system.

Maximizing ESP Operation

Innovative engineering has minimized ESP failures cause by human error or climatic conditions and improved reliability. The Schlumberger Reda Maximus ESP system (Fig. 5) is designed for the motor, protector, and sensor to be a fully integrated (plug-and-play) system. The system arrives at the wellsite ready to install with fewer mechanical connections and no oil servicing. The only connections in the fully integrated system are the plug-in electrical connection and the connection of the intake to the top of the protector. For flexibility or high-horsepower applications up to 1125 hp, the system comes with plug-and-play components prefilled with oil in the controlled environment of the manufacturing or service center. These components are transported to the location with an oil compensation-shipping cap such that no oil servicing is required at the wellsite. This method allows for the motor and protector to be filled with the correct oil for the hotter downhole conditions independent of the surface conditions. In addition, this method reduces the risk of oil contamination cause by rain or high humidity, blowing sand or dust, or other climatic conditions. The new ESP can reduce the time needed for wellsite assembly. With the number of wellsite tasks decreased, an operator can release a rig and start producing a well sooner than with a conventional ESP.

For additional information, visit www.slb.com/redamaximus.

Field-Installed Rod Guides

The Stealth XL high-performance field-installed rod guide from R&M Energy Systems (Fig. 6) is designed for difficult downhole conditions. Deep concave channels and the streamlined shape give the rod guide excellent flow characteristics in high-volume wells. Wide vanes provide increased bearing surface area for wear protection on rods, rod couplings, and tubing in deviated wells. Proprietary reinforced-carbon material provides superior holding power and a 400°F temperature rating for rugged well conditions. The field-installed rod guide eliminates the need to remove rods from the wellsite for rod-guide installation. The wide vanes provide maximum footprint or surface-bearing area. Distributing the load across the wider vanes results in improved downhole wear protection and longer service life. The concave body also improves structural integrity for shock and impact resistance. The 7-in.-long rod guides provide durability and wear distribution needed for horizontal applications, highly deviated wells, or other severe wear applications.

Fig. 6—The R&M Energy Systems Stealth XL high-performance rod guide.

For additional information, email info@rmenergy.com.

Revolutionary Rescue Device

A new offshore-rescue device, launched by Reflex Marine, the Rob Reid Rescue Device (Fig. 7) can cut vital minutes off a rescue operation and is simple to deploy. The rescue device can be deployed from support vessels and floating production, storage, and offloading vessels. Weighing only 71 lbm for the one/two-man cage and 89 lbm for the two/three-man version, the rescue device can be deployed in 20 seconds. Once in the water, it floats with an aluminum diamond-grill base approximately 12 in. below the surface, providing a safe haven with easy entry. The horizontal recovery position then reduces the risk of the casualty going into shock while being lifted back on board. The speed of deployment and recovery may eliminate the need to launch a rescue craft.

Fig. 7—The Reflex Marine Rob Reid Rescue Device.

For additional information, visit www.reflexmarine.com.