DRILLING & PRODUCTION

Mag-Well magnetic fluid conditioners are used for the treatment of calcium carbonate without the need for chemicals. The above shows the effects of this product. The running of this pump is well over 180 days now. The stage is set in Garden Banks Block 260 in the US Gulf of Mexico for the first non-guyed compliant tower used offshore for oil and gas production. The 351 ft tall tower base was installed in the first week of April in anticipation of the tower ship-out in mid-May.

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William Furlow
Houston
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Mag-Well magnetic fluid conditioners are used for the treatment of calcium carbonate without the need for chemicals. The above shows the effects of this product. The running of this pump is well over 180 days now.


Bald Pate tallest world structure

The stage is set in Garden Banks Block 260 in the US Gulf of Mexico for the first non-guyed compliant tower used offshore for oil and gas production. The 351 ft tall tower base was installed in the first week of April in anticipation of the tower ship-out in mid-May.

Once the tower and its topsides are in place, the structure will stand 1,902 ft from the seafloor to the tip of the boom. This will make the Bald Pate tower the tallest man-made structure in the world. The compliant tower technology being applied in this case by Amerada Hess, operator, and 50% partner Orxy, is the latest in a string of low-cost creative options to develop fields that would otherwise not be economically viable.

The compliant structure is lightweight and inexpensive to construct, compared to a conventional platform. The tower has a much higher primary bending natural period, above 30 seconds, compared to less than 6 seconds for a conventional platform. This means the tower will respond more softly to wave forces, deamplifying these forces and converting them into structure inertia. Because it has primary natural periods much greater than those of hurricane force waves, the platform overcomes the problem of dynamic force amplification.

The GB 260 tower is built with eight axial tubes and an articulation point 500 ft above the seafloor. These features govern the dynamic characteristics of the structure. The tubes keep the tower upright and allow it to accommodate operating loads and withstand extreme weather. The tower will have more lateral movement than a conventional platform. It may displace as much as 10 ft during a severe storm. During an extreme event, 100-year recurrence hurricane or loop current, tower displacement at the water line may reach 25 ft.

From an operating standpoint, a significant advantage of the tower is the fact that it can employ an unmodified API rig for well intervention and wells can be tied back and completed utilizing conventional wellheads (15,000 psi well pressure wellhead equipment is required at GB 260). This sets it apart from other low-cost deepwater development solutions.

Mag-Well claims support emerging

Magnetic fluid conditioners (MFC) have often been referred to as black magic or snake oil. Technicians did not accept the"scientific mechanism" behind the principal - fluid conditioning created with a magnetic circuit. Now Mag-Well says the Rogaland Institute and AEA Technology have witnessed, identified, and repeated this"scientific mechanism," but would not publish such findings due to the fact the information is owned by the funding members of the study. Members are major offshore producers.

Mag-Well MFC's are marketed as a Halliburton product, used to treat calcium carbonate without the need for chemicals. The product is used for the treatment of both organic and inorganic scales in flowline and downhole applications.

According to Mag-Well, Brunei Shell Petroleum is using the products to reduce scale and chemical use in its flowlines. Mag-Well has also suspended mechanical remedial work in six onshore Seria Brunei Shell wells that required multiple de-waxing wireline services per year.

Assuming it works, MFC would offer the advantage of a one-time capital expenditure that would reduce or replace the repetitive behavior of chemicals, wireline and thermal treatments. Mag Well/Halliburton MFCs are made of permanent rare earth magnetic materials and do not require external power. The only maintenance necessary in a properly designed MFC will be fluid volume specific, and the flow rates would need to be monitored. Mag Well points out that the successes with Shell are not equivalent to an endorsement of the product, but show this technology is emerging from what the company characterized as a"witch burning" mentality.

Endorsement or not, Mag Well is racking up a list of customers who don't seem intimidated by the mystery surrounding the"scientific mechanism." A current customer list provided by the company lists Shell Malaysia which signed a contract to acquire additional Mag-Well MFCs to complete the retrofit of the St. Joseph Field gas lifted wells located offshore in the South China Sea for the treatment of wax deposits. This contract is the first offshore field-wide commitment to MFC technology anywhere in the world, according to Mag Well.

In the UK, Broken Hills Properties made a MFC purchase commitment, up to 22 units, through Halliburton Aberdeen to retrofit their entire Douglas Field for wax control. The Douglas Field is located offshore in the Irish Sea just south of Liverpool and is completely produced by electrical submersible pumps. This project will ultimately be the largest MFC offshore installation to date. Other contracts are in place with Texaco, Pemex, and TOTAL Australia.

Mag-Well said it is cooperating with the AEA Technology (Atomic Energy Association) of the UK in a recent study, funded by Shell Petroleum and British Petroleum. The study was conducted to witness the affects on a crystal nucleating sight when placed under the influence of a magnetic field. The methodology used was the application of an Atomic Force Microscope, which basically measures surface contours on a molecular level.

For the first time, Mag-Well said the AEA generated output repeated laboratory results of the positive effects of reducing scaling with the use of magnetic forces. Mag-Well and Halliburton will now act as consultants to Shell and AEA for the second phase of this investigation, which will involve the evolution of optimization usage.

Two wells better than one

On the Tukau field offshore Sarawak, Petronas Carigali has designed and constructed a twin well in which two wells are drilled instead of one. While this is by no means the first twin well ever drilled, the Tukua well is unique in that it allows space for three production strings.

The goal is faster depletion of the reservoir at a lower cost. The twin well alone is estimated to save 2%. Petronas Carigali reportedly plans to merge this cutting edge technology with knowledge gained from drilling the first tri-lateral horizontal well on the Bokor field, offshore Sarawak in 1996. This design featured three wells drilled from one trunk to drain separate reservoirs. The combined technology would allow one to drill four wells from a single bore.

The driving forces of faster reservoir depletion and cheaper well construction would make such technology attractive for marginal fields, according to Petronas.

Versatility makes packer economical

Cameron has made an improvement to its ram packers. The next generation VBR-II and Flexpacker-NR feature a Camcurv curvilinear insert that makes them adjustable. This insert forms an iris around the pipe to give uniform sealing pressure and eliminates extrusion paths. The units are tested to API 16A standards and Cameron's Elastometer Technology arm says that it conducted 1,000 cycle closure endurance tests with no fail results for the VBR-II. A new nitrile rubber and modified manufacturing process give the products a longer service life.

Because the new packers are adjustable, it is not necessary to make ram or packer changes for a tapered drillstring or different size drill pipe. Operators can use their existing Cameron BOPs and choose between the Flexpacker, which will fit a certain range of standard pipe sizes, or pay more for the VBR-II that can cover a much wider range of sizes as well as a hexagonal Kelly.

Copyright 1998 Oil & Gas Journal. All Rights Reserved.

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