DRILLING & PRODUCTION

Leonard LeBlanc Houston This semisubmersible production vessel designed by Aker Engineering. This downhole and water separator uses a hydrocyclone to separate production and injects the water into a disposable zone. A downhole oil and water separation system developed by a Canadian group headed by C-FER and Paradigm Engineering. The unit incorporates the hydrocyclone developed by Vortoil Separation (Houston) and a dual stream submersible pump developed by Reda Services of Calgary.

Leonard LeBlanc
Houston

Downhole separator uses hydrocyclone, zone discharge

A downhole oil and water separation system developed by a Canadian group headed by C-FER and Paradigm Engineering. The unit incorporates the hydrocyclone developed by Vortoil Separation (Houston) and a dual stream submersible pump developed by Reda Services of Calgary.

The assembly uses two pumps - one to pump the emulsion into the hydrocyclone and the other to pump the concentrated oil to the surface. The hydrocyclone separates the water from the oil and moves the water into a discharge zone accessible from the same wellbore.

Field tests of the system began last year and initial results show an order of magnitude reduction in produced water with no reduction in oil flow. Actual applications of the technology are scheduled for the North Sea later this year.

Oman-India pipeline will transport gas at half LNG price

An indicator of how natural gas will be transported in the future was revealed by studies preceding the decision to build the Oman-to-India pipeline under the Arabian Sea. The cost of landing gas in India using liquefied natural gas was twice as expensive as moving the gas through an undersea pipeline.

The pipeline from Oman to India will be installed in 11,000 ft depths, more than three times as deep as the deepest existing line. The higher cost of installing two heavy wall 24-in. pipelines, with relatively higher costs than presently experienced, cannot match the cost of LNG movement. That information was provided during a topical presentation at the 1995 Offshore Technology Conference.

Surface controlled stabilizer allows drillstring rotation

A telemetry-regulated stabilizer control system developed by Halliburton allows changes in blade diameter to control inclination in deviated wells while the drillstring is being rotated. The development is crucial to eliminating drillstring drips to change the bottom hole assembly when drilling holes requiring many changes in directional settings.

Also, allowing the drillstring to rotate in deviated holes prevents problems such as stuck drillpipe and drill cuttings dropout. Prior to this development, highly deviated holes, extended reach wells, and many horizontal holes requires the use of non-rotating technologies such as coiled tubing. The commands are send by mud pulse sequencing. Return pulses indicate the stabilizer blade diameter.

Fewer offshore people present additional payback to Shell Expro

One of the main factors expected to drop Shell Expro's unit operating costs in the North Sea is offshore manning, explained Dr. Chris Fay, chairman and CEO of Shell UK. But Shell found that in reducing manning, it created other dividends.

In 1992, Shell Expro had staffs aboard 13 of 17 platforms in the southern gas basin of the North Sea. By 1996, the total number of platforms will have increased to 22, but only three of the 22 will be manned. New and old platforms will be converted to unmanned operation.

But a cut in manpower also changed the culture on offshore platforms, he pointed out in a presentation at the 1995 Offshore Technology Conference. Early changes are resulting in better safety and environmental stands. Also, "smaller, better organized and more motivated offshore crews are less likely to suffer from poor communications, which are at the root of most accidents."

Reconfigured semi design for Njord

The semisubmersible production system design selected by Norsk Hydro for the Njord Field off Norway contains a number of alterations from standard design in order to raise capacity while lowering costs:

  • Fore and aft pontoons: Instead of port and starboard pontoons, fore and aft pontoons allow riser connections on the pontoon below the process for many risers or direct hang-off from the process deck.

  • Box pontoons: The pontoons are box-like instead of rounded, a situation that lowers fabrication costs and increases the natural heave of the vessel.

  • Mating boxes: Boxes were developed at the top of the columns in order to allow the running of utility systems prior to deck mating. This reduces the connection time afterward.

The $500 million design, engineering, and construction contract was won by Aker Engineering, which developed its own P-45 design by modifying a GVA 5000 unit to perform production functions. The 45,000 tons displacement will be moored in 350 meters water depth and be capable of producing 70,000 b/d oil and 350 MMcf/d gas.

More in Home