Dual Gradient Drilling is an exciting technology which promises to solve the current
technical hurdles and economic risks of Deepwater Drilling. Several techniques for Dual
Gradient Drilling have been proposed to the industry. One such method involves
installing a subsea booster pump at the seafloor with the aim of returning the drilling
fluid back to the rig. The pump will manage annular pressures in the wellbore as
circulation rates and mud weights vary and will permit early detection of wellbore
influxes. Any such pump chosen to achieve this objective will be subjected to very high
differential pressures and will be faced with the onerous task of lifting very abrasive and
viscous mud slurries from the sea floor back to the drilling rig. This distance in deep
water may be well within the range of about 4, 000 – 12,000 feet depending on the
operating water depth of the rig.
Several pump technologies available to the industry were examined. Piston pumps are
very efficient and can withstand the high differential pressures encountered in the
Mudlift Drilling System. However, their drawbacks are their large size and weight and
high initial capital cost and maintenance costs. Centrifugal pumps on the other hand are relatively smaller than piston and diaphragm pumps and are generally less expensive.
Disc pumps, with their non-impingement design are able to handle solids and fluids with
a high gas volume fraction but, like centrifugal pumps, are generally less efficient than
reciprocating pumps. Diaphragm pumps are capable of maintaining a constant rate
regardless of pressure fluctuations. They can handle very abrasive solids with limited
wear on the pump. They also excel at handling very viscous fluids and they can be
modified to handle up to 95% gas volume fraction. Like piston pumps, they have very
high efficiencies.
The potential of each of these pump technologies to meet the requirements for the
Mudlift Drilling System was examined in this thesis. The benefits and drawbacks of
each of these pump technologies were highlighted and modifications to meet the
demands of the mudlift system evaluated.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2571 |
| Date | 15 May 2009 |
| Creators | Oluwadairo, Tolulope |
| Contributors | Hans, Juvkam-Wold C. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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