Engineered solutions to the hazards of oil based muds
In the drilling process, mud performs a number of functions requiring different physical and chemical properties and it is useful to consider how these are affected by the use of an oil based fluid. The first function of the mud is to transport cuttings to the surface, which in general requires a velocity of around 100-200 ft/min and a viscosity of 30-50 secs/qt. The mud should have sufficient viscosity and gel strength to ensure that the cuttings are transported from the cutting surface and that they do no sink back to the bottom should circulation be interrupted. Secondly, the mud also works as a cutting fluid to lubricate and cool the bit and to ensure the at it is working on a clean formation, and to assist cutting via the energy of the fluid jets from the bit nozzles. The third essential function of the mud is as a primary means of pressure control. The hydrostatic head of the column of mud serves to counter-balance the formation pressure at any depth and must be amenable to adjust to compensate for variations in pressure. Also, by measuring flow rates in and out of the hole, the volume of mud in the tanks and by monitoring whether the mud contains gas, fluids or hydrocarbons, a large amount of information about what is happening at the bit can be obtained. The fourth property of mud is to provide a filter-cake that lines the bore of the well, helping to support is and preventing the loss of mud to the formation or the ingress of fluids form the formation into the hold.
- OSTI ID:
- 6468739
- Report Number(s):
- CONF-870993-
- Resource Relation:
- Conference: Offshore Europe '87: SPE of AIME conference, Aberdeen, UK, 8 Sep 1987; Other Information: Technical Paper SPE 16546/1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DRILL BITS
PRESSURE CONTROL
DRILLING FLUIDS
CHEMICAL PROPERTIES
OIL WELLS
SLUDGES
BOREHOLES
ENGINEERING
FLOW RATE
GASES
HYDROCARBONS
HYDROSTATIC BEARINGS
MEASURING METHODS
MONITORING
PHYSICAL PROPERTIES
RESERVOIR PRESSURE
TANKS
VISCOSITY
BEARINGS
CAVITIES
CONTAINERS
CONTROL
DRILLING EQUIPMENT
EQUIPMENT
FLUIDS
ORGANIC COMPOUNDS
WELLS
020200* - Petroleum- Reserves
Geology
& Exploration
020300 - Petroleum- Drilling & Production
580203 - Geophysics- Geophysical Survey Methods- (1980-1989)
400201 - Chemical & Physicochemical Properties