Drilling Fluid.ppt

Drilling Fluid
The drilling fluid is a large and important part of drilling operation
Historical perspective
1901-The Sprindletop well introduced rotary drilling methods and drilling fluid
1920’s- Barite was first used for density
Other additives and systems followed:
-Bentonite
-Polymers
-Oil-based mud
Drill Fluid
-Air, natural gas or nitrogen-based systems
-1970’s-Safety and environmental issues in addition to performance and cost
-1990’s-Synthetic based muds now called non-aqueous drilling fluids or NAF
Function of drilling fluid or mud
Remove cuttings from the hole
Clean bottom of the hole (below bit)
Prevent flow of formation fluids
Control torque (reduce friction)
Retard corrosion
Deposit a thin filter cake
Transmit MWD information
Economically deliver a wellbore suitable for formation evaluation pletion
Prevent change in hole size
Aid in cement placement
Prevent lost circulation
Minimize formation damage
Assist in formation evaluation
Drill Fluid
Drilling fluids cannot do everything
Must decide on priorities
Number one function is to clean hole
If you do not clean the hole, you can not drill
Symptoms of poor hole cleaning
-Excessive torque
-Drag on connections
-Tight hole and bridges on trips
-Fill on bottom
Drill Fluid
Number two is to prevent blowouts
Blowouts can be catastrophic with loss of life, equipment and environmental damage
The mon additive for density is barite
Drill Fluid
Weight Material
Specific Gravity
Average Density ppg
Average lbs/bbl
Chemical Formula
Bairte


1470
BaSO4
Hematite


1819

Ilmenite


1680
TiO2Fe2O
Drill Fluid
Hematite and Ilmenite are not used very often in drilling fluids
Only for very high density drilling fluids
Bottomhole cleaning is primarily performed by the hydraulics and not the mud
-Mud additives generally reduce bottomhole cleaning
-Bit cleaning is less of a problem with dispersed mud systems
Drill Fluid
In most instances, hole lubricati