Overbalance mud can pay off in well killing

Journal Article · Mon Feb 16 00:00:00 EST 1987 · Oil Gas J.; (United States)

OSTI ID:6892077

Bayless, J H; Bayless, J S

Contrary to conventional thinking, overbalance mud can safely be used in well killing operations. This permits large savings in rig time, which can be further increased by use of premixed muds. A side benefit of the procedure is a reduction in casing and casing seat pressures. Early publications of methods to control kicks by the constant bottom-hole pressure method cautioned against the use of muds heavier than kill weight mud (generally considered to be exact balance mud). The theory at that time was that heavier muds would create higher casing seat pressures and that balance weight results in the minimum casing seat and surface pressures. Most well control instructors to this day hold rigidly to this theory except for one recent publication where an uncontrolled heavy pill or slug is advocated. However, an analysis of a simplified well control model, which is covered in this article, shows that a controlled injection of overbalance mud is possible and indeed results in minimum casing seat pressures even lower than balance weight mud. The use of one circulation saves rig time and possible money.

• OSTI ID: 6892077
• Journal Information: Oil Gas J.; (United States), Vol. 85:7
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
NATURAL GAS WELLS
DRILLING FLUIDS
PRESSURE CONTROL
OIL WELLS
CONTROL THEORY
COST
DRILLING RIGS
FLUID MECHANICS
HYDRAULICS
TIME DEPENDENCE
WELL CASINGS
WELL PRESSURE
CONTROL
FLUIDS
MECHANICS
RESERVOIR PRESSURE
WELLS
020300* - Petroleum- Drilling & Production
030300 - Natural Gas- Drilling
Production
& Processing