Peh: Drilling Problems and Solutions Publication Information Petroleum Engineering Handbook

Loss of Circulation
Definition
Lost-Circulation Zones and Causes
Prevention of Lost Circulation
Remedial Measures
Hole Deviation
Definition
Causes
Drillpipe Failures
Twistoff
Parting
Collapse and Burst
Fatigue
Pipe-Failure Prevention
Borehole Instability
Definition and Causes
Types and Associated Problems
Principles of Borehole Instability
Mechanical Rock-Failure Mechanisms
Shale Instability
Wellbore-Stability Analysis
Borehole-Instability Prevention
Mud Contamination
Definition
Common Contaminants, Sources, and Treatments
Producing Formation Damage
Introduction
Borehole Fluids
Damage Mechanisms
Hole Cleaning
Introduction
Factors in Hole Cleaning
Contents

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Hydrogen-Sulfide-Bearing Zones and Shallow Gas
Equipment and Personnel-Related Problems
Equipment
Personnel
Nomenclature
References
General References
SI Metric Conversion Factors
During drilling operations, a pipe is considered stuck if it cannot be freed and pulled out of the
hole without damaging the pipe and without exceeding the drilling rig ’ s maximum allowed
hook load. Differential pressure pipe sticking and mechanical pipe sticking are addressed in this
section.
Differential-pressure pipe sticking occurs when a portion of the drillstring becomes embedded in
a mudcake (an impermeable film of fine solids) that forms on the wall of a permeable formation
during drilling. If the mud pressure, p
m
, which acts on the outside wall of the pipe, is greater
than the formation-fluid pressure, p
ff
, which generally is the case (with the exception of
underbalanced drilling), then the pipe is said to be differentially stuck (see Fig. 10.1). The
differential pressure acting on the portion of the drillpipe that is embedded in the mudcake can
be expressed as