Transcript Underbalanced Drilling Technology

Introduction to
Underbalanced
Drilling Technology
(M2)
Wellsite UBD Equipment
Nitrogen
UB operators
Geology
Separator
Rotating Head
Mud Treatment
Camp
UB DRILLING - JOBS
1997 Underbalanced Drilling Jobs
Geographic Distribution
Canada
M iddle East
Europe
South America
US
Far East
©1998 Spears & Assoc.
UBD - Types
• Normally Pressured Reservoirs
Applications for normal to above normal
pressured reservoirs utilizing fluid systems
in a controlled flow (mudcap) drilling
technique.
• Depleted Reservoirs
Where a multi-phase circulating fluid is
necessary to achieve required Bottom Hole
Circulating Pressure (BHCP) underbalanced or with minimal overbalance.
Barriers to UB Drilling
REGULATORY BARRIERS
to
UnderBalance Drilling
 The
regulators
need assurance
and details
BARRIERS TO UB D&C
Regulatory
Lack
of Standards
Lack of knowledge
Little statistical history
Concern about well control
Environmental questions
OPERATORS BARRIERS
 The
Operator
needs
experience and
confidence.
OPERATORS PROBLEMS
Unfamiliar
risk
Lack
with the system
of the new
of experienced people
Economics - Too expensive
Concern- liability
Concern- well bore stability
REASONS FOR UB GROWTH
 There
are
driving
economic
reasons
REASONS FOR UB GROWTH
Depleted
reservoirs
Awareness of skin damage
Limits of lost circulation matl.
Cost of differential sticking
REASONS FOR UB GROWTH
Service
co. competition
Trade journal publications
Horizontal drilling
Consultants available
TECHNICAL IMPROVEMENTS
 We
were not
ready to put all
of this together
until the 1990’s
TECHNICAL IMPROVEMENTS
Compressor
Evolution
Hammer drills
Nitrogen
Increased
availability
Reduced cost
On site generation
TECHNICAL IMPROVEMENTS
Recyclable
foam systems
Better gas separators
Closed loop circulation
Hydraulics models
Improved rotating heads
Wire line wet connect
TECHNICAL IMPROVEMENTS
Improved
MWD
Rig assist snubbing units
Coiled tubing equipment
Non-damaging drilling fluids
Top drive
WORKING ON
Well
Control Concepts
Deployment valves
Casing Drilling
Expandable casing
Expandable sand screens
Retractable bit
COMPLETION TECHNIQUES
Improved
gravel packing fluids
Improved completion fluids
General technique
improvement
Reasons for UB drilling
 Lost
circulation
Reasons for UB drilling
 Lost
circulation
 Faster Drilling
Reasons for UB drilling
 Lost
circulation
 Faster Drilling
 No Differential
Sticking
Reasons for UB drilling
 ...
 Reduce
Reservoir
Damage
Reasons for UB drilling
 ...
 Reduce
Reservoir
Damage
 Improve Prod.
Evaluation
Effect of Skin on Production Rates
BOPD
1,000
800
600
400
200
0
-3 -2 -1 0
5
SKIN
10
15
Physical Limitation to UBD
• Borehole Instability
• Unconsolidated Sands
• Weak Formations
• Geopressured Shales
• Salt Beds
• Inadequate Casing
UBD is another tool in the toolbox,
not a Panacea.
Production Limits to UBD
 Permeability
is
so low the zone
needs to be
fraced.
 Zones must be
isolated
Types of Flow Regimes
LIQUID
AERATED
LIQUID
FOAM
MIST
GAS
Fluid Phase Continuity
AIR/GAS
WATER
FOAM
(0-97% AIR)
MIST
(97-100% AIR)
Generalized
“Fluid” Systems
CONTROL EQUIPMENT
Equipment - Rotating Head
• Shaffer Rotating Blow-Out Preventor
• 2,500 psi rotating - 5,000 psi static
Closed Loop Circulation
System
FLARESTACK
SEPARATOR
SAMPLE
CATCHERS
OIL
TANKS
TOP
DRIVE
SYSTEM
NITROGEN
PUMPERS
CHOKE
MANIFOLD
R-BOP
WATER
TANKS
RETURN
CUTTING
RIG
MUD
TANKS
RIG
PUMPS
N2 / FLUID
MIX
Choke Manifold
Equipment - Lots More
To shale shaker
ESD
Manifold
Sample
catchers
Willis choke
Flare
Separator
200 psi vessel
Rig Manifold
Choke
Oil storage/transport
HCR
Water returned to tanks
Choke
Flare pit
AIR DRILLING
A brief summary
Air Drilling
• Air/Gas drilling (“dust”) is a technique used in
areas where the formations are “Dry” i.e., there
is no influx of water or liquid hydrocarbons.
• This medium requires significant compressed
gas volumes to clean the well with average
velocities of over 3,000 ft per minute.
Air Drilling Dusting
Air Drilling Benefits
•Increased Rate of Penetration
•Reduced Formation Damage
•Improves Bit Performance
•Lost Circulation Control
•Continuous Drill Stem Test
Air/Dust Drilling Layout
Air Drilling Waited upon
Large Portable Compression
Simple and convenient to drill with air inexpensively and anywhere.
Misting
Addition
of 6 to 30 bbl/hr of
fluid to the air stream.
Clean and lubricates the bit
Carries the cuttings to the
surface as a mist or more
normally in a modified two
phase flow.
FOAM DRILLING
Basic Comments
TT96-86
42
Foam Drilling
• The most versatile of the gas-generated
systems.
•
•
•
•
•
•
Effective operating range from 0.2 to 0.6 s.g.
Mixture of gas phase and foaming solution.
Foam flow varies with depth in the hole.
Adjustable effective BHP.
Enhanced lifting and well bore cleaning.
A “displacing medium”, not a propelling
medium.
Foam (Heading)
Improved Hole Cleaning
Foam Drilling Benefits
•
•
•
•
•
•
•
Faster Penetration rate
Low Air requirements
Low fluid requirements
Low Hydrostatic head
No damage to formation
Continuous Drill Stem test
Best for large holes
Mist or Foam Drilling Layout
GASEATED
OR
AERATED
DRILLING
Mist
Water
Gas
Transition
Gaseated
Aerated Fluid
• Gasification of Primary Drilling Fluid.
• Initially designed as a technique to lighten
mud to reduce lost circulation.
• Methods
• Standpipe injection
• Jet Sub
• Parasite String
• Dual Casing String
• As an UB fluid, it is easiest to control in small
holes.
Parasite String
• Small injection string run simultaneously
with intermediate casing.
• Injected gas does not affect
bit hydraulics.
• Injected gas does not effect
MWD
Jet Sub
• Similar to Parasite String
• Gas induced thru drill pipe
• Selective jet sizing dictates
amount of air to be injected
• Jets are Similar to Bit Jets
Parallel Casing String
(Teichrob)
N2 /air
N2 /water
N2 /air/water/oil
150 m TVD, 150 m MD
89-mm (3-1/2 in.) Drill Pipe
244.5-mm (9-5/8 in.) Intermidiate Casing
o
177.8-mm (7 in.) Tie Back Liner
724 m MD at
64o inclination
12 m Slotted
Joint
892 m MD
at 90 o Inclination
694 m TVD
159-mm (6-1/4 in.)
Hole Diameter
Foam Cement
o
TD = 1,440 m MD at 90 o
Inclination, 696 m TVD
Aerated Fluid Layout
Aerated Drilling Problems
Compressor/N2
Cost
Rotating BOP’s
Solid/Liquid/Gas
Separation
Corrosion
Hydraulic Calculations
Vibration
High Torque/
Drag
Borehole Stability
Cuttings Lifting
Fluid Influx
Fire/
Explosions
Underbalanced
Completion
MWD Transmission
END
OF
INTRODUCTION