Non-technical overview of permeability…or the lack thereof

Report
NON-TECHNICAL OVERVIEW
OF PERMEABILITY…OR THE
LACK THEREOF
CHUCK
AGENDA
2

Permeability

Calculation of Permeability

What Measurement Really Matters?
PERMEABILITY
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SPE
SPE PAPERS: PROOF THE SUBJECT IS COMPLEX
SPE 56813: Stress-Dependent Permeability, October 1999. Davies
SPE 131768: Petrophysical Considerations in Evaluating and Producing Shale Gas Resources, February
2010. Sondergeld; Newsham; Comisky; Rice and Rai
SPE 153480: Transient pressure Behavior for Dual Porosity Low Permeability Reservoir Based on
Modified Darcy’s Equation, April 2012. China University of Petroleum.
SPE 114168: The Characteristic Flow Behavior of Low-Permeability Reservoir Systems, February 2008.
Blasingame.
SPE 39657: Relative Permeability Curves: The Influence of Flow Directionand Heterogeneities, April
1998. Crotti; Inlab; Rosbaco.
SPE 59753: Low Permeability Gas Reservoirs and FormationDamage – Tricks and Traps, April 2000.
Hycal Research Laboratories.
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FLOW PRINCIPLE THAT WE LIVE BY:
Get KH Right
  =
 ∗ ℎ ∗  
  +   
k
h
s / xf
μ
∆P
5
SO WHICH PERMEABILITY ARE WE TALKING ABOUT?
 =
  ∗   ∗ ℎ
   ∗  
absolute
matrix
directional
radial
relative
air
manufactured
effective
fracture
vertical
6
WHAT WE ARE TRYING TO REPRESENT:
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CALCULATION OF PERMEABILITY
Prediction error
Error
History Match curve fit
Complexity
SAMPLING ERROR
What color clothing is in the
image?
10
SAMPLING ERROR
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A small data point can yield a
large error.
HOW DO WE INFER PERMEABILITY?
Well Test Evaluation
Well Performance Evaluation
Guess
Log Analysis
Reservoir Sample Size
Core Analysis
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Analogy
Well Test Evaluation - Well Performance Evaluation
Log Analysis - Core Analysis
HISTORY MATCH
Permeability
Volume
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Corresponds to
currently
contacted area
Assumed
drainage area

Rate Transient Analysis
 Normally use FMB to get A




Instead use EUR from Arps in
FMB to get A
Lower decline (flatten out)
during PSS flow and especially
for low perm reservoirs
Use A to match Blasingame
type curve
Output: range of k, Xf, A
WELL TEST / Rate Transient Analysis
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ROCK TYPING AND PERMEABILITY RELATIONSHIP
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PERM VS THICKNESS VS PVT VS DRAINAGE VS # FRACTURES VS #
CLUSTERS VS SATURATIONS VS EVERYTHING ELSE…WHICH ONE
MATTERS THE MOST?
PERMEABILITY EFFECT ON PRODUCTION PROFILE
4000 psi
180 F
30% SW
Perm: 5;1;.5;.05;.005 md
Porosity 8%
Net H 50 ft.
Area 640 acres
OGIP 18.7 BCF
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Well:
Depth 9000 ft.
Tubing flow 2in. ID
Cullender Smith Lift correlation
Surface flowing pressure 500 psi.
Completion: perforated, -2 skin
EFFECT OF PERMEABILITY THICKNESS:
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ADJUSTMENT WE LIVE WITH:
Pressure Dependency
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THE EFFECT OF OIL GRAVITY AND SOLUTION GAS ON PRODUCTION
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IS THE PERMEABILITY/POROSITY RELATIONSHIP IMPORTANT, OR IS IT MOSTLY THE
POROSITY(ROCK TYPE)?
Phie vs. IP
Effective Porosity
0%
8%
Phie*Fracs vs. IP
0%
8%
Extracted Synthetic Effective
Porosity along wellbore trajectory
24 Fracs
DRAINAGE AREA EFFECT:
4000 psi
180 F
30% SW
Perm: 5;1;.5;.05;.005 md
Porosity 8%
Net H 50 ft.
Area 640 acres
OOIP 9.3 MMBO
Well:
Depth 9000 ft.
Tubing flow 2in. ID
Completion: perforated, -2 skin
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Oil Properties:
38 API
900 Rs
BP 3746 psi
FVF 1.49
MATRIX PERMEABILITY OF UNCONVENTIONAL SYSTEM
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STIMULATION STYLE: WHAT DOES IT LOOK LIKE?
STIMULATION
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TRUE “RESERVOIR” IS REALLY ONLY FRACTURED AREA, OR IS IT?
Permeability will determine economic fracture spacing
Depleted Area (60% Press Depletion)
SRV EXAMPLE
Definition of SRV
WHAT ARE THE DRAINAGE EFFECTS OF CLUSTERS ON < 1000 ND?
Are all of these activating?
Traditional
Decline Curve
Analysis
Core
Acquisition
& Evaluation
Well Log
Acquisition
& Evaluation
Fluid
Acquisition
& Evaluation
Flowing
Pressures
Quantification
Reserves
Va
li d
at
io
n
Static
Pressures
Volumetric
GIP
(Static)
Va
lid
at
io
n
Contacted
GIP
(Dynamic)
Well
Performance
Analysis
Reservoir
Simulation
Well
Surveillance
& Monitoring
RESERVOIR PERFORMANCE– ENGINEERS TOOLS
•Storage Properties: f, & Sw
•Net Pay: h
•Dipole Logs: Stress Profile
•Fracture Model: Xf, Hf, & Cf
•Reservoir Model: k, Xf
•Pressure/Rate Analysis: net
pressure
•Type Curve Analysis: k, Xf &
kfw
•Flowing Material Balance:
drainage area
•Test model w/parameters
Log
Analysis
Rate
Transient
Frac
Modeling
Simulation
•Build model: IP/RTA
properties
•History match: k, Xf, & kfw
•Predict: Current & Future Well
Performance
*mod. Josh Hegg
BEST ANSWERS WIN !
BUT WHAT IS THE QUESTION?
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