Post on 10-Apr-2020
Onsite Isotope Logging Applications in Unconventional Petroleum Systems
Dallas Petroleum Club, March 8, 2019
Dallas, Texas
Andrew Sneddon, COO Paladin Geological Services
Dr. Sheng Wu, VP Technology Arrow Grand Technologies
Welcome
• Greetings and Thank you for attending
• Acknowledgments
• My background
• Topic today
Objectives
The objectives for this workshop are to introduce the applications and value of integrated isotope logging
with current drilling programs to provide real-time assessment and interpretation relating to petroleum
systems, sweet spot zones. Furthermore, this course will provide an in-depth glance at the how Paladin is
providing geologists/geochemists with a new dimension of data during drilling to assist with various
conventional tools relating to rock properties, oil and gas genetics, reservoir properties and the ability to
quantify multi-stacked zones of interest and high production zones
“
”
The true value of isotope
geochemistry is to create a
bridge between geochemists,
geologists and engineers
Outline/Chapters
Methods/Analysis Isotope InterpretationsIntroduction Reservoir Isotope Modeling
Section 1 Section 2 Section 3 Section 4
MODULE 1 | INTRODUCTION
Introduction : What are Isotopes??
Bohr Model : Atomic Nucleus
• Central nucleus (+) charge (predominate mass of
atom)
• Orbiting electrons (-) charge
• Nucleus
• (+) charge protons, Z & neutrons, N (neutrally
charged), similar mass
• Neutron, N slightly heavier than Protons, Z
• ∑N+Z give mass number, # of nucleons A(A=N+Z)
• For a given atom, there are atoms with different
mass numbers (A), therefore different nucleons
(different number of neutrons) these are called
Isotopes
Carbon Isotopes
Hydrogen Isotopes
1H 2H 3H
Similar concept for other atoms
Section 1 | Introduction
Introduction : Stable Isotopes relative to a standard
• Differences in isotopic composition are very small, and
denoted as a delta value, δ
δ =𝑠𝑎𝑚𝑝𝑙𝑒 𝑖𝑠𝑜𝑡𝑜𝑝𝑒 𝑟𝑎𝑡𝑖𝑜 − 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑖𝑠𝑜𝑡𝑜𝑝𝑒 𝑟𝑎𝑡𝑖𝑜
𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑖𝑠𝑜𝑡𝑜𝑝𝑒 𝑟𝑎𝑡𝑖𝑜* 103
• For example, Carbon:
δ𝟏𝟑𝑪 =ൗ
𝟏𝟑𝑪 𝟏𝟐𝑪𝒔𝒂𝒎𝒑𝒍𝒆− ൗ
𝟏𝟑𝑪 𝟏𝟐𝑪𝒔𝒕𝒂𝒏𝒅𝒂𝒓𝒅
ൗ𝟏𝟑𝑪 𝟏𝟐𝑪𝒔𝒕𝒂𝒏𝒅𝒂𝒓𝒅
∗ 𝟏𝟎𝟑
• In our world, delta (δ) is the deviation relative to the
standard, expressed as an integer in parts per thousand or
per mil, denoted ‰
• If the Isotope value is more positive, it is heavier
• If the Isotope value is more negative, it is lighter
• The more positive the delta value, the more enriched in the
heavier isotope relative to the standard (0)
Carbon Isotopes
Hydrogen Isotopes
1H 2H 3H
Similar concept for other atoms
0standard
+10-10
Lightest to Heaviest
Section 1 | Introduction
Introduction : Stable Isotopes relative to a standard
Carbon Isotope Delta, δ values in earth
• CO2 (atm) : 8 ‰
• Ocean : -10 ‰
• Plants, Kerogen, coal : -8 ‰ to -55 ‰
• Oil : -20 ‰ to -55 ‰
• Natural Gas : -20 ‰ to -90 ‰
• Biogenic
• Mixture/overlap
• Thermogenic
Sources: Stable Isotope Geochemistry Stable isotopes are used in CCS to look for leakage of CO2 into overlying aquifers or into the surface environment, Corey FlemingEarth System Research Library Stable and Radiocarbon Isotopes of Carbon Dioxide
Section 1 | Introduction
Introduction : Key Terms/Understandings
Kinetic Isotope Effects
• Diffusion versus Darcy’s Flow
• Chemical or physical properties
• Heavier isotopes are more stable
• Lighter isotope bonds are weaker than heavier isotope bonds
Isotope Fractionation
• Partitioning of isotopes between 2 substances or 2 phases of
the same substance with different isotope ratios
• In our course and application: free gases vs. adsorbed gases,
time and flow mechanics are the main causes of isotope
fractionation
Sources: Stable Isotope Geochemistry Stable isotopes are used in CCS to look for leakage of CO2 into overlying aquifers or into the surface environment, Corey FlemingEarth System Research Library Stable and Radiocarbon Isotopes of Carbon Dioxide
Hydrocarbon Generation is a chemical process
Isotope fractionation is a chemical process
k13/k12 = (A13/A12) e -DDE/RT
Time
Experimental
Oil and Gas
Section 1 | Introduction
0%
20%
40%
60%
80%
100%
120%
2000 2004 2008 2012 2016
Unconventional resources require new
tools for evaluating a much more
difficult petroleum system than
conventional drilling
• Tight Rock = more data to acquire from
rocks themselves!
• Rock mechanics and flow pathways
• Diffusion vs. Darcy’s flow
• Lithology – conventional tool struggles
• Source identification
The emergence of
Unconventional Systems
2016~70% of all wells drilled in USA
2000~100% of all wells drilled in USA
Sources: U.S. Energy Information Administration, based on drillingInfo Inc. and IHS Market
http://seekingalpha.com/article/3966373-newfield-exploration-transformation-progress?page=2
Evolution of Conventional vs Unconventional US
Drilling
Section 1 | Introduction
The 3 P’s Differences between Unconventional/Conventional Systems
Unconventional
• Porosity are self-generated nanopores through secondary cracking; not necessarily preconnected ---poor perm
• Pressure is obscured by capillary pressure and seal, well-head or bottom hole pressure not direct
• Perm no longer correlated with porosity
Conventional
• Porosity are compacted from initial cracks, preconnected, except carbonate reservoirs where strong diagenesis could generate similar nano porosity as unconventional
• Pressure could be measured through well-head or bottom hole pressure
• Perm generally have positive correlation with porosity
Section 1 | Introduction
Natural Gas Isotope Applications
• Isotope Reversal/Roll-Over
• Isotopic Signature profiling δ13C1-C3
• Genetic Origins of gas
• Source rock correlations
• Maturity Modeling
• Reservoir Compartmentalization
• Instanteous vs. Accumulated storage
• Secondary Cracking Indicators
• Dry gas vs. Wet Gas quantification
Oil Isotope Applications
• Sweet Spot Prediction (SSP)
• Isotopic Signature profiling δ13C1-C3
• Multi-stage degassing correlation
• Maturity Modeling
• Lateral Production Zonal Analysis (LPZA)
• Rock properties- nano-porosity
• Adsorbed vs. Free Gas Quantification
• Reservoir Compartmentalization
• Production decline modeling
Section 1 | Introduction
Petroleum Generation Cycle
Sources: Cain’s Petrophysical Handbook | Killops and Killops, 2010 | Peters and others, 2007 | Huc, 2003 | Michael Lewan
• Maturity determines generation cycle of
hydrocarbons
• Immature→Oil Window→Wet Gas Window→
Dry Gas Window→Overmature
• Kerogen→Bitumen→Crude Oil→Natural Gas,
H2S, Pyrobitumen
• Isotope Geochemistry→ Genetic Origin
tracing→Maturity Modeling
Section 1 | Introduction
SECTION 2 | METHODS/ANALYSIS
Module 2 | Wellsite Set-up and Methods
• 2 different Methods (services) Paladin provides
• Mud Gas Isotopes (In-line)
• Headspace Gas Isotopes (manual injections)
• Instrument: GC-IR2 Compound Specific Isotope Analyzer
• New technology (QCL + HWG)
• Combustion methodology
• Does NOT use typical Mass Spec analysis
• δ13C1-C3 Isotope Ratios
• C1-C6 Concentrations
• Cycle time ~ 5 minutes
• Precision: ±0.3 per mil C1-C3
• WITS enabled/Real-time logging
• Auto-dilution technology for Hi-Res sampling
of mud gas isotopes
Wellsite Schematic
• Auto-dilution process (in-line)
• Deviation/Instrument stability
• Quality assurance and lab comparison
• Wellsite Sampling process
• Differences of instrument options globally
Module 2 | Wellsite Set-up and Methods
Part B | Isotope Logging while Drilling
• QA/QC Protocols
• Process/Workflow
MODULE 2 | ON-SITE ISOTOPE LOGGING
1
2
QA/QC is critical for any isotope analysis both in the
field and on location
The difference between -40.1 and -41.5 is critical, i.e., slight
differences in isotope ratios must be verified and accurate.
Common concerns for field isotopes:
• Trailer temperature and stability
• Power stability
• Experienced personnel
• Data drifting
QA/QC- Data AnalysisTechnicians constantly remotely monitoring
instrument performance and stability
Instrument CheckExtensive sensor technology inside the
spectrometer to ensure equipment data and
performance tracking
Module 2 | Isotope Logging while Drilling QA/QC Protocols
3TrainingAll personnel are qualified and trained in
Paladin’s isotope logging certification class
The standard deviation for 13C1,2,3 are about 0.2~0.25‰ (1) due to smaller temperature changes
δ13C1 δ13C2 δ13C3
PHASE 1 (A): Onsite Isotope Logging
Headspace Gas Isotopes
δ13C1-C3
C1-C6 Concentrations
30 ft Intervals, 10-15 ft interval through target zones
Multi-tested: Rd 1 @ 12 hrs. after collection, Rd 2 @ 1
week after collection
Sweet Spot Prediction (relative perm, pressure,
saturation zones)
Mud Gas Isotopes
δ13C1-C3
C1-C6 Concentrations
Auto Sampled
Every 5 minutes = data point
Hi-Resolution Data
Maturity Model
Reporting
.xls file data set
.pdf Plots
LogBoxTM Interpretation
Module 2 | Isotope Logging while Drilling
Drilling Analysis Interpretation Reporting
Process/Workflow
1
2
Two Tiers of Paladin Isotope Logging
Tier 1-Mud Gas IsotopesThis service only measures mud gas isotopes
in line at very high resolution (no jars)
Tier 2- IsoZoneTM
This service measures both the mud gas
isotopes in line and multi-tested jars (time)
headspace gas isotopes
Module 2 | Isotope Logging while Drilling Process/Workflow
Measurement Time measured
Mud Gas δ13C1-C3 + C1-C6 Conc. Immediately (like gas detection)
Round 1 MeasurementHeadspace δ13C1-C3 + C1-C6 Conc.
Up to 6 hrs. after collection
Round 1 MeasurementHeadspace δ13C1-C3 + C1-C6 Conc.
Up to 2 weeks after collection
Measurement Program
Time (Hours after collection)
• Gas release from cuttings is a very dynamic process
• Time-sensitive information (6 hrs versus 1-2 weeks)
Module 2 | Isotope Logging while Drilling Process/Workflow
Working in coincidence with Mudlogging
Key Points:
• Cuttings analysis provides lithology and other geologic information
• First time in millions of years these rocks have reached the surface
• 1 chance to log while drilling just like logging
• Isotope logging provides a new dimension of data and interpretative value
• Isotope logging provides data that can be used during drilling, during
completions and production of oil and gas
Unconventional Oil & Gas Systems
MODULE 3 | Isotope Geochemistry Interpretation
UOG Matrix-
Fluid
Nano fluidics
Isotope 13C
Pore Pressure
Pore throat
Fluid-rock
Optimize Fracking
New concepts in isotope headspace
analysis for Sweet Spot identification and
completion designs in Unconventional Oil
& Gas
• Unconventional O&G storage and production are different from conventional counterparts
• Unconventional wisdoms in OOIP/OGIP, Preservation and SSID
• Rock-fracking fluid interaction plays crucial role in Unconventional O&G production
• Unconventional wisdoms in optimization of rock-specific stimulation, i.e. fracking fluid
• How Isotope fractionation or headspace dynamic measurements help?
Unconventional Oil & Gas
1
2
Challenges for Shale Gas
• Low contrast of TOC/GR/Porosity
• GIP models often misrepresent reality
• Sweet Spot locations
• Production allocation (fracking design)
• Porosity could be deceiving
Mud gas wetness log and isotope log for Sweet Spot
SSID identify sweet spots in stacked tight gas formations
Porosity/PermeabilityTwo of the most important parameters to
evaluate reservoir potential and productivity
PorosityAffects how much gas/oil can be stored in the
shale and to some extent, how easily gas/oil
is transported, related to oil/gas productivity
3Permeability Affects how easy the gas/oil can flow in shale
layers, enhanced by fracking
Unconventional Oil & Gas
Original Model Example
• Larger the difference, the better the permeability
• Based on 1 stage measurement (lab)
• Based on diffusion alone, does not depend on pore throats or pressure
• Must consider Knudsen Number and calculate 3 types of flows
• Doesn’t factor reality of critical influences (chips size, water versus no water,
etc.)
• Heavier shift→ smallest pore throats and poorest permeability
• Adsorption favoring the lighter δ13C
𝐽𝑎 = −(𝑟2
8𝜈 +
𝑐𝑟2𝐾𝑛
2𝜈 +
4𝑟
3
2𝑀
𝜋𝑅𝑇)∇𝑝 (1) or 𝐽𝑎 = −(𝐹
𝑟2
8 +
4𝑟
3
2𝑀
𝜋𝑅𝑇)∇𝑝
Darcy Slippage Knudsen Diff.
Unconventional Oil & Gas
Module 3 | Unconventional Oil (Liquids)
Eagle Ford Shale Example
BJH Desorption dV/dD pore volume
Po
re V
olu
me
(cm
3/g
)
Pore diameter (A)
• Stage-wise degassing→ like water stimulation
• Links fractionation with seal and stimulation
• The larger fractionation CH4 in 10,780’ linked to largest
nano pore volume and smallest pore throat
• Proves the dynamic process of headspace gas isotopes
fractionation, lighter then heavier, not static or
monotonically heavy
• TOC not the only control factor (10760 highest)
• Porosity not correlating with Perm
Sample 10,720:
Pore volume is mainly
contributed by mid-sized pores
with diameters of 50-200A
(Generally broad distribution)
1. Pore volume is the largest of
the three samples;
2. Pore volume is mainly
contributed by smaller-
sized pores with
diameters of 30-50A.
3. Largest total pore volume
and smallest pore
diameters result in larger
potential for gas storage
and probably larger
isotope fractionation.
1. Pore volume is the
minimum of the
three samples;
2. Pore volume is
mainly
contributed by
mid-sized pores
with diameters of
50-200A.
Module 3 | Unconventional Oil (Liquids)
Eagle Ford Shale Example
• Stage-wise degassing→ like water stimulation
• Links fractionation with seal and stimulation
• The larger fractionation CH4 in 10,780’ linked to largest
nano pore volume and smallest pore throat
• Proves the dynamic process of headspace gas isotopes
fractionation, lighter then heavier, not static or
monotonically heavy
• TOC not the only control factor (10760 highest)
• Porosity not correlating with Perm
Module 3 | Unconventional Oil (Liquids)
Eagle Ford Shale Example 2
• Stage-wise degassing→ like water stimulation
• Links fractionation with seal and stimulation
• The larger fractionation CH4 in 9,650’ linked to largest
nano pore volume and smallest pore throat
• Proves the dynamic process of headspace gas isotopes
fractionation, lighter then heavier, not static or
monotonically heavy
• TOC not the only control factor (9,640 highest)
• Porosity not correlating with Perm
• Sweet Spot 9,650 has lowest TOC, largest total
fractionation, largest porosity and surface area
• Also indicative of smaller permeability due to strongest
isotope variations throughout the degassing
experiement
Vertical and Horizontal Examples- Auto Interpretation software
Hi-Resolution Mud Gas Isotopes
Multi-stage HS concentration measurements (Rd 1 versus Rd 2)
Relative Perm/Pressure Indicator (methane isotopes)
Maturity Modeling using Isotopes and Kerogen Type
Onsite Isotope Logging for Sweet Spot-
Permian
Module 3 | Unconventional Oil (Liquids)
Rd 1 Observations:
• Initial methane isotope ratio (headspace) significantly heavier than methane
isotope ratio of mud gas
• No visible increase in mud log gas detection gas
• No visible increase in S1/TOC
• No visible saturation in Rd 1 headspace C1-C5 concentration measurements
Onsite Isotope Logging for Sweet
Spot- Anadarko basin
Module 3 | Unconventional Oil (Liquids)
Rd 1
Rd 2
Rd 2 Observations:
• Large fractionation shift >1,000 ft above Woodford Sh. ~250-300 ft. thick
• Large increase in C3-C5 headspace concentration measurements in Rd 2 (same
injection vol, same sample)
• Saturated reservoir discovered, very tight rock, not visible in S1/TOC (dominated
by light hydrocarbons), not visible in mud gas because heavier hydrocarbons not
released yet.
Part B | Shale Gas
MODULE 3 | Isotope Geochemistry Interpretation
Module 3 | Unconventional Oil (Liquids)
Isotope Interpretations- MATURITY
• Mud Gas Isotope Maturity modeling
based on Kerogen Type
• Reversal identification for overmature
systems
Module 3 | Shale Gas
Depth
Dry Gas Well ExampleWet Gas Well Example
13832 Santa Fe Crossings Dr. Edmond, OK 73013
Andrew.Sneddon@paladingeo.com 405-463-3270