onsite isotope logging applications in unconventional petroleum … · 2019-05-18 · onsite...

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


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


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


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


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


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


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 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


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.


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.


Eagle Ford Shale Example







monotonically heavy

• TOC not the only control factor (10760 highest）



Eagle Ford Shale Example 2







monotonically heavy

• TOC not the only control factor (9,640 highest）


• 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


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


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


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

[email protected] 405-463-3270

onsite isotope logging applications in unconventional petroleum … · 2019-05-18 · onsite...

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