Chapter 1 - Routine Measurements

1.01 Intro to Tight Rock Core Analysis (19 min.) Sample Lesson
1.02 Workflows (14 min.)
1.03 Core Preparation - Part 1 (25 min.)
1.04 Core Preparation - Part 2 (12 min.) Quiz: 1.04 Core Preparation - Part 2
1.05 Porosity - Part 1 (6 min.)
1.06 Porosity - Part 2 (Pore Types) (15 min.)
1.07 Porosity - Part 3 (Measurement) (16 min.)
1.08 Porosity - Part 4 (Grain Density/Bulk Volume) (18 min.)
1.09 Porosity - Part 5 (GRI Method) (14 min.) Quiz: 1.09 Porosity - Part 5 (GRI Method)
1.10 Pore Size Distribution - Part 1 (8 min.)
1.11 Pore Size Distribution - Part 2 (LPA) (20 min.)
1.12 Pore Size Distribution - Part 3 (SANS/USANS) (11 min.) Quiz: 1.12 Pore Size Distribution - Part 3 (SANS/USANS)
1.13 Permeability - Part 1 (16 min.)
1.14 Permeability - Part 2 (Klinkenberg Correction) (13 min.)
1.15 Permeability - Part 3 (Standards for Tight Rocks) (7 min.)
1.16 Permeability - Part 4 (Measurement) (11 min.)
1.17 Permeability - Part 5 (USS Perm. - Crushed-Rock) (16 min.)
1.18 Permeability - Part 6 (Drill Cutting) (8 min.)
1.19 Permeability - Part 7 (Drill Cutting - 2) (17 min.)
1.20 Permeability - Part 8 (Slabbed Core) (20 min.)
1.21 Permeability - Part 9 (Pulse-Decay) (14 min.)
1.22 Permeability - Part 10 (Method Comparison) (16 min.)
1.23 Permeability - Part 11 (Pore Throat Size) (6 min.)
1.24 Permeability - Part 12 (Fracture Permeability) (24 min.) Quiz: 1.24 Permeability - Part 12 (Fracture Permeability)
1.25 Stress Dependence - Part 1 (18 min.)
1.26 Stress Dependence - Part 2 (Biot Constant) (6 min.)
1.27 Stress Dependence - Part 3 (Facture Compressibility (10 min.)
1.28 Permeability & Stress-Sensitivity Summary (12 min.) Quiz: 1.28 Permeability & Stress-Sensitivity Summary
1.29 Mercury Intrusion Capillary Pressure (MICP) - Part 1 (23 min.) Quiz: 1.29 Mercury Intrusion Capillary Pressure (MICP) - Part 1
1.30 MICP - Part 2 (NUTECH Study) (18 min.)
1.31 MICP - Part 3 (Characterizing Hydraulic Rock Types & Flow Units) (9 min.)

Chapter 2 - Special Core Analysis

2.01 Special Core Analysis Overview (7 min.)
2.02 Wettability - Part 1 (18 min.)
2.03 Wettability - Part 2 (Video Example) (13 min.)
2.04 Wettability - Part 3 (Effect of Scale) (14 min.) Quiz: 2.04 Wettability - Part 3 (Effect of Scale)
2.05 Liquid Permeability - Part 1 (24 min.)
2.06 Liquid Permeability - Part 2 (Gas vs. Liquid) (13 min.) Quiz: 2.06 Liquid Permeability - Part 2 (Gas vs. Liquid)
2.07 Relative Permeability - Part 1 (12 min.)
2.08 Relative Permeability - Part 2 (Dacy Method) (13 min.)
2.09 Relative Permeability - Part 3 (Modified Dacy Method) (18 min.)
2.10 Relative Permeability - Part 4 (Crushed Rock Methods) (19 min.) Quiz: 2.10 Relative Permeability - Part 4 (Crushed Rock Methods)
2.11 Imbibition (16 min.)
2.12 Core-Flooding (25 min.)
2.13 Additional Huff-n-Puff Studies - Part 1 (23 min.)
2.14 Additional Huff-n-Puff Studies - Part 2 (Impact of Induced Fractures) (21 min.)
2.15 Additional Huff-n-Puff Studies - Part 3 (Effect of Water Saturation) (26 min.) Quiz: 2.15 Additional Huff-n-Puff Studies - Part 3 (Effect of Water Saturation)
2.16 Mechanical Properties - Part 1 (7 min.)
2.17 Mechanical Properties - Part 2 (Microhardness) (21 min.)
2.18 Elastic/Mechanical Properties - Part 1 (Sonic Velocity) (12 min.)
2.19 Elastic/Mechanical Properties - Part 2 (Montney/Duvernay Comparison) (20 min.)
2.20 Elastic/Mechanical Properties - Part 3 (Ultrasonic) (23 min.)
2.21 Mechanical Properties - Part 3 (Static Measurements) (6 min.)
2.22 Mechanical Properties - Part 4 (Indirectly from Cuttings) (10 min.)
2.23 Poroelasticity & Non-Darcy Flow (31 min.) Quiz: 2.23 Poroelasticity & Non-Darcy Flow

Chapter 3 - Case Studies

3.01 Case Study Introduction (2 min.)
3.02 Case Study #1 - Part 1 (27 min.)
3.03 Case Study #1 - Part 2 (26 min.)
3.04 Case Study #2 - Part 1 (20 min.)
3.05 Case Study #2 - Part 2 (14 min.)
3.06 Case Study #3 - Part 1 (13 min.)
3.07 Case Study #3 - Part 2 (21 min.)
3.08 Case Study #3 - Part 3 (6 min.) Quiz: 3.08 Case Study #3 - Part 3

Tight Rock Core Analysis / Chapter 1 - Routine Measurements

Lesson 1.01 Intro to Tight Rock Core Analysis

Access All SAGA Wisdom Training content Subscribe

Already a member? Sign in

Access All SAGA Wisdom Training content Subscribe

Already a member? Sign in

Transcript

01. Lesson 1.01: Intro to Tight Rock Core Analysis 02. Course Outline 03. Course Outline...04. Introduction 05. Introduction - 2 06. Introduction - 3 07. Introduction - 4 08. Introduction - 5 09. Introduction - 6 10. Course Learning Objectives

01. Lesson 1.01: Intro to Tight Rock Core Analysis

Hi there, I'm Chris Clarkson with the University of Calgary and I'll be your instructor for Tight Rock Core Analysis. My coconspirator is Dr. Amin Ghanizadeh, who is a research associate and the laboratory manager for Tight Oil Consortium. So he and I largely supervised a lot of the analyses and research that we present in this class.

02. Course Outline

So I'll begin with an outline. In our introductory section, we'll first provide a few basic facts about unconventional reservoirs that will guide us when we're talking about the various analyses and methodologies that were used for tight core analysis.
We'll then launch into a discussion of the course learning objectives, where we give you a few specific key points that we would like you to take away from this class.
In the field development and experimental workflow section, we'll first talk about a field development workflow that we have been referring to for several years now that allows one to optimize development of a field and that places in context the use of core based analysis or experimental techniques that we'll discuss in this class. We'll then look specifically at an experimental workflow that outlines the routine core analysis workflow that we use in Tight Oil Consortium and that'll provide a framework for our discussion of routine core analysis.
So in terms of the actual analysis methods that we'll discuss, we'll start with routine measurements. So by routine measurements, we're referring to those measurements that are typically performed by a commercial laboratory. So these discussion items include core preparation, some key steps that one must take before performing any sort of analysis on tight rocks. We'll talk about porosity and pore size determination and both some routine methods and a couple of maybe not so routine methods for that. We'll talk about a very important property, which is permeability estimation. And for this, we'll talk about not onlymatrix permeability estimation but also fracture permeability estimation, those 2 key components that we need to understand for unconventional reservoir development. We'll talk a little bit about stress dependance of porosity and permeability. And then we'll finish up with another routine method, mercury intrusion:capillary pressure, which is used to evaluate several properties including pore-throat distributions and permeability.

03. Course Outline...

After we've covered the routine core analysissection, we'll then launch into what we refer to as special core analysis, which isn't so commonly performed in commercial laboratories. And these include those properties of the rocks that allow you to characterizemultiphase flow, for example.
So we start with a discussion of wettability or fluid rock interaction in general. And although macro-wettability is something that is commonly done in commercial labs, one of the things that our group has specialized in over the past few years is micro-wettability determinations, so understanding fluid rock interaction at the micro scale.
We'll then talk about liquid permeability measurement. A lot of what we'll discuss in the routine core analysis will focus on gas measurements, gas permeability measurements but of interest today is permeability to, for example, water, brine and oil.
So we'll talk about how we're able to perform those measurements and that leads us naturally into a discussion of relative permeability. So both liquid-liquid relative permeability as well as gas-liquid rel perm. So we'll show you some specialized techniques that we've developed specifically for that.
And then we're going to launch into a discussion of incremental oil recovery methods. So we'll talk about fluid imbibition and specifically the addition of surfactants for incremental oil recovery and how we're doing that in the laboratory. We'll talk about gas injection techniques. So huff and puff methodologies, we've developed a specialized technique for trying to reproduce huff and puff process in the laboratory.
And then finally, we'll finish up with a discussion of rock mechanical properties, which is critical for understanding drilling and completion design.
And then lastly in this class, we'll focus on case studies that are really attempts to kind of summarize a lot of the things that we've learned from a theory base in the class.
So Case Study 1 is actually a new permeability estimation technique that our laboratory has derived that provides a methodology that allows us to use rate transient analysis theory applied to core analysis. So the case study is titled "A New Low-Permeability Reservoir Core Analysis Method Based on Rate Transient Analysis Theory". And the appeal of this method is that we're reproducing conditions that a well sees in the fields and we analyze the data exactly the same way as we do when we apply rate transient analysis to well data. So it's really what we view as a link between the laboratory and the field so that should be of interest to reservoir engineers that have a background in rate and pressure transient analysis.
In Case Study 2, we apply various techniques for core analysis and specifically cuttings analysis for "EvaluatingReservoir Quality and Forecasted Production Variability along a Multi-Fractured Horizontal Well". So trying to understand how reservoir quality and completion quality vary along a lateral by integrating cuttings analysis with logs and drilling data.
And then finally, Case Study 3 is called "Impact of Entrained Hydrocarbon and Organic Matter Components on Reservoir Quality of Organic-Rich Shales - A Duvernay Case Study". So here we evaluate very importantly the impact that organic matter components have on petrophysical properties such as porosity and permeability, etc. And we'll lead up to that particular case study with the discussion of organic matter characterization.

04. Introduction

All right, so moving into the introduction part of this course, I'm first going to present a few facts to you regarding unconventional reservoirs. And the first fact is that when a producing well is completed in these very low-permeability reservoirs, a complex series of processes occur at multiple scales that are initiated by production of a well that we don't completely understand.
And so to give you just a simple example here, I'm showing you a conceptual model of a multi-fractured horizontal well completed in a low-permeability or shale reservoir. And you can see here we have some complex fractures that have been created along the length of the horizontal well. So we're just showing one section of that. And as we know, an objective today is to initiate many, many fractures along a horizontal well. And so I want to focus your attention on the interaction... I'm just going to move my coffee out of the way, the interaction or the intersection of a fracture and the reservoir. And so what we do when we start production of a well for a particular stage, that initiates a pressure transient that moves out into the reservoir. And we can see that that triggers a series of processes that occur at finer and finer scales. So we're just going to zoom in on that little red box, this one here just for emphasis, to show you what happens when we start to produce a well.

05. Introduction - 2

So at the macro scale or the meter scale, we first initiate production through induced fractures, hydraulic fractures and reactivated natural fractures. And that triggers processes that occur at finer and finer scales all the way down to the nanometer scale. And so when one is performing characterization of unconventional reservoirs, we need to understand these different processes that could occur at different scales and target our characterization methods to evaluate properties that control these processes, storage and flow in the reservoir.

06. Introduction - 3

So for this particular course, I want to place in context the scales that we're going to be looking at. So at the macro scale, that's really the domain of RTA and PTA, right. So we're looking at flow through induced fractures through natural fractures. In this course, we're going to focus on processes and characterization methods that apply from what we call the meso-scale down to the nano-scale.
So at the meso-scale, we're talking about looking at core and describing core looking at the fabrics of core really at the kind of the millimeter scale, centimeter to millimeter scale that controls flow at that level.
And then as you can see, when we get into the micro- and nano-scale, we're starting to look at processes that occur at the sub-micron scale. So what I've shown you here are some SEM (scanning electron microscope) images, for example, that highlight fabrics of the rock that control flow at that scale. And then when we get into the nano-scale, that's where we need special imaging techniques like scanning electron microscopy and transmission electron microscopy to really observe what's going on at that scale. So again, this course will focus on characterization of cores and reservoir samples in general that try to capture the physics of what's going on at the meso- to nano-scale.

07. Introduction - 4

All right, to emphasize this point of scale dependance a little bit further, what I'm showing you here is a diagram (this is courtesy of Nisael Solano, who's a former Ph.D. student in our group) that shows you characterization methods really as a function of scale. So along the bottom here, we're showing you relative scales from the very small scale to the very large scale. And along the y-axis here, we're showing you various characterization methods that can be applied to these different scales. So at the very large scale here up at the kilometer to 100s of meter scale, we're talking about techniques such as seismic surveys, well testing, outcrop studies, etc.. In this class, this course in particular, we're going to focus on core analysis. And you can see here we can apply a variety of different characterization methods that allow us to characterize properties from, say, the meter scale all the way down to the nano-scale. So several of these methods we'll talk about in the class. So we'll discuss very briefly X-ray CT andMicro CT, which can be used to image rocks and allow us to characterize fabrics at those scales. And then zooming in a little bit further, optical microscopy, scanning electron microscopy and transmission electron microscopy allow us to visualize and image fabrics of the rock pores, etc. down to the nanometer scale. We'll also talk about methods such as low-pressure adsorption using nitrogen and CO₂ gas, which can allow us to characterize pore size distributions and internal surface areas of rocks. And then finally, we'll also, in our discussion of porosity, talk about the use of helium pycnometry and mercury intrusion, a combination of which allows us to get porosity estimates. So again, I want to emphasize the scale dependance and we'll focus in this course on the techniques that are captured in the red dashed box there.

08. Introduction - 5

All right, moving on to some additional facts. We know that reservoir characterization methods that account for the appropriate physics are in their infancy. So when I talk about this, I mean things like pore confinement effects. So pore confinement effects are an artifact of the fact that we have very small pores down to the nanometer scale and that causes us to have somewhat unusual gas storage mechanisms such as adsorption. We can see that the PVT properties of fluids are altered at this scale. It affects flow. So deviations from Darcy flow, such as gas slippage and diffusion, are really a result of pore confinement effects. And as we go through this course, we'll talk about how we can account for that and take that into consideration in core analysis.
Multiphase flow, that's a big one. Today, of course, when we're producing unconventional reservoirs, often producing either oil or liquids rich gas reservoirs, where we can see hydrocarbon liquids and gas flowing along with water to a well. So we have to develop characterization methods that allow us to capture those effects. And in this course, we'll talk about characterizing multiphase flow using relative permeability techniques, for example.
And then lastly, this idea that when we create hydraulic fractures and in shales, we can induce a complex fracture network. So we may have propped hydraulic fractures along with unpropped induced fractures in the reservoir. And as you'll see, we have methods that we've developed in the laboratory to measure permeability and compressibility in both propped and unpropped fractures that allows us to use that information directly for RTA models and for reservoir simulation. So various other things that we'll also talk about in this course.
So at a high level, understanding how to advance characterization methods is really critical for sustainable development of unconventional reservoirs through primary and enhanced recovery processes. And as you'll see and I'll try to highlight as we go through, a lot of what we'll be talking about in this particular course can be applied to more sustainable energy concepts such as carbon capture and storage and hydrogen production. So I'll be sure to try to highlight that as we go through.

09. Introduction - 6

Now this slide is courtesy of Dr. Ghanizadeh and it emphasizes that when we're doing core analysis, we have to develop workflows depending on what we're trying to study in the rock. So these workflows are vital to help us understand processes that are occurring at the core scale. So in this course, we'll talk about several different workflows that are related to multiphase flow, fluid rock interaction, geomechanics and geochemistry. And so you can see here, I've listed a few different characterization techniques under each particular workflow that we'll go through in detail once we get to that subject matter. And as we'll see, depending on the reservoir type, we may need to integrate these different workflows to come up with a complete characterization of the rock that helps our development either using standard techniques or enhanced recovery techniques as well.

10. Course Learning Objectives

All right, so with that basic introduction behind us, we can now have a discussion of our learning objectives. So by the end of this particular course, I'm hoping that participants will be first familiar with the application of routine experimental methods, i.e. those methods that are commonly applied by commercial laboratories and the theory to unconventional tightcore analysis and be able to discuss both advantages and disadvantages of these techniques. None of these techniques are perfect. They have limitations, but it's important to understand what those limitations are so when you err, you have an idea of which direction that error is occurring.
I'd like the participants to be familiar with the recent advances in special core analysis methods as applied to unconventional reservoirs. This is a highly evolving area. We're learning every day how to properly characterize things such as multiphase flow gas injection into unconventional reservoirs. So I try to provide some cutting edge research in this section of the course to keep you updated on what's going on.
I want the participants to understand how to derive petrophysical, geochemical, and geomechanical properties from both core samples and drillcuttings. So the course title is Tight Core Analysis but generally speaking, we'll talk about not just core, but reservoir samples in general and specifically drill cuttings, because drill cuttings are commonly the only reservoir sample that we have available to us when we drill these long horizontal wells. So we'll spend a bit of time on drill cuttings.
And then lastly, I'm hoping that the participants will be conversant with a rigorous workflow progressing from nondestructive to more destructive analysis methods for the analysis of unconventional or tight core and reservoir samples.
So that's it for this particular lesson. In the next lesson, we'll cover 2 very important workflows, including a field development workflow that places in context the core analysis work that we'll learn about. And then we'll also talk about a workflow that we've developed within Tight Oil Consortium for routine core analysis so stay tuned for that.
Clarkson, C. R. "Nanopores to megafractures: Current challenges and methods for shale gas reservoir and hydraulic fracture characterization." JNGSE 31 (2016): 612-657."Clarkson, Christopher R., and Nisael A. Solano. "Combined use of neutron-scattering, fluid-invasion, and image-analysis techniques to assess pore structure, accessibility, and connectivity in tight rock." (2016).Clarkson, C. R., C. L. Jordan, D. Ilk, and T. A. Blasingame. "Rate-transient analysis of 2-phase (gas+ water) CBM wells." Journal of Natural Gas Science and Engineering 8 (2012): 106-120.