1 - Introduction

1.01 - Elements Of Reservoir Geochemistry (10 min.) Sample Lesson
1.02 - Reservoir Characterization & Monitoring Over A Well’s Lifecycle (7 min.)
1.03 - Geochemical Fingerprinting Of Fluids (17 min.) Quiz: 1.03 - Geochemical Fingerprinting Of Fluids

2 - Overview of Fluid Chemistry & Reservoir Geochemistry Principles

2.01 - Types Of Fluids (Oil, Gas and Water; Phase, Chemistry) (24 min.)
2.02 - Fluid Chemistry Considerations (14 min.)
2.03 - Program Design And Limitations Of Each Fluid Type (21 min.)
2.04 - Application Of Reservoir Geochemistry To Field Development (24 min.)
2.05 - Geochemical Program Design (14 min.) Quiz: 2.05 - Geochemical Program Design

3 - Reservoir Geochemistry Workflow

3.01 - Fluid Characterization To Identify End Members (8 min.)
3.02 - Migrated Fluids And Their Mixing (18 min.)
3.03 - Statistical Tools And Software (21 min.) Quiz: 3.03 - Statistical Tools And Software

4 - Reservoir Appraisal

4.01 - Fluid Phase – Anomalous GOR (18 min.)
4.02 - Fluid Property Prediction (API Gravity And Viscosity) (28 min.)
4.03 - Biodegraded Oil, Compositional Gradient (10 min.) Quiz: 4.03 - Biodegraded Oil, Compositional Gradient

5 - Production Allocation

5.01 - Production Monitoring Vs. Allocation (24 min.)
5.02 - Origin Of Stray Gas (17 min.) Quiz: 5.02 - Origin Of Stray Gas

6 - Flow Assurance

6.01 - High Molecular Weight Waxes, Asphaltenes (18 min.)
6.02 - Source of H2S (20 min.) Quiz: 6.02 - Source of H2S

7 - Monitoring EOR

7.01 - Waterflood Operations (18 min.)
7.02 - EOR-EGR, CO2-EOR, WAG (17 min.) Quiz: 7.02 - EOR-EGR, CO2-EOR, WAG

8 - Maximizing Recovery

8.01 - Maximizing Recovery With Geochemistry (12 min.) Quiz: 8.01 - Maximizing Recovery With Geochemistry

Optimizing Field Development Using Natural Fluid Tracers / 1 - Introduction

Lesson 1.01 - Elements Of Reservoir Geochemistry

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Transcript

01. Lesson 1.01: Elements Of Reservoir Geochemistry 02. Turning Existing Resources into Reserves 03. Aspects of Petroleum Recovery Informed by Geochemistry 04. Reservoir Characterization & Monitoring over a Well’s Lifecycle

01. Lesson 1.01: Elements Of Reservoir Geochemistry

I'm Jennifer Adams and welcome to Optimizing Field Development using Natural Fluid Tracers. There are all sorts of ways to improve your production in the oil and gas industry, and many of the tools that I often, am asked to use involve using natural fluid tracers, different chemical compounds found in oil, water, and gas. The same methods and principles can be applied to environmental studies as well. However, the use of "geochemistry" is often considered challenging or fraught with difficulty in the oil and gas business. The results are sometimes not portrayed clearly enough, and the deliverables seem tangential to what the actual engineers are needing. England puts it this way: "It is unusual for geochemical measurements like GC fingerprints, isotope, and biomarker ratios to be of any direct interest to reservoir and production engineers. However, the interpretations that can be made from geochemical measurements are of crucial interest and have a large impact when translated into cost and production forecasts which are usable by engineers". Today, I will take you through a full suite of different methods and applications, using fluid chemistry of all sorts to try and solve some typical problems that we find in the oil and gas industry. And as I said, they're easily translatable into environmental applications or the current efforts in carbon capture and sequestration.

02. Turning Existing Resources into Reserves

So, how do we really turn existing resources into reserves? And how can naturally occurring geochemical tracers reduce operators' costs by improving reservoir appraisal, monitoring production, and diagnosing different production issues? Well, this field is called reservoir geochemistry. And it's been a long around for many decades. The definition of reservoir fluid geochemistry is the measurement and application of compositional variations in subsurface reservoir fluids that can be oil, water, or gas to the solution of practical problems in the energy and environment sector. You can think about it this way. There are over 100,000 natural tracers in black oil, and about 12-20 in natural gas, and a few more than that in water. And these natural tracers can be used to assess reservoir continuity. That means identifying compartments, barriers, or baffles, looking at transmissibility of faults, and how that might correlate to different fluid properties. It's also possible to do production allocation, i.e. figure out where the produced fluids have actually come from in the subsurface. A cousin of production allocation would be identifying contamination. You may have frac pond at surface which may be contaminating local aquifer water. You also might use the same technology to identify how much mud contamination is found in your subsurface wireline fluidsamples. Another option is to use this sort of technology to diagnose different mechanical problems. Anything from validating surface meter data to diagnosing casing or tubing leaks. This also, the same technology can be used when looking for stray gas. Gas found in residential basements in fact, can be typed and correlated back to its source. And finally, environmental monitoring has many applications using reservoir geochemistry. You can distinguish natural seeps from development-related releases. Carbon capture operation monitoring is critical. And then you can simply do standard monitoring for regulatory purposes. The principles of reservoir geochemistry are relatively simple and they have wide applications. The other nice thing about reservoir geochemistry is that normally it's relatively inexpensive compared to doing additional seismic monitoring, drilling new wells, even building very large models. Sometimes reservoir geochemistry is relatively cheap and quick.

03. Aspects of Petroleum Recovery Informed by Geochemistry

So, here's just a list of some of the aspects of petroleum recovery that are informed by geochemistry. Estimating reserves, basically figuring out how much petroleum is present and recoverable in the subsurface. You may want to determine fluid quality. What is the value of your produced petroleum and how does that vary over time? Fluid quality, we often want to know before we do the completion on a well, so pre-drill or pre-completion fluid quality. Recovery efficiency also might be of interest. How much fluid can you recover from a particular reservoir? Have we adequately drained the whole resource or is there potential for secondary or tertiary recovery operations? In this one, you also might want to understand whether there are wells that are interacting in terms of their production and whether you need to change the well spacing. Estimates of unwanted fluids for disposal, how much water you actually going to produce? Where is that water coming from? Is there a particular thief zone in your reservoir you need to cauterize? Also, is there an abundance of non-hydrocarbon gas being produced? Is it possible to cut off that flow stream? Flow assurance is a major issue once the wells are drilled and completed. How can you minimize downtime and deterioration of the infrastructure related to corrosion possibly or formation damage? And then reservoir quality and fluid quality are also impacted simply by flowing of fluids, possibly different types of operations, workovers, or injection. And then, as I mentioned, viability and monitoring of enhanced recovery. Are there secondary or tertiary recovery options that are viable? And will they recover sufficient fluid to make them financially viable?

04. Reservoir Characterization & Monitoring over a Well’s Lifecycle

Now we'll look at how different reservoir characterization tools can be used over the full life cycle of a well. Of course, you have many tools in your toolbox all the way from regional seismic through pressure monitoring down into your petrophysics and flow assurance. These different tools, of course, apply at different parts of the life cycle. Regional seismic might be employed early on in life cycle when you're doing early exploration and may be employed a little bit later for seismic monitoring. Whereas reservoir quality features fairly heavily during early drilling of new wells and then tapers off during full-field development. What's interesting about geochemistry, which is the topic today, is that it is employed all the way from the point of early exploration through appraisal, full-field development into tertiary recovery, and finally into decommissioning. And even after the well is decommissioned, we sometimes monitor casing gas to make sure that there are no leaks coming out of that decommissioned well. In terms of geochemistry, early on you'd be looking at fluid quality distribution during exploration and understanding of the prospect and its extent. And then you might move in through appraisal into production allocation. And later once you start tertiary recovery, monitoring miscible floods, for instance. In terms of production monitoring, optimized completions and mechanical issues may feature partway along through appraisal and full-field development which can be informed by reservoir geochemical methods as well as microbial remediation. If you seem to be having some kind of souring issue or other microbial activity. In terms of flow assurance, geochemistry sometimes features in asphaltene deposition prediction, wax, especially heavy waxes, any kind of mineral scale as well as reservoir souring. So, there are several, entry points into the lifecycle of an oilfield with regards to geochemical applications. And you can also look at compartment mapping. And lastly, reactive transport modeling may feature as you get into a full-field development environment. And geochemical parameters are often used to calibrate those to ensure that you understand the full recovery extent.
England, W. A. "Reservoir geochemistry—A reservoir engineering perspective." Journal of Petroleum Science and Engineering 58, no. 3-4 (2007): 344-354.