Abstract
Current workflows in petrophysics ignore the impact of stress on both the compressional and shear sonic velocities. Neither the Wyllie time average equation nor the Raymer-Hunt-Gardner equation have an explicit stress dependence. However, most laboratory measurements on recovered core show substantial changes in both compressional and shear velocities due to variations in stress loading. This inconsistency has led to the current situation where dipole sonic integration is qualitative in both petrophysics and geomechanics. In this talk, I will present and explain a new method to integrate dipole sonic velocities in quantitative petrophysics that accounts for the depth-dependent variations in stress.
This new method quantifies the influence of porosity, mineralogy, and fluids, while isolating and quantifying the added influence of stress. Velocity variations due to changes in petrophysical properties are determined using a multi-mineral petrophysical solver. A matrix and fluid substitution workflow is then used to normalize the velocities to an idealized formation with constant petrophysical properties with depth. The petrophysicist then uses the normalized velocities to diagnose and quantify the depth-dependent stress effect. Once the depth-dependent stress effect is determined, the petrophysicist removes the stress effect from the original sonic data yielding improved sonic curves for use in petrophysics. In addition, the petrophysicist gains new insight into the geomechanics for both the target reservoir and adjacent layers.
I will present a case study showing how to implement this workflow into current practice. I will highlight the improvements gained in both the petrophysical and geomechanical analysis. The audience will clearly see how this new workflow places the petrophysicist in a unique position to influence both drilling and completion decisions in their organization.
Speaker Biography
Tom Bratton is a consultant to the oil and gas industry specializing in geoscience applications for engineering operations. After retiring from a 36-year career with Schlumberger, he was a Visiting Professor and Research Associate in the Petroleum Engineering Department at Colorado School of Mines (CSM). While at CSM, he enrolled as a graduate student and earned his PhD in Geophysics. Before starting his consulting business, Tom was a scientific advisor to Schlumberger’s senior management, specializing in petrophysics, geophysics, and geomechanics with a broad base of experience in drilling, completion, and reservoir engineering. Tom is a full member of the Society of Petroleum Engineers (SPE), Society of Petrophysicists and Well Log Analysts (SPWLA), Society of Exploration Geophysicists (SEG), European Association of Geoscientists and Engineers (EAGE), and the American Rock Mechanics Association (ARMA).
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When
Tuesday, December 15, 2020
11:00 am - 12:00 pm
Cost
At this time we are not going to charge anything for these webinars. We reserve the right to change this in the future.
Webinar reservation: 
Next Month's Talk
Determining Water-Filled Porosity of Tight Oil Reservoirs with a New Interpretation Method for Dielectric Dispersion Measurements
Nikita Seleznev
Schlumberger
SPWLA Distinguished Speaker
Forward this newsletter to a friend to invite them to the webinar.
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From the Editor
Dominic Holmes
We are going virtual with the annual DWLS holiday party, holding it via webinar. This event will be held like a chat room, so that all guests will be able to see and speak with each other. Bring your festive spirit and favorite beverage to hear our guest speaker (TBA) and “see” all your colleagues. It will be held Tuesday December 8th at 4pm. Click here to register for the event.
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From the President
Yulia Faulkner
Dear DWLS Members, Families and Friends,
“I believe, I believe, it’s silly but I believe” – Miracle on 34th street
As we approach the end of the 2020 DWLS year I want to thank all the Board members for their hard work toward making this year as successful as it could be. I truly appreciate all that you have done this past year, thank you for your commitment, your drive, and your energy. I also would like to thank all our DWLS members for their continuous support, for our very successful Web-Based Season, which started in September.
I find that the holiday season is a natural time to pause and reflect upon the year, focus on what really matters. Needless to say that 2020 has been challenging for all of us, with tighter restrictions around COVID, this holiday season will be different, and I encourage all of you to please keep in touch with family, friends, those who have lost their jobs. Connect, encourage, support, be there for one another, we might not have it all figured out, and we might not know what the future holds but we have each other this holiday season.
This month of December marks my 15 years anniversary of working in oil and gas industry. And while I do not have the most years in oil and gas, I can agree that 2020 was one of the hardest years in our industry and I am sure everybody felt that way. Nobody knows what 2021 holds, but I do believe 2021 will bring positive changes that we all need.
With the holidays not too far away, I would like to wish everyone a great holiday season. Please share our best wishes with families and friends and stay tuned for updates on upcoming 2021 luncheons and workshops.
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From the VP - Membership
Rich Whittington
Final reminder for those members who are not lifetime members. Please renew your membership for next year. You can do this on our homepage. The cost is only $10/year or sign up for the lifetime membership for $75. Looking forward to 2021!
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Calendar of Events
Click the calendar to the right to view events on the web.
Other Important Events
2021 SPWLA Annual Symposium, May 15-19, 2021 (Boston,MA) - Note this will be held virtually
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DWLS Sponsors
Click here to view the sponsors on the website, or click on any image to contact a sponsor.
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Chapter Statistics
Statistic
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This Year
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3-Year Average
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| # of Active members * |
282 |
348 |
| # that are New members0 |
0 |
15 |
| # that are Students * |
7 |
7 |
| # that are Lifetime Members * |
264 |
263 |
| September luncheon meeting attendance |
49 |
48 |
| October luncheon meeting attendance |
31 |
37 |
| November luncheon meeting attendance |
42 |
32 |
| Holiday party attendance |
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21 |
| January luncheon meeting attendance |
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48 |
| February luncheon meeting attendance |
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60 |
| March luncheon meeting attendance |
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35** |
| April luncheon meeting attendance |
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29** |
| May luncheon meeting attendance |
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64 |
* Note that we did a thorough cleanup of bad email addresses that resulted in some of our members being removed until they can be tracked down again. So this year's membership numbers are going to be a bit lower.
** These numbers are skewed due to COVID-19 luncheon cancellations.
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The DWLS Newsletter is published monthly September through June by the Denver Well Logging Society. For information on membership or advertising, contact the editor. For other inquiries, contact a member of the Board of Directors.
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