From the President

Dick Merkel
EnCana

Log data quality over Paleozoic reservoirs in the Rocky Mountains has always been problematic. Borehole conditions often cause tool sticking and/or washouts that exceed tool measurement compensation and environmental correction calculations. As a result, the development of robust petrophysical models in our region has suffered. All too often, when looking at the log data, I am reminded of my father's advice in avoiding "making a silk purse out of a sow's ear". Unfortunately, that is often what is expected of us on a daily basis.

It is in the best interest of both the operating and service companies to obtain the best quality data as possible. Since the DWLS is the primary group dedicated to the advancement of petrophysics in the Rocky Mountain area, we should take it upon ourselves to communicate problems and solutions with quality control not only within our respective organizations but also among ourselves. Without this interaction, we could find ourselves reverting back to perforating off a cased-hole GR, which benefits nobody except the perforating companies.  

From the Vice President - Technology

Jack Bowler
Bowler Petrophysics, Inc.

Here's a list of the upcoming talks.  Don't forget to put them on your 2008 calendars!

From the Vice President - Membership

Bill Rodgers
Weatherford International

Latest Membership Numbers

Lifetime = 73
Annual = 46
New = 50
Student = 14
Total Active Members = 183

We also have 18 members that have not renewed their membership for the 2007-2008 year that were active last year. After the December meeting, these members will no longer be receiving the newsletter or notice of the upcoming meeting.

If you do receive the notice in January 2008, or have not been receiving it since August, you either have not paid your annual $10 dues, or there is a mistake in the membership list. Please let me know about any mistakes.

I encourage all members to encourage all geoscience professionals that you know to join the Denver Well Log Society. We are enjoying really great presentations. Of course, it's a great networking opportunity. Don't forget. New members pay no dues until September of 2008. In fact, new members can email me your membership form (or the information we are requesting), without taking the time to mail a letter. So take 5 minutes, download the form (membership form) and send me an email mailto:bill.rodgers@weatherford.com) today.

If you are already a member and, just send your $10 check with your business card to me.

Here's a membership form you can fill out and send with your payment to me at:

Bill Rodgers
DWLS VP Membership
c/o Weatherford International
410 17th St, Suite 400
Denver, CO 80202
mailto:bill.rodgers@weatherford.com

Or bring your filled out form along with payment to the September meeting.

If you are already a lifetime member, you may want to fill out an update form if any of your contact information may have changed in the last year.

"Design Of A Sliding-Weight Borehole Gravimeter To Measure Rock Density In Highly Deviated And Narrow Bore Holes"

Max Peeters

Conventional borehole density instruments measure only 30 cm away from the borehole, while gravimeters look up to 300 ft away, with a vertical resolution of less than 10 ft. They match vertical seismic profiling in resolution and coverage of a significant part of the reservoir. Borehole gravimeters using Lacoste-Romberg spring sensors are available, but their use is limited due to large tool diameters, and restricted to near vertical holes. Tool diameters less than 2" are mandatory for cased hole & production logging. Some surface gravimeters use a weight that falls inside a vacuum tube, which has to be positioned perfectly vertical, and this method has therefore not been used in boreholes. 

This paper describes the design of a tilted sliding-weight instrument that overcomes these limitations, and reviews algorithms required to determine the density in deviated boreholes. All measurements including tilt, travel time and travel distances of the sliding weight have to be made with an accuracy of 1 in 108. This is achieved by using accurate tilt-meters for the angle, atomic clocks for time, and an interferometer to measure the distances. By subtracting the up and down going paths of the sliding weight, zeroed around the top of its trajectory, the effect of the friction is eliminated. This also accounts for gas friction, and relaxes the vacuum quality of the tube, thereby removing an ion-pump, which would not fit into a borehole. A tool based on this design is expected to resolve reservoir management questions such as whether gas close to a borehole came out of solution, or is part of a secondary gas caps. Moreover, combined with through casing resistivity it would allow saturation calculations and flood front monitoring in a reservoir volume more than 1000 times larger than is possible with current techniques.

About the Speaker

Max Peeters is currently teaching Petrophysical Courses for Petro-Skills; he is also the Honorary consul for The Netherlands in Denver, and assistant Park Ranger. Before that he was professor of Borehole Geophysics and Petrophysics at the Colorado School of Mines and holder of the Distinguished Baker Hughes Chair from 1998 to 2007. From 1992 to 1998 he was professor of Petrophysics at the University of Technology in Delft, and Petrophysical Adviser at Shell Research, both in The Netherlands.  Peeters received a MSc in Physics of Delft University of Technology in 1968, followed by two years lecturing at the Royal Dutch Navy Academy. In 1970 he joined Shell International, and worked as Petroleum Engineer and Chief Petrophysicist in Australia, England, Brunei, and California. In 1988 he returned to The Netherlands where he was in charge of Shell's global Formation Evaluation team, and headed a Petroleum Engineering team for the development of business opportunities in the former Soviet Union.  Max Peeters founded and directed the Center for Petrophysics at the Colorado School of Mines and is is one of the editors of the Petroleum Geoscience and Geophysical Prospecting Journals. In June 1996 he received the Distinguished Technical Achievement Award from the Society of Professional Well Log Analysts (SPWLA), and in 2003 a Technical Advancement Award from the Colorado School of Mines. Max Peeters was a visiting professor at Curtin University in Perth Australia in the fall of 2002, and a distinguished lecturer for the SPWLA in 2002-2003. He has published over 20 papers on petrophysical subjects, and holds two patents for wireline logging tools.