Sunburst Consulting was founded by John Gillespie in 1981 with the goal of providing quality well site geology services in the Great Plains and Rocky Mountain regions. The company was originally based in Denver, Colorado. Initially John worked as a stand-alone well site geologist.

Wayne Freisatz, staff geologist at Jerry Chambers – Oil Producers / Axem Resources, Inc., was an early client of John’s and they found common purpose over dinners at the Roughrider in Medora, North Dakota where coincidentally, John found his future bride, Bernice. Wayne joined forces with John and Bernice in the mid-1980s while Wayne completed his Master’s thesis on the Bakken Formation at the University of North Dakota.

In 1996, the company evolved from a partnership of John, Bernice and Wayne to a Billings, Montana based corporation. The Sunburst Consulting, Inc. partnership expanded in 2006 with the addition of Jim Suydam and Layaka Mann. In 2008 the staff expanded to include its first staff employee, Willie Thomas. At the end of 2009, John and Bernice retired, handing the reins of the company to Wayne. Under Wayne’s watch the company experienced controlled growth in response to the rapid expansion of activity in US oil production. At the time of Wayne’s retirement and handoff to Jim Suydam in mid-2014, Sunburst Consulting Inc. added Chris Belback, Felipe Pimentel and Justin Sommerville as company partners.

Jim Suydam, PhD

Geologist and President

jim-suydam_websiteJim was raised in the oil industry from Alberta to the Gulf Coast. A love for the Rocky Mountain region led him to the University of Wyoming where he received a BS in geology in 1986 and then an MS from Montana State University in 1988. Summers were spent “getting oil on his shoes” as an intern with National Oil Company and Mobil Exploration & Production in Denver. Refusing to re-enter society he pursued doctoral studies at Washington State University, graduating with a PhD in Geology in 1994. Fresh out of school but coming into an industry slump he consulted on several small projects on the Sweetgrass Arch. In a twist of circumstance, Jim spent the next 10 years in retail management for Kinko’s in Billings, Montana. In 2004 he returned to his true vocational love and joined Sunburst Consulting as a contract well site geologist, working wells in the Williston Basin, Utah and Nevada. In 2006 Jim became a managing partner and VP, helping the company grow rapidly with the evolving Bakken Play. On July 1st, 2014 Jim succeeded Wayne Freisatz, retiring founding member, as President of the company.


Jim lives halfway down the Yellowstone River in Billings, Montana. He can be found during spare time casting a fly, playing golf, travelling and spending time with family. He has active membership in: AAPG, GSA, RMAG, MGS, WGA and PAPG.

Justin Sommerville

Executive Vice President Operations


Justin Sommerville was born and raised in northern Virginia. After graduating high school in 1998, he thought it would be a good idea to enlist in the United States Army. After the first day of basic training, he thought it would be a good idea to go to college. Eight years later, he graduated from Virginia Tech with a B.S. in Geosciences; after first honorably completing 4 years as an imagery analyst (at the Army’s insistence). In 2007 headed out west to work as a contract geologist for Sunburst. In 2009 he married Tracy a fellow Sunburst contract hand, their son was born in spring of 2013. His experience includes wells in North Dakota, Montana, and Wyoming, drilling in the Williston, Denver-Julesburg, Powder River, and Wind River Basins. In January 2011 Justin was employed by Sunburst as a Senior Geologist to mentor field geologist from the Billings office. He has since moved on to mentoring Senior Geologists and managing field personnel.

Chris Belback linkedin-button-small

Vice President and Chief Technology Officer

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Chris was born in Warrenton, VA and grew up in the Virginia Beach area. After high school, Chris attended Virginia Tech. After a brief stint in the chemistry department Chris decided he loved rocks and made the best major change that he could. He moved into the illustrious Virginia Tech Geosciences department. Chris graduated in 2003 with a B.S. in Geology then he decided to bum around Blacksburg, VA for a bit and worked as a shift manager at a Taco Bell and also delivered pizzas. This pizza delivery job led him to meet a fellow geologist who got a job as a contract well site geologist for Sunburst Consulting. In March of 2005 Chris made the move to Montana with his future wife to start this line of work as well. In January of 2011, Chris took a job as a Senior Geologist with Sunburst, which put him in the office a bit more, and allowed him more time at home with his wife Mary. Chris is currently working on keeping Sunburst in the forefront of technology and integrating geosteering software into Sunburst’s well site and remote steering systems. In his free time Chris can be seen playing ice hockey or curling, rocking on the guitar, or maybe just hanging out around the house with his and Mary’s first and only child, Cece.

Felipe Pimentel linkedin-button-small

Vice President and Chief Development Officer


A Brazilian by birth, Felipe grew up in Ft. Lauderdale, Florida with his parents and two sisters. While working in retail management and attending school at the University of Florida in Gainesville, he discovered his affinity for geology. After graduating with a B.S. in 2007, he decided to trade beaches, sandals and scorching summers for mountains, hiking boots, and cold winters and moved across the country to Billings, MT to become a well-site geologist. He took the position of Senior Geologist with Sunburst in February 2011 and the position of Chief Development Officer in July 2014. Current duties have him overseeing Williston Basin projects and facilitating the training of well site geologists. His experience includes wells in the Williston, Powder River and DJ Basins. When not working, Felipe can often be found enjoying fine Montana craft beers, live music or the mountains when he’s lucky.

Colin McNamara

Senior Geologist


Colin was born in Covington, LA and was raised in rural southeastern Indiana. At an early age Colin roamed Ordovician age rocks exposed along the Cincinnati Arch, and later pursued a bachelor’s degree in geology at Ball State University. After graduation he expanded his geological experience from road cuts and creek beds, westward, to the complex geology of Montana where he became employed with Sunburst Consulting as a well site geologist in 2007. Several years later, Colin took a job as a Senior Geologist with Sunburst. Most of his field work has been focused on the Bakken and Three Forks plays of the Williston Basin. He enjoys Montana countryside and can be found skiing, playing hockey, mountain biking, hiking and floating rivers on the weekends.

Dallas Murray

Senior Geologist

Dallas Bio Pic

Dallas was born and raised on the coast of Maine in the town of Falmouth (Go Yachtsmen!). After graduating high school in 2003, he attended Virginia Tech, starting out as a chemistry major, before transferring to the Geosciences department. After graduating he drove out west to Billings, Montana to start work as a well site geologist starting in January 2008. In May 2012 Dallas took a position of Senior Field Geologist with Sunburst, and in February 2014 took a position of Senior Geologist. His experience includes wells in the Williston, Denver-Julesburg, and Powder River Basins, with laterals targeting the Middle Bakken, Three forks, Niobrara, Ratcliffe, Parkman, and Turner. In his free time Dallas can usually be found on the golf course, trying out some microbrews, and enjoying the outdoors with his lovely dog, Bel.

Tracy Sommerville

Accounts Supervisor and Secretary/Treasurer

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Tracy is a Montana girl at heart who spent her first 18 years in Eastern Montana before going west for college. She graduated from the University of Montana in Missoula in the spring of 2008 and went to work for Sunburst as a Geosteering Consultant soon thereafter. Later that same year she met her now husband, Justin, on a drilling location and after two more years of well site consulting, she left the field to help out around the office. In the fall of 2013 she took on her current capacity of Accounts Supervisor and Secretary/Treasurer.

When she’s not hanging out with her husband and son she can frequently be found running, playing Billings intramural hockey and soccer, or roaming around the wilds of Montana hiking and hunting.

Willie Thomas

Safety Administrator


Born in San Rafael, California, Willie was on the move at an early age. By the age of two he had settled in Billings, Montana with his parents, and by four he was frequently found thirty or more feet up in any tall tree he could find. By seven, Willie had scaled the rimrocks above town and at ten he was biking to all of the local gravel pits in search of the perfect skipping stone. He attended various Billings public schools, graduating in 1979 from Billings Senior High School. He then attended the University of Montana, where he graduated with a BA in English in the spring of 1985. After college Willie settled down to work at Kinko’s, where he worked for 15 years. Sunburst Consulting’s founder, John Gillespie, recruited him. Sunburst Consulting needed someone with printing industry experience and an editor’s eye to spearhead the production side of the business, so Willie was sent out into the oil patch to learn the business of well-site geology. After six years sitting wells in the Williston, Powder River and DJ basins, he migrated to the office, where he edits, proofs and assembles well evaluations and geology logs. In addition to production, Willie also heads the safety department where he trains new employees in oil field safety and makes sure veteran employees stay focused on safe work practices. Willie spends his free time hanging out with his wife and daughter and occasionally smacking a little white ball around a huge green pasture.

For nearly two years NPE used Sunburst Consulting on 18 of our horizontal wells in the Williston Basin. They did a fine job, provided a high quality of service, experienced well site geologists, and continuity of personnel. I highly recommend Sunburst Consulting and will use their services again when the need arises.

David Skari, Geologist, North Plains Energy, LLC

I have been drilling wells for about 28 years and have worked in many basins and several countries. I have been using Sunburst Consulting on most wells I have drilled in the last three years, and most of those have been horizontal wells. I have never used a wellsite service company that comes close to the quality or professionalism of Sunburst. They have top notch, technically adept employees and good management. Having them onsite is like being there yourself. Their wellsite deliverables and final reports are unsurpassed. I won’t use anyone else on my important wells.

R. Scott McCleery, Sr. Geologist, Petroleum Development Corporation.

I have been using Sunburst for more than 20 years and probably more than 100 wells. Together we’ve seen more than a few miles of vertical and horizontal section. With Sunburst I have always gotten consistent, reliable, and accurate wellsite reporting, analysis, and evaluation. Their people are well trained, well-equipped, and eager to learn what the client wants, and meet their expectations. The Sunburst wellsite reports have evolved to cover all the bases from the most basic well data, expanding to include sample photos, print screens of detail gas shows, horizontal lateral plats and more .The management team, starting with John and Wayne (with new additions), provide senior oversight with many years of comprehensive experience. I always feel my wells are in good hands with Sunburst on the job.

Jerry Mayer, Zavanna/Consulting Geologist

Nance Petroleum and St. Mary Land & Exploration Company have been associated with Sunburst for well over 20 years. We have found them to be extremely conscientious and professional in all regards. Consistent, detailed monitoring at the wellsite and effective communication to our office has been a standard. Staying in target is one the biggest challenges in horizontal drilling today and we have found Sunburst does an exemplary job.

Bob Bachman, Sr. Geologist, St. Mary land & Exploration Co.

The personnel of Sunburst Consulting have been an integral part of our Bakken drilling operations team since the inception of the program in 2007. Sunburst has supplied knowledgable, well trained personnel who have delivered consistent, high quality geosteering and wellsite geological services in support of our efforts. Simply put, they arrive on schedule, their equipment functions, they meld smoothly into our team and their product (logs, communication and EOWR’s) is consistently high quality.

Randal L Billingsley, Chief Geologist, Tracker Resource Development, LLC

Sunburst and your wellsite guys have always done a great job for us and I am happy to write a few sincere lines about their work for us. Drilling horizontal laterals requires a high level of geologic expertise and supervision. The ability to geosteer a drill bit and stay in a 5-foot zone a mile underground is a technological capability that still amazes me. Success is dependent on the MWD technicians, the directional drillers and the geologists making accurate interpretations, all working together. I’ve depended on Sunburst for the past several horizontal wells I’ve drilled. We have a great working relationship and I have confidence in their ability. Their reports and presentations are very professional. They’ve done a good job for us and I wouldn’t hesitate to recommend them.

Pat Lemke, Exploration Geologist, Ballard Petroleum


Oasis Petroleum’s experience with Sunburst for the past two years has been excellent. We have operated fourteen horizontal wells with both Madison and Bakken/Three Forks objectives in Montana and North Dakota with Sunburst providing the geo-consulting services. Their equipment has performed flawlessly and their staff actively participated in all of the critical targeting and navigating decisions. The interpretations from the field are always backed up with solid data and many spirited discussions take place in making critical decisions. We are convinced that their dedication and communication skills with both the office and on location averted many lost days of drilling and sidetracks. We recommend all company geologists spend some time on location with the Sunburst hands. When we do we always come back well impressed with the integration of knowledge and skill that we witness. If you care about the targeting and evaluation of your well you will be pleased to find out how much they care about each wellbore.

Bob Candito, geologist, Oasis Petroleum

You may or may not be aware of the wellsite geoscientists we have used in Bakken from the beginning, but they are interested in taking on more of Marathon’s work if there’s a need. Sunburst Consulting (John Gillespie) has done a great job in monitoring the long (2 mile) laterals and were a part of improving the overall efficiency in reducing drilling days from 60 days/well down to ~20/well. (And the wells have stayed in our skinny little target zone for ~100% of their length.) If you have the need, please contact John at the e-mail address shown in his note. Dave Stone and David Brimberry know John’s team well and can give you additional information about their capabilities.

John Sullivan, Bakken Asset Manager, Marathon

I have used Sunburst Consulting for over 25 years. Their well site work has always been very accurate and thoughtful. They have excelled at the important tasks of sample description and gas detection, but just as importantly, they have been able to relate these data to the well and prospect. Their communication was exemplary; both with the office and the well site team. I can’t imagine who else I would use to guide my lateral wells through the thin and subtle pays in the Williston Basin.

Tom Sperr, geologist, Prima Exploration

Sunburst Consulting has, for more than 20 years, worked on many wells I have been closely involved with in the Williston Basin. I recommend them without reservation, as I have always found their well-site services to be professionally and conscientiously performed.

Ken Altschuld, oil-finder

I have had the pleasure of working on 33 laterals with Sunburst over the past few years. Their geologists are technically proficient, hard-working, and easy to get along with. Long days, late night calls, and a hectic pace never impact the quality or timeliness of their work. As a young geologist fresh out of school, I learned so much from my Sunburst counterparts (e.g., geosteering fundamentals, rig operations, and treating the rig crew to pizza). They were mentors in all aspects of my job.

Kelli Randall, geologist, Haynesville play, Marathon Oil Company

Thanks again for the excellent work! We are really impressed and appreciative of the target proposals at site. We benefit from the scope and detail of the final reports that Sunburst’s geologists provide! We appreciate that you give a dam! We anticipate a long, continuing and beneficial relationship with Sunburst Consulting!

Mike Everts , Sr. Asset Geologist, N.A., Halliburton: Red Technology Alliance