Title: Summary of the RMAG/DGS 11th Annual 3-D Seismic Symposium
Author: Ron Pritchett
Publication: The Outcrop, May 2005, p. 29-32
The Rocky Mountain Association of Geologists (RMAG) and the Denver Geophysical Society (DGS) delivered another valuable event March 11, 2005, with the 11th Annual 3-D Seismic Symposium held at the Denver Downtown Marriott Hotel.
580 people registered for this one-day event, a capacity crowd. The meeting is a popular annual event because; 1) quality presentation of useful information, insights to workflows, and cutting-edge geophysical applications; 2) the meeting is a gathering of talent in the geo-professional community; 3) the meeting falls on a Friday, and 4) registration is relatively low-cost. The symposium is designed to blend selected case-history talks on geophysical and geological applications in North America from industry and research leaders, together with a networking opportunity for geo-professionals, and includes a book of abstracts of contemporary findings in applied geophysics. In recent years – the boom times – the meeting has evolved to a celebration for industry “survivors” who compare and contrast current trends in lively discussions.
This year, kickoff-speaker Robert P. Peebler (President and CEO of Input/Output, Inc.) expressed a theme running through the conference – the challenge to professionals who integrate abundant geophysical technology in corporations that compete in securities markets.
The technical march is from 2D-to-3D-to-Full Wave analysis. Problems facing geo-professionals and managers are both human and technical in adapting to the changes. To boost perceived stock value, Peebler noted that oil and gas companies recently spent as much or more on stock repurchase as on reserve replacement. Peebler suggests that National Oil Companies are currently the leaders in pushing leading edge technologies for Full Wave analysis – what will this mean for future USA energy supplies?
Imagine drilling through more than 400 feet of oil-saturated sandstone at less than 7,000 feet depth, onshore USA (central Utah thrust belt, Sevier County). Since completion in May, 2004, the #17-1 Kings Meadow Ranch and its confirmation well have produced more than 250,000 barrels of 40-gravity (API) oil from the Jurassic Navajo sandstone. The fluid trap is an overlying Arapien salt-section. A closed structure – 10 miles long and 4 miles wide – awaits development for recovery of more than 800 million BO, according to the operator, Wolverine Gas and Oil of Grand Rapids, Michigan. Thus the Covenant Field discovery was described by Keith R. Johnson (Geophysical Manager – Wolverine). 3-D seismic plans are under way to delineate structures on Wolverine’s 65,000 acre unit, though drilling the discovery was justified from 2-D seismic, surface geologic mapping, regional geology, gravity residuals, and geochemistry coupled with satellite imagery.
In retrospect, the Covenant Field discovery resulted from the persistence and planning of experienced geoscientists and managers who integrated all available geological-geophysical data, organized the facts and sold the deal. The Kings Meadow Ranch #17-1 well is a recent discovery, though the general geologic structure has been known for many years. The structure was first mapped by C.E. Dutton more than 125 years ago. Chevron controlled key acreage for approximately 50 years, did the early geophysical work, and eventually farmed out to Wolverine. Wolverine exhibited the project twice at NAPE (North American Prospect Expo – Houston), showing the merits of the play to more than 65 companies before finding risk-partners and committing to drill. Significantly, the structural trend extends for more than 100 miles and many more drilling opportunities will be found (a detailed article was published in the Oil and Gas Journal of Jan 17, 2005).
The third speaker was Peter M. Duncan, Ph.D, President and CEO of MicroSeismic, Inc. Peter described a number of applications of “passive” seismic monitoring, including hydraulic fracturing, flow-testing, listening for fault-activity, and tracking water and steam floods. The method is challenged by signal-to-noise data, though Duncan showed examples of how passive seismic methods delineate the patterns of “frac” deformation and directions of principal stress. Linked to the array of dynamic geophysical methods and downhole sensors, passive seismic gives an operator more choices for lowering costs and imaging reservoirs. Beyond petroleum applications are numerous cultural and safety applications in cities and near earthquake hazard zones. Passive seismic monitoring and mapping is an important move for the geophysical industry, toward profits and safety.
The late-morning session touched the practical aspects of obtaining seismic surveys and extracting relevant data from fractured reservoirs of the Western USA. Stuart Wright of Dawson Geophysical described the planning process for a typical 3-D shoot in the West. Seismic activity on federal land depends on permits considering archeology, wildlife, and people who may object to the operations. Opponents of oil and gas development are numerous, well organized, and vocal; workers at the Bureau of Land Management (BLM) may or may not regulate to a constructive end, though operators are not helpless.
Operators can communicate deliberately and proactively. Sending facts and positive messages to regulators and the public are vital components in seismic programs. As Wright said, operators can, “One – plan ahead, two – get it in writing (BLM requirements), and three – talk to the boss (BLM manager).” Wright led by example – he used a mixed-media presentation that kept audience attention. Stuart showed excerpts from a video created by the International Association of Geophysical Contractors (IAGC) – “Low Impact Seismic Exploration: In Search of New Oil and Gas Supplies” – available on CD at the meeting (see http://www.iagc.org).
Mark Wagaman (Veritas DGC) showed how to lower costs and reduce the environmental footprint of 3-D seismic acquisition with the “stakeless” survey. Airborne Light Detection and Ranging (LiDAR) provides advantages such as: minimal public exposure; precise elevation control; more accurate source and location coordinates; and integrating Digital Elevation Models with surface structure. Helicopters, GPS (Global Positioning System) units, and laser surveying are technologies employed to reduce costs compared to traditional stakes and clean-up. 3-D acquisition quality is improved because of more accurate positioning and corrections. Contractors can get in and out with the least disturbance to the land – a big advantage in public relations.
Jim Gaiser, Ph.D (WesternGeco) presented an example from the developing Pinedale anticline of Sublette County, Wyoming. The Upper Cretaceous Lance Formation is faulted and fractured across the anticline at depths between 9,800 to 14,800 feet. Fractures polarize acoustic energy. Using a 3-D array, Gaiser detected S-waves splitting to a fast wave parallel to fractures and a slow wave normal to fractures. Fractures also have a scalar aspect, providing a way to “calibrate” smaller scale FMI (Formation MicroImager) wire line logs with larger-scale 3-D seismic surveys that resolve fracture orientation from velocity differences. At Pinedale, Gaiser found agreement between FMI fracture-finder logs and the fast S-wave direction – a N35W regional anisotropy.
Alistair R. Brown (Consulting Geophysicist – Dallas, Texas) was the keynote speaker. Alistair’s wise advice and distinguished career is evident in his “standard text on methods of 3-D seismic interpretation” featured at the conference – SEG Investigations in Geophysics, No. 9 and AAPG Memoir 42 – Sixth Edition.
Alistair’s talk was titled, “Pitfalls in Modern 3-D Seismic Interpretation.” Technical power in workstations also exposes us to more interpretation error, such as: when windowed amplitude replaces horizon amplitude; when data “character” (phase and polarity groups) are mistied to key reservoirs and traps; when amplitude quality is diminished by “reduced and variable seismic coverage.” People who use workstations must be more than technicians, said Alistair. All who will interpret geophysical data must appreciate ways geophysical attributes relate to real earth models, and think about regional geology in the data to prevent dry holes.
In 2005, the Denver Geophysical Society is 55 years old. At noon during the conference, many past presidents were called forward for a special ceremony celebrating the work, service, and discoveries across the years.
Shallow, Upper Cretaceous Niobrara chalks contain biogenic gas. For one commercial area – Bonny Field of eastern Colorado – authors showed an example of 3-D seismic applied to fault-bounded compartments. Jim Frazier (Fidelity Exploration), Evan Genaud (Kerr McGee), and Ned Sterne (Petro-Hunt) engaged the audience with a team presentation, covering the structure, reservoir engineering, and a geological/geophysical interpretation. Ultimate recovery from the field and trend is expected to be on the order of 600 BCFG from less than 3,000 feet in depth, thus the play is worthy of 3-D seismic and interpretation costs. The team integrated regional geology, describing salt solution as a process that created structural traps for gas. Key isopachs from seismic and well data point the way to gas targets.
The Best Speaker of the Day (by audience vote) was John Logel (Anadarko Canada). John showed useful methods in solving the dolomite resolution problem (low acoustic contrast). Geologic information can be preserved in the data by taking care with a sound geologic model, VSP data, and processing that will de-multiple and preserve amplitude and phase. John demonstrated effective communication skills, too. Few will forget his explanation of attenuation “Q” blending a story about an angry neighbor and music from the Guns and Roses rockers. Dolomite reservoirs represent a very large gas resource in North America, and John showed ways to refine the data for prospect targets.
For years, the 3-D Seismic Symposium planning committee has been searching for coalbed methane applications. In 2005, Ivan Dimitri Marroqin (McGill University, Montreal) showed his work on the Fruitland coals of the San Juan Basin, New Mexico. This 9 TCF cumulative coal-gas field varies in production (in part) due to coal thickness and cleat density. Dimitri linked seismic and curvature attributes to these physical properties, and his methods can be applied to coalgas provinces worldwide.
Murray Roth (Transform Software and Services) summarized his study of the famous Teapot Dome structure of Wyoming. The old field and abundant data set provides an opportunity to apply and combine visualization techniques to many data types. Faults and fractures, for example, were imaged by integrating surface geology, 3-D seismic, Vertical Seismic Profile (VSP), microseismic, FMI log data, and production data.
Operators unlock hydrocarbons from tight matrix and shales deeper in the resource pyramid with induced fracturing. The “frac” operations increase production, yet who knows where induced fractures go? Passive seismic monitoring provides clues to shape, height, and extent of induced fractures. The triple team: Nancy House (EnCana Oil& Gas USA Inc.), Julie Shemeta (Pinnacle Technologies) and Brian Fuller (Sterling Seismic Services, Ltd.) showed how to integrate ¼ millisecond sampling (fiber optic wire line) from microseismic tools, and tiltmeter mapping (surface and downhole) to create 3-D images of a Vertical Seismic Profile. P and S wave splitting and time vs. distance motion plots enable 3-D mapping and a sharper image of where the “frac” goes.
Bob Benson, PhD (Colorado School of Mines) explained a high-resolution study in the Permian Basin — West Pearl Queen Field, Lea County, New Mexico. Using 1,057 sources and 986 receivers (55′ x 55′ bin size) and time lapse (4-D) and multi-component (9-C) receivers, Benson’s team tracked CO2 injection to the Permian Queen Formation. 2,100 tons of CO2 were injected to the formation at 4,500 feet for about two months. The CO2 emplacement was imaged in a P-wave difference volume (before and after injection), proving that induced fluids could be tracked in the target formation. A huge volume of oil remains in the Permian Basin in depleted fields. Predicting induced-fluid movement will be key to successful secondary recovery. Benson shed light on these field-management objectives: tracking injected fluids and injection for CO2 sequestering – and both can be achieved with high-resolution seismic.
The RMAG and DGS receive a healthy financial boost from the annual meeting, due to the generosity of corporate sponsors whose management appreciates the worth of case-history information from 3-D seismic. The meeting is the result of extensive planning through the preceding six months; the office-management staff and volunteer committee members make it happen.