Alan R. Huffman

The future of pore-pressure prediction using geophysical methods

Predrill pressure prediction has historically been done using very simple models and overly simplistic estimates of the earths velocity field. The methods usually incorporate a locally calibrated set of curves for pressure. The advent of the effective stress concept and pressure prediction methods that developed from that concept have led to a much-needed inclusion of fundamental physics into the art of pressure prediction. The use of effective stress methods has become the standard for pressure prediction. This technique has many variants including the Eaton method, the Bowers method, and the Sperry Sun method.

Velocity determination for pore-pressure prediction

Overpressured formations exhibit several of the following properties when compared with a normally pressured section at the same depth (Dutta, 2002): (1) higher porosities, (2) lower bulk densities, (3) lower effective stresses, (4) higher temperatures, (5) lower interval velocities, and (6) higher Poissons ratios.

The petrophysical basis for shallow-water flow prediction using multicomponent seismic data

Physical properties of shallow-water flow (SWF) sands differ from most reservoir and seal rocks studied for petroleum purposes. These materials exist near the transition zone between rocks and sediments. Our investigations, the subject of this article, suggest that physical properties of SWF sands are amenable to a prediction methodology that uses high-resolution multicomponent seismic data. SWF sands are a primary hazard to deepwater drilling operations in the Gulf of Mexico. They have the potential to result in well failures and significant discharges of subsurface fluids into the ocean. However, at present, most operators make only a modest attempt to identify SWF before drilling. They drill through these hazards and mitigate any resulting damage at significant expense if one is encountered. This is not rare. According to a report from Fugro Geoservices, approximately 70% of all deepwater wells have experienced SWF. A method for predrill delineation of sands that are close to failure, and thus likely to exhibit SWF, would be advantageous in selecting optimal drilling locations and in developing cost-effective well plans. The current method of identifying SWF involves predrill hazard studies utilizing conventional and high-resolution seismic data to identify zones that might produce SWF. However, the high incidence of SWF mitigation events in deepwater wells shows that existing techniques do not provide adequate resolution or accuracy. At present, no robust seismic method exists for accurately identifying and characterizing SWF. Operators do not have the option to avoid the hazard instead of mitigating the problem after it has started. A new method is required that will permit operators to identify the hazard before the well is drilled. Using seismic data for accurate understanding of the physical properties and deformational behavior of SWF sands is essential to characterization, prediction, and interpretation of these stratigraphic units. To date, very few core and …

Pressure Regimes in Sedimentary Basins and Their Prediction

Recognizing that pore pressure and pressure regimes are critical in the evolution of hydrocarbon provinces, geologists and drilling engineers joined forces to bring you new technology in this publication. The original publication was an outgrowth of an international forum sponsored by the Houston chapter of the American Association of Drilling Engineers. Experts in pore-pressure prediction from the geologic, geophysical, reservoir, and drilling communities were brought together to share the state of the art from each discipline. This product will interest pore-pressure interpreters, basin modelers, explorationists, drilling engineers, and rock physicists.

Recent Advances in Pore Pressure Prediction in Complex Geologic Environments

Pre-drill pressure prediction using geophysical data and methods has historically been done using very simple models and has been restricted by overly simplistic estimates of the Earth’s velocity field. Geopressure prediction techniques have started incorporating more sophisticated velocity methods such as AVO-based phase mismatch algorithms, tomography and pre-stack inversion. These technologies allow the geophysicist to obtain higher resolution estimates of the velocity field in the subsurface that can significantly improve the results of pressure prediction. These technologies permit more robust analysis of P-wave velocities in the presence of contamination from hydrocarbon effects and non-clastic rocks that have been a problem in the past.

Hydrocarbon Prospecting in Deepwater Trinidad Using AVO and Spectral Decomposition

Synthetic models for different fluid types and saturations indicate that fluid prediction is possible with these methods.

Summary of AADE forum: Pressure regimes in sedimentary basins and their prediction

The American Association of Drilling Engineers hosted the forum “Pressure Regimes in Sedimentary Basins and their Prediction” on 2–4 September 1998 at Del Lago Resort in Texas (a few miles from Houston). The meeting (sponsored by Conoco, the U.S. Department of Energy, the Gas Research Institute, Mobil, and Chevron) attracted 159 delegates from 14 countries. They represented 25 operating companies, 10 service companies, 5 drilling contractors, 15 universities and industry research laboratories, and 4 government agencies (U.S. and Canadian). The approximate balance of geologists, geophysicists, and engineers in the audience emphasized the multidisciplinary nature of the subject.

SEG-sponsored sessions at OTC 2001

SEG and the 12 other professional societies which sponsor the annual Offshore Technology Conference in Houston, Texas, have constantly worked, since first organizing this event in 1969, to focus the technical program on major field developments and technological innovations. These efforts have generally been successful—the proof being OTCs longstanding status as one of the premier events on the calendar for many earth scientists associated with the oil industry.

What technologies will impact deepwater appraisal and development 10 years from now

Prognosticating the future in our industry is problematic at best and totally maddening and futile at worst. However, assessing what the trends of the future will be is critical to our success as an industry, and especially to our success in technology development. The range of technologies that our industry employs and will employ in deepwater operations is vast and impossible to cover in the space provided. However, I would like to glimpse at some technologies that will probably have significant impact on deepwater appraisal and development (A&D) in the coming years.

Impacts versus terrestrial processes: Separating fact from fiction

Publication of alternative views to the prevailing ideas in scientific literature is a worthwhile endeavor. However, the article “An introduction to the meteor impact process” (TLE, March 1994) was far more than an alternative scientific view. Rather, it presented an opinion that is in complete contradiction to much of what geoscientists know about the physics of the earth and of the planetary impact processes.