Joseph M. Reilly

Amplitude and Bandwidth Recovery Beneath Gas Zones Using Kirchhoff Prestack Depth Q-Migration

Summary When imaging geologic structures below a viscoaoustic overburden, it is important to account for amplitude dimming, frequency loss, and phase distortion. Several viscoaoustic wave-equation based methods have been developed to solve this problem. We present a Kirchhoff approach. The technical significance of this approach is that we have found an efficient way to compute frequency-dependent traveltimes, which are crucial in the Kirchhoff integral. The validity of our technology is illustrated by data examples.

Mitigation of overburden effects in fracture prediction using azimuthal AVO analysis: An example from a Middle East carbonate field

The ability to identify fracture clusters and corridors and their prevalent direction within many carbonates and unconventional shale gas/tight gas reservoirs may have a significant impact on field development planning as well as on the placement of individual wells. We believe seismic fracture prediction provides the best opportunity to identify the spatial distribution of fracture corridors, but the reliability of seismic fracture detection technology is constantly being questioned. The criticism results from the degree to which the acquisition footprint, random and coherent noise in the seismic data, and near-surface/overburden issues affect extracted seismic “fracture” attributes. Therefore, a key issue is the separation of artifacts caused by the acquisition footprint and near-surface or overburden anisotropy/structural variations from the anomalies caused by the presence of fractures.

Seismic fracture prediction using azimuthal AVO analysis in a Middle East carbonate field: workflow and mitigation of overburden effects

Summary Seismic-fracture prediction is based on the fact that, in fractured rocks, seismic velocity varies with the direction of wave propagation relative to the fracture orientation (azimuthal anisotropy), which causes seismic amplitude to vary with azimuth (azimuthal AVO or AVOAZ). The theory of wave propagation in fractured rocks is well documented, but many issues remain to be resolved before this technology can be used routinely. These issues include overcoming problems related to acquisition and overburden effects and determining optimal data processing and signal enhancement methods. . In this paper, we apply a targetoriented AVOAZ processing workflow, which includes, but is not limited to, data conditioning, suppression of the acquisition footprint and mitigation of near-surface and overburden effects to extract fracture-anisotropy attributes in a carbonate oil field in UAE.

The case for separate sensor processing: Meeting the imaging challenge in a producing carbonate field in the Middle East

Carbonate platforms in the Middle East continue to represent an important source of hydrocarbon reserves. For more than 20 years, interpretation and attribute extraction from time-based 3D seismic imaging products have been base geoscience data in this production setting. With the continuing advances in seismic imaging, geophysicists have an obvious interest in applying the most current algorithms to their projects. However, many of these carbonate reservoirs have accompanying imaging challenges that cannot be addressed solely through the application of new imaging technology. Alternative processing strategies must be considered, either to replace more conventional approaches and/or to prepare the data so that they conform to the limitations of the imaging algorithm.

SEG Applied Research Workshop: Geophysical challenges in southeast Asia exploration

The 2008 SEG Applied Research Workshop, in Kuala Lumpur, Malaysia on 7–10 April 2008, was the first such event to focus on regional challenges rather than on a specific technical topic. This is a premier example of how SEG is exploring for new ways to reach out and encourage more interaction with its global membership base. The workshop attracted 64 attendees, with regional representation from Malaysia, Thailand, Indonesia, and India; attendees from outside the region represented North America, Europe, and Australia. The participants covered the full spectrum of business interests: international oil companies, national oil companies, independent oil companies, research institutes, and geophysical service providers. The workshop was sponsored by Hess Corporation, ExxonMobil, and National GeoConsultant of Indonesia.

Paradigm shift in 3D multicomponent seismic imaging in the Arabian Gulf

Ocean-bottom cable (OBC) technology has many applications in petroleum exploration and exploitation. It permits us to acquire data in areas with intensively developed production infrastructure that impede conventional marine-streamer acqui- sition. Permanently installed OBC systems provide data for monitoring production from reservoirs. In addition to their logistical advantages, OBC systems also allow us to acquire multicomponent data. Typically, 2-C OBC data are acquired by two types of detectors: hydrophones (fluid-pressure change detectors) and single- or multicomponent geophones (particle-velocity or acceleration detectors). The multicomponent character of OBC data permits us to discriminate between upcoming and downgoing waves and to attenuate water-column reverberations. At the same time, because of the differences between the physical measurement characteristics of hydrophones and geophones, their data character (including noise levels, multiple content, coupling effects) can be very different. Th...

3D prestack data mining to meet emerging challenges

As we enter the 21 century, geoscientists are expected to extract even more detailed information from seismic data. The effective utilization of 3D prestack imaged (migrated) data allows for a step change in the ability to extract stratigraphic and structural information from seismic data, improve qualitative and quantitative attribute analysis and compensate for, in the interpretation phase, limitations in the seismic processing process.

Introduction to this special section: OTC.10 and Offshore technology

From 3–6 May 2010, SEG will again cosponsor the Offshore Technology Conference, also known as OTC.10, the worlds foremost event for the development of offshore resources in the fields of drilling, exploration, production, and environmental protection. OTC, founded in 1969, is now held annually at Reliant Center in Houston.

Imaging Challenges in a Producing Mideast carbonate platform environment

Summary This paper summarizes some of the seismic imaging challenges associated with a producing field in the Arabian Gulf. Overburden effects and their impact on the seismic data quality are discussed. We describe an approach which partially compensates for these effects in the time domain, thereby increasing the utility of this seismic dataset.

The role of alternative scenarios and a regional geologic framework for subsalt and deep exploration

Over 50 years ago Wallace Pratt, a preeminent geologist with the Humble Oil and Refining Company, had it right when he said “Where oil is first found is in the minds of men…” Today, many minds—of both men and women—are finding exploration opportunities by developing new, innovative exploration concepts based on regional understanding combined with breakthrough imaging technologies.