The review summarises the experience of geoscientists in predicting the existence, location, lithology, porosity and fluid content of oil and gas reservoirs; the emphasis being on geophysical analysis. Our intention is to provide all geoscientists in exploration and production with a reference document on lithology and fluid prediction and hence ensure a common awareness of current capabilities. Both good and bad experiences are included in the summary, so that we can learn from the lessons of the past. The examples are drawn from a range of companies and institutions.
Most of the experience is focused on the interpretation of seismic data, since seismic data are the prime source of information ahead of drilling. We review the use and accuracy of the various analysis techniques used in the interpretation. The accuracy of the results obtained from the different techniques depends on both the geological setting and stage of exploration or field development. The appropriate use of each analysis technique is illustrated in this review.
The form of the whole review is introduced in this section. A
short guide to its use is followed by a brief introduction of
the main ideas and concepts used in the other booklets. The analysis
techniques are summarised but a more extensive overview of them
(suitable for all geoscientists) can be found in the companion
report, the Tools Overview.
Locating a sand lens in a shale dominated system, detecting the oil water contact and estimating the lateral variation of porosity are all problems of predicting the Lithology and Fluid content of a reservoir. The range of problems is very broad. However, five common questions keep recurring in our discussions with Exploration & Production geoscientists.
We've compiled experience and insights on ways of solving these five common problems in separate sections. Each section can be read independently; we've kept them short to help rapid reference. Each has a selection of case histories to demonstrate the different type of analysis being used on real datasets. A list of key references has also been included. Key references are hyperlinked.
The simplicity of this approach for cataloguing the case histories is appealing, but geoscience isn't that easy. Problems overlap different categories, one person's definition is not the same as another's. So if you don't find what you are looking for in the first section you select, please scan the others.
Predicting permeability and the diagenetic properties of the reservoir are two additional issues of high priority. These particular issues are currently beyond our capabilities and, therefore, have not been included in this review. Further research is in progress to predict these reservoir characteristics.
This section introduces the ideas which are integral to this review. The reasons for the different types of analysis and the geological considerations are introduced. The analysis techniques are described in a companion volume to this review, The Tools Overview. Please refer to The Tools Overview for descriptions of the analysis techniques.
A glossary of technical jargon is provided. Terms in the glossary will be hyperlinked.
We intend to update the case histories in each of the booklets, periodically. You may consider contributing your ideas and case history material so that we can help distribute your experience to the industry.
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