Climate stratigraphy [e-Book]

One of the most important steps in oil and gas E&P is the construction of a near-synchronous high-resolution stratigraphic framework. This stratigraphic framework forms the basis in the search for additional potential reservoirs and especially in reservoir characterization. Many reservoir intervals are barren of fossils, and conventional stratigraphic methods often lack the required level of resolution. An alternative stratigraphic approach is to use the climate record stored in the sedimentary rock record and subsequently recorded by facies-sensitive wireline logs. The science behind this approach is climate stratigraphy, which is a relatively new discipline combining advanced numerical processing of conventional log data with the theory of climate-driven cyclicity in sedimentary depositional systems. Extraction of the climatic signal from facies-sensitive wireline logs allows the construction of a high-resolution stratigraphic framework for both reservoir and regional scale correlation, more or less independently of other stratigraphic data. It is therefore a highly cost-effective and universally applicable method deserving of wider appreciation and use. These course notes include a discussion on the theory of climate changes and its effect to sedimentary facies and its relation to the stratal pattern architecture in the subsurface. This is followed by an extensive explanation of spectral analysis of facies-sensitive wireline logs and the transformation of logs. These log transforms or spectral attribute curves are used in well correlations for the construction of a near-synchronous stratigraphic correlation framework. The book is highly illustrated and it includes several examples from clastic as well as carbonate reservoir correlations.