A fresh approach to ditch cutting analysis as an aid to exploration in areas affected by large igneous province (LIP) volcanism
J. M. Millett, M. J. Hole, D. W. Jolley, 2014. "A fresh approach to ditch cutting analysis as an aid to exploration in areas affected by large igneous province (LIP) volcanism", Hydrocarbon Exploration to Exploitation West of Shetlands, S. J. C. Cannon, D. Ellis
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Where hydrocarbon exploration targets occur within basins affected by large igneous province (LIP) sequences, an understanding of the volcanic stratigraphy is essential in compiling accurate basin models at all scales. Ditch cutting samples are one of the most commonly available sources of data yielding information in the context of LIP stratigraphy such as phenocryst load, degree of secondary precipitation and lava composition, largely unattainable by remote sensing. Where core data is limited or absent, cuttings provide the only means of accessing such data along with valuable inference of volcanic facies development and down-hole conditions. Interpretations based on cuttings data are widely used in industry and, as such, a repeatable and well-defined methodology for the analysis and designation of volcanic facies from cuttings is an important requirement for regional and individual play modelling. Such an approach has not been common practice to date. We propose a system of basic percentage-based cuttings analysis and ternary classification specifically tailored to LIP sequences, and argue for the benefits of a coherent and transparent basin-wide approach. The classification system is further developed into a log-style output for easy integration and comparison with other down-hole geophysical and biostratigraphic data.
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This volume addresses the challenges facing explorers and developers alike in a region that is becoming a major focus of the petroleum industry in the United Kingdom, Faroes and North Norway. Several West of Shetland fields are still in the appraisal phase almost a decade after discovery. Sub-volcanic exploration risks remain high: sub-volcanic structural traps are imaged poorly, and so the geophysical community is responding with the application of latest technology. The more simple reservoirs might not be large enough to prompt informed and speedy development decisions; larger fields might have a combination of complexities, requiring a phased approach to the development. Infrastructure has been slow to arrive and planned developments have been subject to dramatic swings in fiscal regime ranging from special allowances to unexpected tax increases.
Environmental challenges are significant when moving into more remote, deeper water. The perception of these challenges by the third parties has become much more acute. To sustain its right to operate, the industry has to demonstrate safe drilling operations and appropriate response capability with government agencies.