Changes

The marine shelf is an environment affected by storm- and tidal-driven waves and currents and sometimes by oceanic currents. Although shelf sand ridges of either storm or tidal origin formed during transgression are the best known examples (Figure 3g), sand bodies associated with the marine shelf also include reworked delta front and barrier sands, amalgamated storm sheets, and oceanic current deposits.<ref name=pt06r10>Barwis, J. H., 1989, The explorationist and shelf sand models—where do we go from here?: 7th Annual Research Conference Proceedings, Gulf Coast SEPM, p. 1–14.</ref>

The marine shelf is an environment affected by storm- and tidal-driven waves and currents and sometimes by oceanic currents. Although shelf sand ridges of either storm or tidal origin formed during transgression are the best known examples (Figure 3g), sand bodies associated with the marine shelf also include reworked delta front and barrier sands, amalgamated storm sheets, and oceanic current deposits.<ref name=pt06r10>Barwis, J. H., 1989, The explorationist and shelf sand models—where do we go from here?: 7th Annual Research Conference Proceedings, Gulf Coast SEPM, p. 1–14.</ref>

Most marine sand bodies are upward coarsening with the best reservoir quality rocks at the top of the body. Gamma ray, SP, and resistivity logs have a corresponding upward-coarsening character. In the case of storm-deposited sheet sands either attached or detached from the shoreface, amalgamation of individual storm deposits at the top of the bodies produces the greatest permeability and porosity and the most laterally continuous units.<ref name=pt06r8>Atkinson, C. D., Goesten, B. G., Speksnijder, A., vander Vlugt, W., 1986, Storm-generated sandstone in the Miocene Miri Formation, Seria Field, Brunei (N., W. Borneo), in Knight, R. J., McLean, J. R., eds., Shelf Sands and Sandstones: Canadian Society of Petroleum Geologists Memoir 11, p. 213–240.</ref><ref name=pt06r38>Gaynor, G. C., Scheihing, M. H., 1988, Shelf depositional environments and reservoir characteristics of the Kuparuk River Formation (Lower Cretaceous), Kuparuk field, North Slope, Alaska, in Lomando, A. J., Harris, P. M., eds., Giant oil and gas fields—A core workshop: Society of Economic Paleontologists and Mineralogists Core Workshop 12, p. 333–389.</ref> In the case of tidal- and storm-generated shelf sand ridges, best reservoir quality is also at the top in the form of several different types of large scale cross bedding.

Most marine sand bodies are upward coarsening with the best reservoir quality rocks at the top of the body. [[Basic open hole tools#Gamma ray|Gamma ray]], [[Basic open hole tools#Spontaneous potential|SP]], and [[Basic open hole tools#Resistivity|resistivity]] logs have a corresponding upward-coarsening character. In the case of storm-deposited sheet sands either attached or detached from the shoreface, amalgamation of individual storm deposits at the top of the bodies produces the greatest [[permeability]] and [[porosity]] and the most laterally continuous units.<ref name=pt06r8>Atkinson, C. D., Goesten, B. G., Speksnijder, A., vander Vlugt, W., 1986, Storm-generated sandstone in the Miocene Miri Formation, Seria Field, Brunei (N., W. Borneo), in Knight, R. J., McLean, J. R., eds., Shelf Sands and Sandstones: Canadian Society of Petroleum Geologists Memoir 11, p. 213–240.</ref><ref name=pt06r38>Gaynor, G. C., Scheihing, M. H., 1988, Shelf depositional environments and reservoir characteristics of the Kuparuk River Formation (Lower Cretaceous), Kuparuk field, North Slope, Alaska, in Lomando, A. J., Harris, P. M., eds., Giant oil and gas fields—A core workshop: Society of Economic Paleontologists and Mineralogists Core Workshop 12, p. 333–389.</ref> In the case of tidal- and storm-generated shelf sand ridges, best reservoir quality is also at the top in the form of several different types of large scale cross bedding.

===Deep water marine deposits===

===Deep water marine deposits===