Changes

==Clastic depositional lithofacies and environments==

==Clastic depositional lithofacies and environments==

Clastic depositional environments range from alpine to abyssal settings (Figure 3 and Table 2). Detailed reviews of these are given by Galloway and Hobday,<ref name=pt06r36>Galloway, W. E., Hobday, D. K., 1983, Terrigenous Clastic Depositional Systems Applications to Petroleum, Coal, and Uranium Exploration: New York, Springer Verlag, 423 p.</ref> Walker,<ref name=pt06r147 /> Berg,<ref name=pt06r14>Berg, R. R., 1986, Reservoir Sandstones: Englewood Cliffs, N., J., Prentice-Hall, 481 p.</ref> Reading,<ref name=pt06r107>Reading, H. G., ed., 1986, Sedimentary Environments and Facies, 2nd ed.: Boston, MA, Blackwell Scientific Publications, 615 p.</ref> Beaumont and Foster,<ref name=pt06r11>Beaumont, E. A., Foster, N. H., 1987, Reservoirs II—Sandstones: AAPG Treatise of Petroleum Geology Reprint Series No. 4, 573 p.</ref> and others. The following review is a cursory summary of the origin, lithofacies, geometry, and reservoir properties of major clastic environments and deposits. The reader should be aware that the remarks offered here for each depositional environment are necessarily of a highly generalized and idealized nature. Siliciclastic reservoirs are typically composed of multiple bodies deposited (and eroded) through time under varying tectonic, sealevel, and climatic conditions. Corresponding geometry, vertical sequence, wireline log character, and [[reservoir quality]] trends for a given reservoir may be, and often are, different from the generalized “single environment” models. In addition, subsequent diagenesis (see “[[Evaluating diagenetically complex reservoirs]]”) may alter the permeability and porosity structure created by depositional (and erosional) processes. However, it has been often observed that in siliciclastic rocks, diagenesis generally follows depositional fabric (see [[Geological heterogeneities]]). Complex structural patterns can reduce reservoir continuity as well.

Clastic depositional environments range from alpine to abyssal settings (Figure 3 and Table 2). Detailed reviews of these are given by Galloway and Hobday,<ref name=pt06r36>Galloway, W. E., Hobday, D. K., 1983, Terrigenous Clastic Depositional Systems Applications to Petroleum, Coal, and Uranium Exploration: New York, Springer Verlag, 423 p.</ref> Walker,<ref name=pt06r147 /> Berg,<ref name=pt06r14>Berg, R. R., 1986, Reservoir Sandstones: Englewood Cliffs, N., J., Prentice-Hall, 481 p.</ref> Reading,<ref name=pt06r107>Reading, H. G., ed., 1986, Sedimentary Environments and Facies, 2nd ed.: Boston, MA, Blackwell Scientific Publications, 615 p.</ref> Beaumont and Foster,<ref name=pt06r11>Beaumont, E. A., Foster, N. H., 1987, Reservoirs II—Sandstones: AAPG Treatise of Petroleum Geology Reprint Series No. 4, 573 p.</ref> and others. The following review is a cursory summary of the origin, lithofacies, geometry, and reservoir properties of major clastic environments and deposits. The reader should be aware that the remarks offered here for each depositional environment are necessarily of a highly generalized and idealized nature. Siliciclastic reservoirs are typically composed of multiple bodies deposited (and eroded) through time under varying tectonic, sealevel, and climatic conditions. Corresponding geometry, vertical sequence, wireline log character, and [[reservoir quality]] trends for a given reservoir may be, and often are, different from the generalized “single environment” models. In addition, subsequent diagenesis (see [[Evaluating diagenetically complex reservoirs]]) may alter the permeability and porosity structure created by depositional (and erosional) processes. However, it has been often observed that in siliciclastic rocks, diagenesis generally follows depositional fabric (see [[Geological heterogeneities]]). Complex structural patterns can reduce reservoir continuity as well.

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