Changes

==Types of cores==

==Types of cores==

Continuous coring, first attempted in Holland in 1908,<ref name=pt05r12>Andersen, G., 1975, Coring and Core Analysis Handbook: Tulsa, OK, PennWell Books, 200 p.</ref> is usually most desirable, although many types of specialized core can be obtained.<ref name=pt05r123>Park, A., 1985, Coring, Part 2—core barrel types and uses: World Oil, v. 200, p. 83–90.</ref> Data from continuous core are typically combined with wireline log and formation test data to evaluate productivity. Diagenetically altered sandstones<ref name=pt05r123 /> and thinly laminated reservoirs<ref name=pt05r29>Bradburn, F. R., Cheatham, C. A., 1988, Improved core recovery in laminated sand shale sequences: Journal of Petroleum Technology, v. 40, p. 1544–1546., 10., 2118/18570-PA</ref> require laboratory analysis of large diameter cores to evaluate [[porosity]], hydrocarbon saturation, and net pay. (For more on continuous coring, see [[Conventional coring]].)

Continuous coring, first attempted in Holland in 1908,<ref name=pt05r12>Andersen, G., 1975, Coring and Core Analysis Handbook: Tulsa, OK, PennWell Books, 200 p.</ref> is usually most desirable, although many types of specialized core can be obtained.<ref name=pt05r123>Park, A., 1985, Coring, Part 2—core barrel types and uses: World Oil, v. 200, p. 83–90.</ref> Data from continuous core are typically combined with wireline log and formation test data to evaluate productivity. Diagenetically altered sandstones<ref name=pt05r123 /> and thinly laminated reservoirs<ref name=pt05r29>Bradburn, F. R., and C. A. Cheatham, 1988, Improved core recovery in laminated sand shale sequences: Journal of Petroleum Technology, v. 40, p. 1544–1546., 10., 2118/18570-PA</ref> require laboratory analysis of large diameter cores to evaluate [[porosity]], hydrocarbon saturation, and net pay. (For more on continuous coring, see [[Conventional coring]].)

An alternative to continuous coring is the retrieval of discrete samples from the wellbore face known as sidewall cores. These samples can provide useful details of the lithology, petrology, porosity, [[permeability]], and hydrocarbon content of the formation.<ref name=pt05r155>Toney, J. B., Speiglets, S. L., 1985, Coring, Part 6—sidewall operations: World Oil, v. 201, p. 29–36.</ref> The analytical results can be used to verify log analysis calculations. Selection of sidewall core points after logging allows selective sampling of specific zones.<ref name=pt05r38>Craft, M., Keelan, D. K., 1985, Coring, Part 7—analytical aspects of [[sidewall coring]]: World Oil, v. 201, p. 77–90.</ref> (See also [[Sidewall coring]].)

An alternative to continuous coring is the retrieval of discrete samples from the wellbore face known as sidewall cores. These samples can provide useful details of the lithology, petrology, porosity, [[permeability]], and hydrocarbon content of the formation.<ref name=pt05r155>Toney, J. B., and S. L. Speiglets, 1985, Coring, Part 6—sidewall operations: World Oil, v. 201, p. 29–36.</ref> The analytical results can be used to verify log analysis calculations. Selection of sidewall core points after logging allows selective sampling of specific zones.<ref name=pt05r38>Craft, M., and D. K. Keelan, 1985, Coring, Part 7—analytical aspects of sidewall coring: World Oil, v. 201, p. 77–90.</ref> (See also [[Sidewall coring]].)

==Sampling techniques==

==Sampling techniques==