Changes

===Well and seismic constraints===

===Well and seismic constraints===

Cross sections and maps are usually constructed simultaneously and need to be continually checked against each other (see [[Geological cross sections]] and [[Subsurface maps]]). The first well in a field provides depth, velocity, dipmeter, and hydrocarbon distribution information that can improve the accuracy of predrill seismic and geological interpretations. Time pick corrections and seismic reprocessing generate improved seismic sections. Ideally, seismic sections should be time migrated and displayed with no vertical exaggeration so that true scale cross sections can be constructed for section restoration and balancing.<ref name=Dahlstrom_1970>Dahlstrom, C. D. A., 1970, Structural geology in the eastern margin of the Canadian Rocky Mountains: Canadian Society of Petroleum Geologists Bulletin, v. 18, p. 332-406.</ref>

[[Cross section]]s and maps are usually constructed simultaneously and need to be continually checked against each other (see [[Geological cross sections]] and [[Subsurface maps]]). The first well in a field provides depth, velocity, dipmeter, and hydrocarbon distribution information that can improve the accuracy of predrill seismic and geological interpretations. Time pick corrections and seismic reprocessing generate improved seismic sections. Ideally, seismic sections should be time migrated and displayed with no vertical exaggeration so that true scale cross sections can be constructed for section restoration and balancing.<ref name=Dahlstrom_1970>Dahlstrom, C. D. A., 1970, Structural geology in the eastern margin of the Canadian Rocky Mountains: Canadian Society of Petroleum Geologists Bulletin, v. 18, p. 332-406.</ref>

Production wells may lie off the lines of seismic and geological section so that data will have to be projected carefully onto the lines using seismic cross lines or down-plunge projection.<ref name=DePaor_1988>DePaor, D., 1988, [http://archives.datapages.com/data/bulletns/1988-89/data/pg/0072/0001/0050/0073.htm Balanced section in thrust belts, Part 1--Construction]: AAPG Bulletin, v. 72, p. 73-90.</ref>

Production wells may lie off the lines of seismic and geological section so that data will have to be projected carefully onto the lines using seismic cross lines or down-plunge projection.<ref name=DePaor_1988>DePaor, D., 1988, [http://archives.datapages.com/data/bulletns/1988-89/data/pg/0072/0001/0050/0073.htm Balanced section in thrust belts, Part 1--Construction]: AAPG Bulletin, v. 72, p. 73-90.</ref>