Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Exploring for structural traps

  | chapter = Exploring for structural traps

  | frompg  = 20-1

  | frompg  = 20-47

  | topg    = 20-70

  | topg    = 20-47

  | author  = R.A. Nelson, T.L. Patton, S. Serra

  | author  = R.A. Nelson, T.L. Patton, S. Serra

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch20/ch20.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch20/ch20.htm

==Crestal locations==

==Crestal locations==

Because the most important goal of exploration is economic success, locations are often chosen to provide maximum information on the economic viability of the prospect. Therefore, locations that assess the structurally highest point (crest) at the primary reservoir appear, at first, to be most attractive. However, other criteria in structural plays need to be recognized when determining prospect-assessing locations. This approach becomes critical as the structural complexity increases or the structural play concept becomes more sophisticated.

Because the most important goal of exploration is economic success, locations are often chosen to provide maximum information on the economic viability of the prospect. Therefore, locations that assess the structurally highest point (crest) at the primary [[reservoir]] appear, at first, to be most attractive. However, other criteria in structural plays need to be recognized when determining prospect-assessment locations. This approach becomes critical as the structural complexity increases or the structural play concept becomes more sophisticated.

==Off-crestal locations==

==Off-crestal locations==

Circumstances may occur in which it is more appropriate to select a location based on technical needs or data quality rather than optimizing the economic success of the first well. Generally, these locations provide greater certainty in evaluating data (e.g., clearly defined seismic reflectors to help define a crestal position). Other structural play concepts may require off-crestal positions to be viable.

Circumstances may occur in which it is more appropriate to select a location based on technical needs or data quality rather than optimizing the economic success of the first well. Generally, these locations provide greater certainty in evaluating data (e.g., clearly defined [[Seismic data|seismic reflectors]] to help define a crestal position). Other structural play concepts may require off-crestal positions to be viable.

Examples of circumstances in which it is desirable to drill a location other than the crest include the following:

Examples of circumstances in which it is desirable to drill a location other than the crest include the following:

* Certain fracture plays in the Rocky Mountain thrust belts of the U.S. and Canada may be sensitive to fore limb or back limb locations to provide the flow rates necessary to establish economic success.

* Certain [[fracture]] plays in the [[Rocky Mountains|Rocky Mountain]] [[thrust]] belts of the U.S. and Canada may be sensitive to forelimb or backlimb locations to provide the flow rates necessary to establish economic success.

* Tests in the offshore Netherlands have been drilled off crest and away from hinges to obtain an early assessment of matrix [[porosity]] in the reservoir.

* Tests in the offshore Netherlands have been drilled off crest and away from hinges to obtain an early assessment of matrix [[porosity]] in the reservoir.

* The position of the oil–water contact may be critical in defining the volume of hydrocarbons necessary for economic success.

* The position of the [http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term%20name&filter=oil-water%20contact oil–water contact] may be critical in defining the volume of [[hydrocarbon]]s necessary for economic success.

* A nonoptimal acreage position may preclude access to the crestal location.

* A nonoptimal acreage position may preclude access to the crestal location.

* Logistics problems (e.g., topography, environmental sensitivities) may preclude access to the crestal location.

* Logistics problems (e.g., topography, environmental sensitivities) may preclude access to the crestal location.

==See also==

==See also==

* [[Workflow to find a prospect]]

* [[Structural exploration workflow]]

* [[Tectonic setting]]

* [[Tectonic setting]]

* [[Structural domains]]

* [[Structural domains]]

* [[Structural fairway prospectivity]]

* [[Structural fairway prospectivity]]

* [[Lead and prospect delineation]]

* [[Structural lead and prospect delineation]]

* [[Structural exploration: thrust belt example]]

* [[Structural exploration: thrust belt example]]

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Exploring for structural traps]]

[[Category:Exploring for structural traps]]