Homing in on sweet spots in Cretaceous Austin chalk

Journal Article · Mon Nov 29 00:00:00 EST 1993 · Oil and Gas Journal; (United States)

OSTI ID:5865586

Thomas, G E ^[1]; Sonnenberg, F P

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1. Thomas and Associates, Denver, CO (United States)

In discussing the nature and causes of fracturing in the Cretaceous Austin chalk of south central Texas, many geologists and operators involved in horizontal drilling of the chalk consider regional rock stress as the probable main cause of the fractures. If Austin chalk fractures are mainly the result of regional extensional stress without localizing factors, then fractured sweet spots are randomly distributed and successful exploration is more or less a matter of luck, usually dependent upon the coincidental placement of a seismic line. But if local, deep-seated structure or basement topography are the main causes of sweet spots, then a successful exploration method would be to first delineate the basement paleo structure or topography and secondly, place a seismic line to confirm the delineated features. Finding localities of maximum fracturing and production would than be based on scientific logic rather than luck. It is the purpose of this article to present the results of an examination of these alternative causes for the Austin chalk fracturing in the hope of determining the most cost effective exploration method for the fractured chalk reservoir.

• OSTI ID: 5865586
• Journal Information: Oil and Gas Journal; (United States), Vol. 91:48; ISSN 0030-1388
• Country of Publication: United States
• Language: English

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