ABSTRACT: Sequence Stratigraphy of the Upper and Middle "Canyon" Oil and Gas Fields Along the Eastern Edge of the Midland Basin, Irion County, Texas -- the Potential for Future Exploration
WHITSITT, PHILIP, Tucker Drilling Company, Inc., Midland, TX
Oil and gas fields near the eastern margin of the Midland basin in eastern Irion County, Texas, are productive from sandstone reservoirs informally referred to as "Canyon" sandstones. These sandstones occur between Wolfcampian and Strawn limestones within a 2000-ft-thick section of predominantly shale and sandstone. Within this section, zones of predominantly sandstone are separated by spiculitic or cherty, calcareous shale/mudstones. The calcareous shales are less resistive than shales associated with the sandstones and are correlated easily in this area. Based on these correlations, the "Canyon" is divided into upper, middle, and lower "Canyon" sandstones.
With the exception of wells along the Irion-Tom Green county line, most Canyon production is from the upper through the middle Canyon; most wells do not penetrate the lower Canyon. Upper Canyon oil and gas fields include Rock Penn, Christi, Irion West, and Lucky Mag. Middle Canyon production comes from Zan Zan and some wells in the Brooks field.
The vertical and aerial positions of these fields suggest a prograding shelf margin and at least two episodes of lowstand deposition. A third lowstand, represented by sandstone near the top of the upper Canyon in the Clark field, also may have occurred, but a third fairway of lowstand fans has not been recognized, which may indicate a less-significant relative sea level fall. Sandstone reservoirs in the area are typically from these lowstand systems; however, the productive sand of the upper Canyon Lucky Mag field is interpreted to be within a highstand system. The sand quality and production of the Lucky Mag reservoirs is relatively poor.
An upper Canyon fairway of lowstand reservoirs has been well defined and heavily explored. The discovery of Zan Zan in 1988 demonstrated that a middle Canyon fairway also may be present. Much potential exists for many more Zan Zan fields to be found.
AAPG Search and Discovery Article #91018©1992 AAPG Southwest Section Meeting, Midland, Texas, April 21-24, 1992 (2009)