Diagenetic Characteristics of Selected Sandstones Above, Within, and Below the Megacompartment Complex, Anadarko Basin, Oklahoma
Abstract
Most deep sedimentary basins in the world include a layered arrangement of at least two hydraulic systems (Powley, 1987, p. 1). In some basins, mainly onshore in the United States, a third hydraulic system is present. In these three-layered hydraulic systems, the shallowest and deepest systems are basin-wide, and pressures are subnormal to normal. The middle hydraulic system generally is not basin-wide and in this system are compartments of abnormally high pressures. Mechanisms of abnormal pressuring were described by Dickinson (1953), Powers (1967), Baker (1972), and Bradley (1975). These mechanisms include structural differentiation, clay diagenesis, aquathermal pressuring, compaction, compartmentation by seal-development, and combinations of these various mechanisms. An example of a basin with three hydraulic systems is the Anadarko Basin; abnormally overpressured compartments are in the middle system. These compartments are a two-component subsystem that consists of porous and permeable rock surrounded by a seaL Geological processes that are important to the formation of these compartments are subsidence, sedimentation and diagenesis. The study of pore-pressure data and subsurface geological data from the Anadarko Basin indicates the presence of a basinwide, overpressured, completely sealed compartment. The term megacompartmenl complex (MCC), was introduced by Al-Shaieb (1991) to describe this hydraulic system. The megacompartment complex is bounded by top, basal and lateral seals. It is approximately 240 km (150 mi) long, 110 km (70 mi) wide and is at least as thick as 4800m (16,000 ft) (Al-Shaieb and others, 1993, p. 70). The top seal is 10,000 to 11,000 feet below the surface (AJ-Shaieb and others, 1992, p. 210), whereas the basal seal is the Devonian Woodford Shale.
Collections
- OSU Theses [15752]