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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 41 (1957)

Issue: 2. (February)

First Page: 361

Last Page: 361

Title: Factors Relating to Previous HitFaultNext Hit Seals in Some California Oil Fields: ABSTRACT

Author(s): Albert F. Woodward

Article Type: Meeting abstract


The Previous HitfaultNext Hit-seal problem is of particular importance in California because of the many significant regional and local Previous HitfaultNext Hit systems affecting more than half of the known oil pools.

Previous HitFaultNext Hit seals are not only barriers to the migration of oil and gas in Previous HitfaultNext Hit-trap fields, but are also important as secondary traps on anticlinal closures. The sealing effect of faults has complicated the field development, reservoir studies, pressure maintenance, and secondary-recovery programs, particularly in multi-block, multi-zone fields. Several factors which influence the effectiveness of Previous HitfaultNext Hit seals include (1) lithologic type of sedimentation, (2) type of faulting, (3) depth of burial during faulting, (4) magnitude of Previous HitfaultNext Hit displacement, (5) secondary cementation in Previous HitfaultNext Hit zone, (6) differential fluid pressure across faults, and (7) time of faulting versus accumulation.

The lithologic type of the sediments appears to be one of the most important factors responsible for the formation of Previous HitfaultNext Hit seals. The type of faulting and depth of burial during Previous HitfaultNext Hit slippage are also significant. Other factors such as cementation are locally important. Post-accumulation faulting has affected the separation and readjustment of some pools; others have been partly depleted by leakage. Pressure barriers resulting from Previous HitfaultNext Hit seals have caused abnormal reservoir pressures in some fields.

Major Previous HitfaultNext Hit systems in the state can be related to local field patterns. This analogy has aided in the exploration of new Previous HitfaultTop-block accumulations within a proved field area as well as exploration for new fields.

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Copyright 1997 American Association of Petroleum Geologists