Fractures of the Dammam Dome Carbonate Outcrops:
Their Characterization
, Evolution and Implications to Deep Reservoirs
The Tertiary carbonates
of the Dammam Dome outcrops present
a useful opportunity to study fractures within the oil-producing region of
Saudi Arabia. The study focuses on: 1) the
characterization
and propagation of
the outcrop fractures, 2) their potential as analogues for the deep fractured
carbonate reservoirs of Dammam Dome and their equivalents in surrounding
fields, and 3) the possible presence of near-surface faults that may slip in
response to deep-seated salt growth of the Dome. We integrate field mapping and
measurements with aerial photographs and fold curvature analysis. The fractures
are observed within all exposed carbonate units, but predominantly within the
Middle Rus unit due to the vast exposures of this unit. The fractures are
opening-mode, bed-perpendicular joints that form orthogonal sets. Field
analysis indicates that joints developed independently of the later
locally-restricted karst structures. Fractures developed due to doming and
their spacing is controlled by bed thickness and lithology. Faults were not
found within surface outcrops, but their presence in subsurface is not
precluded. The joint patterns and spacing reflect both the geometry of the
doming strata, and mechanical stratigraphy. Consequently, the joint pattern can
provide a first-order conceptual fracture model for the Dome carbonate
reservoirs and other similar reservoirs in the region. Some of the quantitative
attributes of joints (e.g. orientations, and spacing) can be integrated with
the subsurface data to guide near-future
reservoir
development of Dammam Dome
and impose probability constraints on the subsequent simulation modeling.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California