Reservoir
Connectivity: Definitions, Strategies, and Applications
Snedden, John W.1, Peter J.
Vrolijk2, Larry T. Sumpter1, Mike L. Sweet1,
Kevin R. Barnes1, Elijah White1, M. Ellen Meurer3
(1) ExxonMobil Upstream Research Company, Houston, TX (2) ExxonMobil Upstream
Research Co, Houston, TX (3) ExxonMobil Upstream Research Co, Houston,
Reservoir connectivity and
compartmentalization is a critical area of research and business application.
Surveying the general terrain of reservoir connectivity reveals significant
differences among companies and academics in how it is defined, measured,
modeled, and acted upon. However, almost all agree that connectivity is a
function of the field structural framework, reservoir stratigraphy, and fluid
characteristics.
Our approach to reservoir connectivity is
to define two entities: "static" and "dynamic"
connectivity. Static connectivity describes the native state of a field, prior
to production start-up. Evaluation of static connectivity is the basis for
proper assessment of original hydrocarbons in place and prediction of fluid
contacts in unpenetrated compartments.
Dynamic connectivity describes movement
of fluids once production has begun. Initiation of production actually perturbs
the original fluid distributions as pressure and saturation changes proceed in
a non-systematic fashion across field compartments. Barriers and baffles play a
varying role over the field life, in some cases breaking down over time,
suggesting that these are not true compartment boundaries. Analysis of dynamic
connectivity is essential to estimating ultimate recovery from a field.
We have developed a technology called
"Reservoir connectivity analysis" (RCA) to investigate field
compartments and associated connections. A compartment is precisely defined as
a trap which has no internal boundaries (e.g., faults, channel margins) which
would allow fluids to reach equilibrium at more than one elevation (over
geologic time scales). Connections between compartments include fault
juxtaposition windows and erosional scours between channels. Examples of RCA
application and its impact on our fields are discussed. In these mature
producing fields, RCA has explained production anomalies, generated new drill
well opportunities, and boosted field reserves above original estimates
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California