Discipline: Reservoir Description and
Dynamics
Shale
Sweet Spot Detection with Surface Seismic
Abstract:
One
of the greatest revolutions in the history of the oil and gas industry has
taken place over the past decade. This revolution is the rise of the shale
reservoirs. First drilled in the 1820s these reservoirs did not attract serious
attention due to their economics until the late 1990s when the Barnett Shale
emerged as an industry “game changer”.
Numerous
other shales rapidly attracted the attention of the industry until today dozens
of shales are currently being drilled throughout . This
revolution is rapidly spreading to many locations throughout the world.
Initially these shales were developed using statistical drilling methods in
which a large number of horizontal boreholes are drilled throughout the play.
Until
recently gas prices supported the economics of this approach. But due to their
success, an abundance of gas has caused a decrease in gas price and a new
economic paradigm has emerged, shale sweet spot drilling.
Production
from numerous shale plays indicates the existence of these sweet spots. These
result from certain geologic conditions, such as increased matrix porosity or
TOC, increased micro-fractures and areas with increased brittleness. These
reservoir characteristics affect the physical rock properties which, in turn,
affect a passing seismic signal.
Recent
advances in seismic interpretation have demonstrated that these shale reservoir
sweet spots can be detected prior to drilling. The ability to locate these
sweet spots before drilling significantly impacts the economics associated with
these plays. During this presentation a number of these seismic interpretation
methodologies will be discussed.