(10d) Multiphase Flow in Unconventional Liquid Rich Shale Oil Reservoir

Multiphase
Flow in Unconventional Liquid Rich Shale Oil Reservoir

Richard Cao

Objectives/Scope:

The
objective of this paper is to study the complex multiphase flow recovery
process in unconventional Liquid Rich Shale oil reservoir with extremely
low permeability, especially the unusual high Water Oil

Ratio observed in the unconventional horizontal wells at Permian Basin, where
one barrel of oil production usually comes with 2 to 4 barrels of water
for the Avalon, Bone Spring, and Wolfcamp formations.

Methods,
Procedures, Process:

Numerical
modeling, field pilot test, and production trend analysis are integrated
to understand the oil, water, and gas recovery process in the
unconventional Liquid Rich Shale oil reservoir at Permian.

The numerical model was divided into three zones, matrix, hydraulic fracture,
and SRV (Stimulated Rock Volume). Different rock, fluid, and relative
permeability properties are implemented in these zones. A vertical pilot well
was drilled with isolated production from different stratigraphic layers
with different rock fluid properties to test the relationship of water cut
with subsurface parameters. The fractional flow from the pilot is compared with
the numerical results.

Results,
Observations, Conclusions:

Statically
History Match is performed to obtain good history matching of oil, gas,
and water from the actual production. The unusual behavior of high water oil
ratio in the Permian LRS horizontal wells is explained with fractional
flow from the matrix and fracture, as shown in attached Figure 1. It is found
that the water in the Liquid Rich Shale can flow despite the extremely low
nanoDarcy

permeability. The water from the matrix forms the base of the produced
water, enhanced by other subsurface geological features such as wet sand
layers, high perm non-net

pay zones, and natural fractures. At the same time, the hydraulic fracturing
process plays a very important role in determine the oil/water/gas
recovery process in the unconventional horizontal wells. The
production trend analysis and simulation results also indicate that the
water oil ratio is closely related to the gas oil ratio, as shown in the
attached Figure 2. For geologically similar area, higher gas oil ratio usually
indicates higher water oil ratio.

 Novel/Additive
Information:

There
are very limited studies about multiphase flow in unconventional Liquid Rich
Shale with extremely low permeability. There is no systematical study
(i.e., numerical and field test to verify with actual production) about
the oil/gas/water multiphase flow at Permian reported.