Print this pageAbstract: Scaling of Co-Current and Counter-Current Capillary Imbibition for Surfactant and Polymer Injection in Naturally Fractured Reservoirs
BABADAGLI, TAYFUN, Sultan Qaboos U.
To increase the capillary imbibition recovery rate and to deplete the matrix oil
efficiently, surfactant and polymer solutions can be injected into naturally fractured
reservoirs (NFR). Laboratory experiments are needed to understand the response of the
reservoir rock and fluids to these applications and a scale-up process is required to
quantify the recovery for reservoir conditions before injecting these expensive
fluids.This study tests the existing capillary imbibition scaling-up formulations in
literature and proposes modifications to them for surfactant and polymer injection
applications. Laboratory tests were performed using 500 mD Berea Sandstone cores of
different shapes and sizes with different boundary conditions. The rock samples was
surface-coated to create many different boundary conditions causing co or counter-current
imbibition or both. Kerosene, engine oil, mineral oil and crude oil were selected as the
oleic phase. Brine and two different concentrations of surfactant and polymer solutions
were used as the aqueous phase. The capillary imbibition recovery curves were then used to
test the existing scaling formulations. Modifications were introduced considering the
matrix boundary conditions, oil viscosity and wettability and were done either on the
Mattax and KyteAs scaling group or by combining this group with other scaling group for
the recovery by gravity segregation. In case of counter current flow, gravity force
becomes also effective for low IFT case and modification for surfactant injection is
required. For different matrix boundary conditions, aqueous solution properties, oil
viscosities and IFTs, applicable scaling formulations were defined for performance
estimation
of surfactant and polymer solution injection into NFR. Considering the
situations that the wettability, oil viscosity and IFT at reservoir conditions may not be
created at laboratory conditions, the scaling equations were modified to provide an
up-scaling of not only the matrix size but also these properties.
AAPG Search and Discovery Article #90911©2000 AAPG Pacific Section and Western Region Society of Petroleum Engineers, Long Beach, California