EOR in Tight Oil Reservoirs through Wettability Alteration.pdf

SPE 166281
EOR in Tight Oil Reservoirs through Wettability Alteration
Prateek Kathel, SPE, and Kishore K. Mohanty, SPE, The University of Texas at Austin
Copyright 2013, Society of Petroleum Engineers

This paper was prepared for presentation at the SPE Annual Technical Conference and Exhibition held in New Orleans, Louisiana, USA, 30 September–2 October 2013.

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Abstract
In fractured reservoirs, the efficiency of water flood is governed by spontaneous imbibition of water into oil-containing
matrix blocks. When the matrix is oil-wet or mixed-wet, little oil can be recovered by imbibition. The objective of this work
is to identify chemicals that can be added to the injection water that can induce imbibition into an originally mixed-wet, tight,
fractured sandstone reservoir. Several surfactants were evaluated for their aqueous stability at the reservoir temperature and
salinity. Contact angles were measured on a clay-rich sandstone. Spontaneous imbibition tests were conducted on the
reservoir rocks. It is shown that the use of dilute ( wt %) surfactant solution can alter the wettability from oil-wet towards
more water-wet condition on the mineral plates. Incremental oil recovery a