Page 176 - Enhanced Oil Recovery in Shale and Tight Reservoirs

160 Enhanced Oil Recovery in Shale and Tight Reservoirs

Figure 7.5 Oil recovery from water huff-n-puff at different injection pressures.

initially in the core. Shen and Chen (2014) simulation results show that the
incremental oil recovery from water huff-n-puff over the primary deple-
tion is less than 2% higher. Therefore, the EOR potential for water
huff-n-puff is limited. Some of huff-n-puff water injection projects are
briefed below.

7.3.1 Huff-n-puff water injection in Bakken formation in
North Dakota
One water huff-n-puff pilot test was conducted in the North Dakota part of
the Bakken formation in 2012. The injection time was just over 1 month,
the soaking time was 2 weeks, and the production time was 3e4 months.
The injection rate was 1200 bbl/d. No water injectivity problem was
observed, but little to no oil rate was increased (Hoffman and Evans,
2016). Probably, 1 month of injection might not be long enough to inject
a minimum gas volume.

7.3.2 Huff-n-puff water injection in Parshall Field
EOG conducted a produced water injection test in a well in the Parshall
Field, the NDIC 17170. Injection began in the spring of 2012 with a plan
to operate the well in a huff-n-puff scheme according to a 30-day injection
and 10-day soak schedule. 10,000 barrels of water were injected in April and
29,000 barrels were injected in May 2012. There was no observable