An Experimental and Modeling Study on the Response to Varying Pore Pressure and Reservoir Fluids in the Morrow A Sandstone

Table 4

Percentage change of S-wave velocity with increasing differential pressure from 15.17 MPa to 37.92 MPa.

Sample	Dry Rock Loading	Dry Rock Unloading	Brine Sat.	Oil Flushed	Oil-CO2 Flushed	CO2 Flushed
	(%)	(%)	(%)	(%)	(%)	(%)
Cemented	6.5	−4.3	2.3	2.3	—	2.9
High permeability no. 1	10.2	−8.3	7.7	—	10.5	7.7
High permeability no. 2	8.3	−6.4	8.7	9.7	10.3	9.1
Lower permeability no. 1	6.4	−5.2	5.0	5.9	5.3	5.7
Lower permeability no. 2	6.9	−5.5	3.4	3.9	—	4.4