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

Table 3

Percentage change of P-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	−3.6	0.94	2.4	—	3.2
High permeability no. 1	5.4	−6.1	2.5	—	−0.24	1.4
High permeability no. 2	8.0	−5.1	2.4	1.8	4.6	5.9
Lower permeability no. 1	4.0	−3.3	2.8	1.9	3.0	4.6
Lower permeability no. 2	5.4	−4.1	2.9	2.0	—	3.4