2D Model Study of CO₂ Plumes in Saline Reservoirs by Borehole Resistivity Tomography

Table 2

Data set size of 4-pole configurations for a collinear N (32) electrode array and circulating crosshole array of 16 electrodes in each borehole.

Data set	Relation	Collinear (𝑁=32)	Circulating crosshole array (𝑁 = 16↔16)
Comprehensive, whole (independent, nonreciprocals)	𝑁(𝑁−1)(𝑁−2)(𝑁−3)/8; (α + β + γ) data	107,880	122,760
Comprehensive, effective (whole compreh.—redundant)	(α + β) data; (no γ + no noisy)	68,621	80,738
Dipole-dipole β (𝔞=1, 𝑛 = 1–6)	((𝑁−3)+(𝑁−8))×3	159	165
Wenner, α (CPPC)	(𝑁−1)(𝑁−2)/6	155	165

Redundant data include configurations of γ and noisy data of very low voltage.
Noisy data are those with geometric factor larger than that of dipole-dipole configuration of maximum dipole factor of 6.