Crosswell Electromagnetic Tomography: From Resistivity Mapping to Interwell Fluid Distribution

EMSE: Synergizing EM and seismic data attributes for enhanced forecasts of reservoirs

“…(For interpretation of the references to color in this figure caption, the reader is referred to the web version of this paper.) for jointly using surface seismic and EM data may arise, in crosswell settings resolutions for EM imaging are around 35-60 m (Marsala et al, 2008;Schlumberger, 2009) and 10-25 m for seismic (Schlumberger, 2010(Schlumberger, , 2013. These resolutions are similar to those considered for the reservoir simulator (50 m) and hence resolution challenges are negligible.…”

“…Crosswell electromagnetic tomography were introduced in the early 1990s to overcome the lack of sensitivity and improve interwell mapping (Wilt and Alumbaugh, 2003). DePavia et al (2008) presented an overview of the progress that has been made in imaging via EM technology and Marsala et al (2008) showed the ability of crosswell induction tomography to achieve accurate resolution for interwells even spaced more than 1 km apart. Similarly, controlled source electromagnetics were proven to be useful to overcome some of the challenges faced by seismic exploration, while improving existing mapping of the subsurface reservoirs in addition to supporting seismic operations, such as sub-salt and sub-basalt, where seismic explorations are costly and inefficient (Strack, 2013).…”

Applications of tomography in the oil-gas industry – Part 2

“…Although conventional resistivity logs indicated the near-wellbore section was essentially watered out, a deep-reading EM survey revealed areas of variable sweep efficiency between the wells (Al-Ali et al, 2009). The final results of this pilot field study have been described by Marsala et al (2008). …”

“…To better monitor movements of hydrocarbon fluid lying between wells at a reservoir scale, fluid-saturation surveys based on cross-well EM induction tomography have been performed Wilt et al, 1995;DePavia et al, 2008;Wilt, Donadille, AlRuwaili, Ma, & Marsala, 2008;Marsala et al, 2008. Surface-to-borehole EM uses an array of borehole receivers and a movable surface source, Pardo, Torres-Verdín, Marsala et al, 2011).…”

Evaluation of Borehole Casing Sources for Electromagnetic Imaging of Deep Formations

“…The specificity of borehole to surface EM (BSEM), in respect to crosswell EM (Xwell EM), is that BSEM requires only one surveyed well to obtain an areal map of fluid distribution of a reservoir target layer, kilometers away from the transmitting well (up to 4 km, as demonstrated in Saudi Arabian pilots, Marsala et al 2011 and2013a). Xwell EM, on the contrary, allows higher resolution results, but it is limited to cross sections between two or more wells, close enough for EM propagation: about 1 km in open holes, less in cased holes (Marsala et al 2008).…”