Dual-injection frac systems in horizontal wells

Dual-injection frac systems are available for both openhole and cased-hole completions. The common practice is to pump the slurry through one conduit (tubing or annulus), while maintaining a low injection rate through the other (usually referred to as the "dead" string). However, both strings are always available for pumping and are often used to address special situations. The benefits of dual-injection frac systems are examined.