METHOD AND APPARATUS FOR INJECTING ONE OR MORE FLUIDS INTO ABOREHOLE

摘要

A method and an apparatus for injecting a fluid into a borehole. The method includes the step of injecting an injection fluid into a primary injection zone in a borehole at an injection fluid pressure. The primary injection zone is bound ed by a proximal injection zone interface and a distal injection zone interface. The proximal injection zone interface and the distal injection zone interface are maintained at pressures which are substantially balanced with the injection fluid pressure . The apparatus includes a body adapted for passage through a borehole, at least four radially extendable and retractable zone interface elements spaced longitudinally alo ng the body which when extended define at least three zones along the body, a zone interface element actuator for selectively extending and retracting the zone interface elements, and a fluid delivery system for delivering a fluid to each zone. The central zone defined by the zone interface elements is the primary injection zone and the zones o n either side of the primary injection zone are balancing zones which are used to achieve substantial pressure balancing with the fluid injection pressure at the proximal injecti on zone interface and the distal injection zone interface.