Hydrajet bottomhole completion tool and process

#The present invention relates generally to subterranean treatment operations, and more particularly to methods of isolating local areas of interest for subterranean treatment operations.

#In some wells, it may be desirable to individually and selectively create multiple fractures along a well bore at a distance apart from each other. The multiple fractures should have adequate conductivity, so that the greatest possible quantity of hydrocarbons in an oil and gas reservoir can be drained/produced into the well bore. When stimulating a reservoir from a well bore, especially those well bores that are highly deviated or horizontal, it may be difficult to control the creation of multi-zone fractures along the well bore without cementing a liner to the well bore and mechanically isolating the subterranean formation being fractured from previously-fractured formations, or formations that have not yet been fractured.

#One conventional method for fracturing a subterranean formation penetrated by a well bore has involved cementing a solid liner in the lateral section of the well bore, performing a conventional explosive perforating step, and then performing fracturing stages along the well bore. Another conventional method has involved cementing a liner and significantly limiting the number of perforations, often using tightly-grouped sets of perforations, with the number of total perforations intended to create a flow restriction giving a back-pressure of about 100 psi or more; in some instances, the back-pressure may approach about 1000 psi flow resistance. This technology generally is referred to as “limited-entry” perforating technology.

#FIG. 1 is a schematic cross-sectional view of an illustrative well completion assembly illustrating the perforation of a subterranean formation.

#FIGS. 2A and 2B are schematic cross-sectional views showing an illustrative window casing assembly according to the present invention. FIG. 2A depicts the illustrative window casing in a closed position. FIG. 2B depicts the illustrative window casing in an open position.

#FIGS. 3A-3D are schematic cross-sectional views illustrating various placements of fluid jet forming nozzles in the embodiment illustrated in FIGS. 2A and 2B.

#Referring now to FIG. 1, an illustrative completion assembly 100 includes a well bore 102 coupled to the surface 104 and extending down through a subterranean formation 106. Well bore 102 may drilled into subterranean formation 106 using conventional (or future) drilling techniques and may extend substantially vertically away from surface 104 or may deviate at any angle from the surface 104. In some instances, all or portions of well bore 102 may be vertical, deviated, horizontal, and/or curved.

#Conduit 108 may extend through at least a portion of well bore 102. In some embodiments, conduit 108 may be part of a casing string coupled to the surface 104. In some embodiments conduit 108 may be a liner that is coupled to a previous casing string. Conduit 108 may or may not be cemented to subterranean formation 106. When uncemented, conduit 108 may contain one or more permeable liners, or it may be a solid liner. As used herein, the term “permeable liner” includes, but is not limited to, screens, slots and preperforations. Those of ordinary skill in the art, with the benefit of this disclosure, will recognize whether conduit 108 should be cemented or uncemented and whether conduit 108 should be contain one or more permeable liners.

#Conduit 108 includes one or more fluid jet forming nozzles 110. As used herein, the term “fluid jet forming nozzle” refers to any fixture that may be coupled to an aperture so as to allow the communication of a fluid therethrough such that the fluid velocity exiting the jet is higher than the fluid velocity at the entrance of the jet. In some embodiments, fluid jet forming nozzles 110 may be longitudinally spaced along conduit 108 such that when conduit 108 is inserted into well bore 102, fluid jet forming nozzles 110 will be adjacent to a local area of interest, e.g., zones 112 in subterranean formation 106. As used herein, the term “zone” simply refers to a portion of the formation and does not imply a particular geological strata or composition. As will be recognized by those of ordinary skill in the art, with the benefit of this disclosure, conduit 108 may have any number of fluid jet forming nozzles, configured in a variety of combinations along and around conduit 108.