Patent ID: 7690444
Filing Date: 2010-04-06
Classification: E21B

Abstract:
1. A method for drilling a lateral channel in a subterranean coal seam adjacent to an existing oil or gas well having a well casing, comprising: suspending a casing mill at a selected depth in the well casing and milling a section of the well casing, thus resulting in an annular perforation in the well casing adjacent to the subterranean coal seam; suspending an underreamer to the circular perforation and reaming-out the annular perforation a distance into the subterranean coal seam; suspending a guide shoe in the well to the annular perforation, wherein the guide shoe defines a window configured to open upon reaching the annular perforation; directing a flexible hose down the well casing and into the guide shoe, wherein the flexible hose terminates at a waterjet having a nozzle in fluid communication with a plurality of forward jets, a plurality of retro jets, and a plurality of radial jets; directing the waterjet through the window and out of the guide shoe in a substantially horizontal direction and into engagement with the subterranean coal seam; pumping a fluid at a high pressure through the flexible hose and waterjet, whereby the fluid is expelled from the waterjet via the plurality of forward, retro, and radial jets such that jets of high pressure fluid shoots at the subterranean coal formation to make a lateral channel therein; and translating the flexible hose back and forth manually within the lateral channel to advance the waterjet and flush out drilling particulates.