Drilling apparatus and technique using down-hole motor

Abstract

The disclosure includes additional features of the apparatus and technique disclosed in Applicant's U.S. Pat. No. 3,854,539 and U.S. Pat. No. 3,874,464. For example, in one embodiment, the anvil is relatively rotatably interconnected with the piston-like member, and is adapted to engage the drill rod for conjoint rotation therewith. Moreover, the inner drill bit has a port in it for discharging the exhaust fluid into the working face of the outer bit from a passage in the anvil. In another embodiment, the anvil includes a core barrel which is adapted to register with the opening in the abutment, when the anvil is engaged with the abutment. The core barrel is defined by a tube which is detachably connected with the main body of the anvil at the relatively forward end thereof. After the tube has been detached from the anvil, the core sample is discharged from the tube through an opening in the relatively rearward end thereof, there being a core catcher means in the tube which is operable to retain the core sample against escape through the relatively forward end thereof. Manipulatively, the additional features include a process for installing an elongated element, such as a tube, in an earth formation. In the process, a drill rod is driven into the formation, having inner and outer bits at the distal end thereof, the inner of which is retractable from the rod through the bore of the pipe. After the inner bit is retracted, the elongated element is inserted in the bore, and then the rod is retracted from the hole about the element. Additionally, the added features include a process for removing a core sample from beneath overburden, using the foregoing pair of bits. After the inner bit is retracted from the bore, a core barrel is inserted in the bore, and the hole is excavated still further while the core barrel is driven forward in unison with the drill rod and adjacent the opening of the outer bit. The barrel is then retracted from the bore to remove the sample from the formation.