A double-walled drill pipe includes an outer drill pipe, an inner drill pipe and a drill pipe sealing apparatus. The outer drill pipe includes an axial through hole and a wall surface through hole, and the wall surface through hole is disposed in a wall surface of the outer drill pipe to connect the outside of the double-walled drill pipe and the axial through hole. The inner drill pipe is rotatably disposed in the axial through hole, and includes a fluid guiding hole connected to the wall surface through hole. The drill pipe sealing apparatus is disposed between the outer drill pipe and the inner drill pipe. The drill pipe sealing apparatus is axially located between a driving end and a connecting port of the wall surface through hole connected to the axial through hole. A drilling machine including the double-walled drill pipe is also provided.

A horizontal directional drilling system includes a drill head that includes a drive coupling with a central bore that is a through bore. The drill head includes a drive shaft that has an enlarged portion at a downhole end that defines a centroid positioned within the central bore of the drive coupling. The drive shaft includes a drive shaft axis that is misaligned and intersects with an end casing axis of an end casing at a balance point of the drill head. The centroid of the drive shaft is positioned to be coincident with the balance point of the drill head.

A pipe assembly used in horizontal directional drilling operations. The pipe assembly has an outer member, an inner member, and first removable collar. The inner member has a polygonal outer profile of uniform shape along its length and is partially contained within the outer member. The first removable collar is supported on the inner member within the outer member and limits relative axial movement of the inner member and the outer member.

Drill bits are provided for a drilling while driving machine. In some cases, the drill bit is a multi-stage bit capable of selectively cutting at two different diameters. In others, the bit is an expanding bit that can be passed through a foundation component while its being driven. The bit has a pair of cutting wings that can move between a retracted orientation where the bit's diameter is narrower than the inner diameter of the driven component, to a splayed orientation where the diameter is equal to or larger than the driven component's outside diameter.

A machine for rotary driving screw anchors into underlying ground and related. The machine has a mast with a rotary driver and a mandrel driver oriented on a common axis. The mandrel driver passes a mandrel through the rotary driver and the screw anchor to allow the mandrel to be actuated ahead of the screw anchor while the rotary driver drives the screw anchor into the ground. Alternatively, the mandrel driver may also drive a hammering drill through the screw anchor to clear a path ahead of it through subsurface rocks.

One exemplary embodiment provides a dual-speed dual-core enhanced drilling equipment which comprises an outer cylinder, a downhole power device, a large cutting head and a small cutting head, wherein the large cutting head is provided with a first centerline, a through hole arranged along the first centerline and a first diameter; the outer cylinder is sleeved outside the downhole power device and forms an annular space, and the outer cylinder directly or indirectly connects the upper drill string with the large cutting head so that the large cutting head and the downhole power device can rotate together with the upper drill string; the downhole power device is provided with a power generation section capable of generating power and a rotation output section which penetrates through the through hole to be connected with the small cutting head and provides independent power for the small cutting head, so that the small cutting head revolves around the first centerline under the driving of the upper drill string while rotating under the driving of the downhole power device. The exemplary embodiment can avoid the problem that the linear velocity of the central point of the large cutting head is zero, and is beneficial to improving the drilling speed.

A dual member drill string having a plurality of dual member drill string sections for use in horizontal directional drilling operations. Each drill string section having an outer member and an inner member that is rotatable independently of the outer member. The outer member has a pin end and a box end. The inner member has a pin end disposed within the pin end of the outer member and a box end disposed within the box end of the outer member.

A machine for rotary driving screw anchors into underlying ground and related. The machine has a mast with a rotary driver and a mandrel driver oriented on a common axis. The mandrel driver passes a mandrel through the rotary driver and the screw anchor to allow the mandrel to be actuated ahead of the screw anchor while the rotary driver drives the screw anchor into the ground. Alternatively, the mandrel driver may also drive a hammering drill through the screw anchor to clear a path ahead of it through subsurface rocks.

A pipe assembly used in horizontal directional drilling operations. The pipe assembly has an outer member, an inner member, and first removable collar. The inner member has a polygonal outer profile of uniform shape along its length and is partially contained within the outer member. The first removable collar is supported on the inner member within the outer member and limits relative axial movement of the inner member and the outer member.

An apparatus and method for preventing drill string drag. Rotation encoders are provided for tracking the rotation of an inner and outer member of a dual-member drill string. Based upon the drilling conditions, the readings of the encoder can detect when the inner member is dragging on the outer member. When such a drag condition is detected, a processor can trigger remedial measures, which may include increasing a rotation rate of the inner member, sending a warning signal, stopping operation, or a combination of these.