Abstract: A motor-powered directional drill is advanced in an inverted arcuate path underneath an obstacle such as a water course. A second concentric and larger lining pipe follows the advance of the directional drill either simultaneously but preferably sequentially to form a concentric annulus about the directional drill. This lining pipe preserves the directional drilling path made and prevents the collapse or the erosion of the hole due to manipulation of the directional drill. When the inverted path underneath the obstacle is completed and the liner extends the full length, the liner becomes a large diameter pipe of improved tortional capability which can be used subsequently to ream the hole to full size for placement of a production casing. A specialized drilling rig is provided having one advancing chuck for crowding the directional drill into the ground and another larger rotating chuck to rotate and advance the following lining pipe into the ground concentrically about the directional drill.

Abstract: A system and method for emplacing a relatively large casing under and spanning an obstacle such as a river is disclosed. The casing is emplaced along the path of a previously bored and placed existing pilot string running beneath the obstacle. The pilot string extends typically in an inverted arcuate contour from a first position at or near ground level on one side of the obstacle to a second position at or near ground level on the other side of the obstacle. The system includes apparatus for concentrically reaming the pilot hole to an enlarged diameter and entraining the cuttings from the excavated annulus of the reaming operation in drilling mud. The casing is advanced along the reamed pilot hole in following relationship to the reaming apparatus. A seal is provided between the outer surface of the leading portion of the casing and the reamed pilot hole so that the drilling mud containing the entrained cuttings flows into the leading end of the advancing casing.

Abstract: A motor-powered directional drill is advanced in an inverted arcuate path underneath an obstacle such as a water course. A second concentric and larger lining pipe follows the advance of the directional drill either simultaneously but preferably sequentially to form a concentric annulus about the directional drill. This lining pipe preserves the directional drilling path made and prevents the collapse or the erosion of the hole due to manipulation of the directional drill. When the inverted path underneath the obstacle is completed and the liner extends the full length, the liner becomes a large diameter pipe of improved tortional capability which can be used subsequently to ream the hole to full size for placement of a production casing. A specialized drilling rig is provided having one advancing chuck for crowding the directional drill into the ground and another larger rotating chuck to rotate and advance the following lining pipe into the ground concentrically about the directional drill.

Abstract: A system and method of installing a production casing along an inverted underground arcuate path beneath and spanning an obstacle such as a river is disclosed. The casing is installed along the inverted arcuate path of a pilot string occupying a pilot hole underlying the obstacle. The pilot hole spans the obstacle from a first position at or near ground level on one side of the obstacle to a second position at or near ground level on the other side. An oversized casing having an inner diameter greater than the outer diameter of the production casing is first advanced into and partially along the pilot hole from one side of the obstacle. The oversized casing is advanced along the path of the pilot hole until it becomes frozen in place or is substantially impeded typically by friction.

Abstract: A frusto-conical multi-stage reamer constructed from a sequence of reamer stages is disclosed. Each reamer stage includes a central stem having a coupling at the leading end and a coupling at the trailing end. A plurality of circumferential arms extend from the central stem of each reamer stage and are inclined in a common direction with respect to the axis of the stems. The free ends of the arms are directed outwardly and forwardly with respect to the stem, and individual reamer teeth are attached to the free end of each arm. The radial extent of the arms of each stage of the sequence is a preselected increment greater than the radial extent of the arms of each preceding stage. In operation, the reamer stages are connected in sequence by the aforesaid couplings and simultaneously rotated and pulled through a pilot hole to produce an enlarged aperture.