Structure (17) is passed into an earth well (10) including a whipstock (28) attached to piping (18) and a retractible anchor. The whipstock (28) includes a number of connected guide assemblies. Erection means is connected at one end to a forward guide assembly and at the other end to an extension projecting to the earth surface. To erect the whipstock, the extension is pulled to cause the guide assemblies to swing into a curved pathway. Thereafter, a drilling tube is passed through the whipstock into the formation. The whipstock may be deerected by releasing the extension means. Then, the anchor is released and the structure is pulled out.

A drilling system in which hydraulic forces are applied against a drillhead at the forward end of a drilling pipe to pull a pipe into underground formation. A pushing force also is applied from the rearward end using sliding seals and a closed rearward end of the drill string against which fluid pressure is applied, or (b) by providing a dead weight to the rearward end.

A system for gravel packing a production radial tube placed by the drilling system. The radial tube is perforated. A flexible permeable liner is passed into the radial tube and slurry is flowed through the liner and out the distal end of the radial tube back towards the well bore to form an annular gravel pack.

Probe and method for determining the curvature of an elongated opening such as a borehole in the earth. The probe includes an axially extending flexible shaft and two pairs of sensive wires arranged in the quadrature about the shaft for axial movement relative to each other upon bending of the probe. The relative axial positions of the sensing wires on opposite sides of the flexible shaft are monitored to determine the curvature of the borehold.

In cutting a downhole pipe in proximity to a closure in the pipe, the pipe is first perforated. A perforating torch is positioned with a pipe in proximity to the closure. The perforating torch produces cutting fluids in a first radial direction and produces an opening in the pipe, which cutting fluids produce a reaction force opposite to the first radial direction. This reaction force drives the perforating torch into contact with the pipe, anchoring it against any pressure wave produced by the cutting fluids and reflected off of the closure. Once the pipe is opened, a cutting torch is operated to sever the pipe. Any pressure wave generated by the cutting torch is vented through the opening.

A limited entry perforating phased gun system and method for accurate perforation in a deviated/horizontal wellbore is disclosed. The system/method includes a gun string assembly (GSA) deployed in a wellbore with shaped charge clusters. The charges are spaced and angled such that, when perforated, they intersect at a preferred fracturing plane. Upon fracturing, the fractures initiate at least principal stress location in a preferred fracturing plane perpendicular to the wellbore from an upward and downward location of the wellbore. Thereafter, the fractures connect radially about the wellbore in the preferred fracturing plane. The fracture treatment in the preferred fracturing plane creates minimal tortuosity paths for longer extension of fractures that enables efficient oil and gas flow rates during production.

A pressure equalization valve for a treatment tool (51) movable in a completion string (12). The valve comprises a cylindrical valve body having an axial bore (110) in fluid communication with the treatment tool (51). A cylindrical shuttle (112) is provided axially and sealably movable in the axial bore (110). The shuttle (112) is operable between a closed position and an open position. When a flow rate of the fluid flowing from the treatment tool (51) exceeds a preset rate to overcome the spring (114) biasing, the shuttle (112) shifts to the closed position. When the flow rate from the treatment tool (51) drops below the preset rate, the shuttle (112) is biased to the open position.