Abstract: A replaceable stud cutter for use in matrix drag bit is provided by furnacing a ductile metallic receptacle within the body of the drag bit as it is fabricated. The metal receptacle is characterized by having a receiving cavity defined therein and by including various mechanisms such as grooves or flares which facilitate retention of the metallic receptacle within the matrix body. The lowermost portion of the receptacle within the matrix body may also be shaped or tapered to allow dense packing of the receptacle adjacent to other receptacles along a given radial line on the bit face. A replaceable cutter is brazed, adhesively bonded and/or mechanically locked within the receiving cavity defined in the metal receptacle. When the replaceable cutter becomes worn through normal use, the mechanical locking elements can be drilled out, the brazing melted or adhesive dissolved to allow insertion of a new replacement cutter without causing any damage or alteration either to the receptacle, matrix body or bit face.

Abstract: A tool face orientation of a directional drill bit within a borehole is efficiently communicated to the well surface by communicating only changes in the tool face orientation. In the first embodiment after the entire tool face orientation is measured and transmitted uphole, and thereafter changes of the tool face orientation as measured with respect to the center of spatially fixed sectorial ranges are transmitted uphole. The magnitude of the changes relative to the center of a fixed sectorial range, being smaller than the range of the entire tool face orientation, allow the subsequent transmission to be made using words of shorter length. Alternatively, the changes in tool face orientation may be measured with respect to a sliding reference point. The sliding reference point may, for example, be the mean value of the prior ten measurements and any previous mean values.

Abstract: An in-situ linear flow proppant conductivity test cell is provided which allows a downhole fracturing operation to be accurately simulated under laboratory conditions. The test apparatus includes a housing, having pistons therein, a plurality of heating elements, and a packer with a plurality of ports therethrough. Core samples are inserted into the test apparatus and a proppant bed, such as a sand slurry, is introduced into the test cell between the core samples. An external press then provides pressure to the pistons simulating the overburden experienced downhole, while the heating elements simulate downhole temperatures. Pressure, differential pressure, flow rate temperature and fluid loss characteristics can then be measured through the plurality of ports within the packer.

Abstract: A format conversion system for use in digital systems converts digital data words from a fixed point format to a floating point format and vice versa. A two's complement circuit tests the sign bit of a first fixed point digital data word and provides the complement if the word is negative. A code establishing circuit receives the first fixed point digital data word or its complement, detects the number of O's to the left of the most significant one bit and establishes a first code representative thereof. A second code establishing circuit receives the exponent of a first floating point digital data word and provides a second code representative thereof. A mantissa/fixed point determining circuit receives either the first fixed point digital data word, or the mantissa in reverse order, of the first floating point digital data word.

Abstract: A method of well testing, including treating, whereby a testing string including a tool bore closure valve is run into the well bore with the valve in an open mode, the string may be automatically filled, a packer may be pressure tested without cycling the tool bore closure valve, and fluids may be spotted into the testing string, displacing wellbore fluids from the bottom of the testing string, prior to running the test.