Abstract: A method is disclosed for logging a formation penetrated by an inclined or horizontal wellbore utilizing a conventioanl logging tool. A collar catcher assembly is attached to a lower portion of a drillstring and a collar is attached to an upper portion of a logging tool. The drillstring is lowered within the wellbore to a position adjacent the formation to be logged. The logging tool is transported through the drillstring until the collar thereon engages and is restrained by the catcher assembly. Then the formation is logged while the drillstring is withdrawn through the wellbore.

Abstract: A method of apparatus for controlling in a wellbore the force applied to a rotating drill bit of the type having fluid circulating through an opening in the lower end thereof. One aspect of the method comprises sensing the torque in the drill bit and varying the flow of the circulating fluid through the drill bit responsive to the torque. Apparatus is provided for maintaining constant torque in the drill bit by varying the fluid flow through the bit, which varies in turn the weight applied to the bit and therefore bit torque.

Abstract: A turbine for driving a drill bit includes means for locking the turbine rotor. A generally cylindrical locking assembly is connected to the rotor via a splined connection which permits relative axial movement of the locking assembly and rotor while restricting relative rotational movement thereof. A tab extends radially outwardly from the locking assembly and is receivable in an axial groove formed on the inner surface of the turbine case. When so received, rotational movement of the locking assembly and thus the rotor is prevented. An annular cavity is formed on the inner surface of the turbine case adjacent one end of the groove. When the tab is received therein, rotational movement of the locking assembly and rotor relative to the turbine case is permitted. A wellbore may be reamed and washed with the rotor in its locked condition by rotating the drill string as in conventional rotary drilling and circulating fluid.

Abstract: A method and apparatus for controlling the rotational torque of a drill bit powered by a downhole motor. The downhole motor is suspended from a hydraulic ram at the lower end of a string of drill pipe. A torque sensor detects the reactive torque in the downhole motor during drilling. In response to the detected torque level, pressurized drilling fluid from the downhole motor is provided to the hydraulic ram thereby varying the weight applied to the drill bit in order to maintain a constant torque level.

Abstract: An improved drill bit and a method for making the same. A body having an upper end is adapted for connection to a source of rotary motion. A curved surface formed on the lower end of the body includes a plurality of cutting elements embedded therein. A port provides drilling fluid between the curved surface and the bore during drilling. The cutting elements and fluid courses formed on the curved surface define a gap between the surface and the bore during drilling. The gap is formed to provide no more than a substantially linear reduction in drilling fluid pressure with increasing bit radius. In making the bit, a bottomhole pattern and a substantially constant flow area are selected. Dimensions of the lower drill bit surface are calculated to provide the selected flow area over the surface when the bit is in position above the bottomhole pattern.

Abstract: Apparatus for use within a well for indicating the difference in densities between two well fluids. The apparatus is formed within a drill collar with a source of radiation removably disposed in a wall of the drill collar. At least two radiation detectors are located equidistant from the source of radiation with one detector adjacent an interior central bore through the drill collar and a second detector is adjacent the exterior of the drill collar. Two fluid sample chambers are spaced between the source of radiation and the detectors, respectively; one chamber for diverting fluid from the bore and the other chamber for diverting fluid from the annular space between the drill bore and the drill collar. Suitable circuitry is connected to the detectors for producing a differential signal substantially proportional to the difference in radiation received at the two detectors.