Abstract: Apparatus for controlling the operation of drilling or completion fluid pumps and a choke is disclosed. Control over the drilling or completion fluid pump can be independent of control of the choke. Control over the drilling fluid pump can be transferred to the choke control location. Pneumatic and electrical networks suitable for use with engine driven and electrically powered rigs are disclosed.

Abstract: Apparatus and method for detecting the level of gases entrained within a circulating drilling fluid used in subterranean well operations are disclosed. Detection of incipient gas kicks during drilling operations is accomplished by detecting the level of entrained gases. A gas-air sample is gathered at the surface of the well, and a gas-air sample having a constant relative humidity is delivered at a constant volumetric flow rate to gas sensors. Dilution air is automatically added to the sample when the gas concentration exceeds a known limit. Automatic periodic calibration of the sensors is provided. Stable signals from the gas sensor are obtained at two distinct flow rates.

Abstract: An apparatus for measuring tension in cables or chains comprises a unitary structure which may be entirely formed by welding and bending operations. An elongated resiliently deformable rod has its opposed ends bent laterally in opposite directions into hook-shaped formations to engage a section of a cable in which the tension is to be measured, causing the cable to assume a non-linear, generally helical configuration when the apparatus is assembled thereto. An adjustable height pad may be attached to the center of the bar to engage the cable and increase its helical angle. An indicator bar, having indications provided thereon, is disposed in generally radial relationship to the rod adjacent one end thereof. A cantilever pointer has one end welded to the rod remote from the indicating bar and the pointed end disposed adjacent the indicating bar.