Abstract: A drilling tool connected in a drilling string includes a pressure responsive rotatable ball valve for enabling drilling fluid flow down the bore of a drill string which automatically rotates closed for blocking flow through the bore of the drill string when incipient pressure conditions indicate the direction of flow through the bore may be reversed. Means for releasably locking the ball in the open position in response to a preselected directional pressure to enable the running of other tools and the like through the bore of the drilling string are provided. The drilling tool may be employed for controlling an undesired flowing stream of fluid from the bore of the drilling string by stabbing the tool to connect with the drilling string utilizing a stabbing member which is removed after connecting to enable the ball valve to rotate closed to control the flowing stream.

Abstract: The gas content of well drilling mud under pressure is determined by extracting or isolating a sample of the pressurized mud, as for example at a down-hole location, reducing the pressure of the sample, and sensing the fluid pressure of the sample prior to and following such pressure reduction.