초록 ▼

Information is conveyed from a downhole location within a wellbore being drilled by producing pressure and velocity of flow variations from the steady state drilling fluid pressure and velocity of flow so as to set up transient acoustic waves that propagate to the surface through the drilling fluid

Information is conveyed from a downhole location within a wellbore being drilled by producing pressure and velocity of flow variations from the steady state drilling fluid pressure and velocity of flow so as to set up transient acoustic waves that propagate to the surface through the drilling fluid within the drill string. The acoustic waves are detected at the surface to obtain the propagated information. According to this invention, a simple and reliable method of recovering the propagated information is to monitor the pressure of the gas filled side of the accumulator or desurger device that is coupled to the drilling fluid line adjacent the pump.

대표청구항 ▼

In apparatus transmitting signals from within a well bore to the surface, and for detecting such signals, there being a drill pipe string and rotary bit means in the well bore, the combination comprising (a) first means for supplying a stream of drilling fluid to the drill pipe string for flow downw

In apparatus transmitting signals from within a well bore to the surface, and for detecting such signals, there being a drill pipe string and rotary bit means in the well bore, the combination comprising (a) first means for supplying a stream of drilling fluid to the drill pipe string for flow downwardly in the bore as a down stream, said first means including a flow line and a fluid pump connected with said line and operable to pressurize said drilling fluid, (b) structure in the well bore and to which said drill string is connected for passing drilling fluid to the bit means, the fluid then flowing back up the well bore in a return stream, (c) a first passage associated with said structure for diverting flow of some of the drilling fluid, and a valve associated with said structure and operable to interruptedly control flow of diverted fluid, via said passage, thereby to produce pulses in said down stream, the pulses traveling upwardly to fluid in said line, and characterized as providing acoustic particle velocity changes, (d) an instrument associated with said valve, in the bore, for controlling said operation of the valve as a function of data to be transmitted to the surface, (e) an accumulator connected with said line and defining a chamber into which said pulses are transmitted, the accumulator including a diaphragm in said chamber, one side of the diaphragm contacted by said fluid, and there being second fluid at the opposite side of the diaphragm and to which said pulses are transmitted via the diaphragm, the diaphragm movable to different positions in the chamber in response to operation of the pump, (f) the pump producing pulsations in the drilling fluid in the line between the pump and the accumulator and at a first pulsation frequency f1, the accumulator filtering said pulsations to reduce their amplitudes in the drilling fluid between the accumulator and the bit means, the valve operating to produce said pulses having a second frequency or frequencies substantially greater than f1 in the drilling fluid between the valve and the accumulator, (g) and a first pressure tranducer located to detect said pulses in the second fluid, irrespective of the position of the diaphragm in response to operation of the pump, (h) the accumulator and transducer together providing a means for converting changes in acoustic particle velocity into pressure changes.