초록 ▼

An apparatus includes a helical flow tube in a formation testing tool. A current injector injects an electromagnetic current into the flow tube. A receiver coil is positioned to produce a receiver coil signal in response to the electromagnetic current. A processor is coupled to the receiver coil to

An apparatus includes a helical flow tube in a formation testing tool. A current injector injects an electromagnetic current into the flow tube. A receiver coil is positioned to produce a receiver coil signal in response to the electromagnetic current. A processor is coupled to the receiver coil to calculate a conductivity of a fluid flowing through the flow tube based on the receiver coil signal.

대표청구항 ▼

1. An apparatus comprising: a helical flow tube in a formation testing tool;a current injector to inject an electromagnetic current into the flow tube, wherein the current injector has two electrodes that extend into the flow tube;a receiver coil positioned to produce a receiver coil signal in respo

1. An apparatus comprising: a helical flow tube in a formation testing tool;a current injector to inject an electromagnetic current into the flow tube, wherein the current injector has two electrodes that extend into the flow tube;a receiver coil positioned to produce a receiver coil signal in response to the electromagnetic current; anda processor coupled to the receiver coil to calculate a conductivity of a fluid flowing through the flow tube based on the receiver coil signal;wherein the processor calculates the conductivity of the fluid flowing through the flow tube as a measurement of the receiver coil signal in a complex domain multiplied by a real valued tool constant after a tool body signal is subtracted. 2. The apparatus of claim 1 wherein: the receiver coil comprises a coil of wire in an insulating liner. 3. The apparatus of claim 1 further comprising: a measurement circuit to receive the receiver coil signal; andthe measurement circuit to provide to the processor: an amplitude signal representing the amplitude of the receiver coil signal; anda phase signal representing the phase of the receiver coil signal. 4. An apparatus comprising: a helical flow tube in a formation testing tool;exactly one transmitter coil;a receiver coil;a resistance measurement device to measure a resistance of a fluid flowing through the flow tube; anda processor;wherein the transmitter coil, receiver coil, and processor are interconnected in such a way that the processor can calculate a conductivity of a fluid flowing through the helical flow tube,wherein the transmitter coil and the receiver coil are a conductance measurement device to measure a conductance of the fluid flowing through the flow tube, andwherein the processor reports a measurement of the resistance measurement device when the resistance of the fluid flowing through the flow tube is above a resistance threshold, and reports a measurement of the conductance measurement device when the conductance of the fluid flowing through the flow tube is above a conductance threshold. 5. The apparatus of claim 4 wherein: the receiver coil comprises a coil of wire in an insulating liner. 6. The apparatus of claim 4 wherein: the transmitter coil is coaxial with the receiver coil. 7. The apparatus of claim 4 wherein: the processor reporting the measurement by the conductance measurement device of the conductance, σ, of the fluid includes the processor calculating: σ=VK,where: V is a voltage measured at the receiver coil, K=NT⁢NR⁢IT⁡(π⁢⁢a2)2⁢ω2⁢μ24⁢π⁢⁢L,NT is the number of turns in the transmitter coil,NR is the number of turns in the receiver coil,It and ω are the amplitude and angular frequency, respectively, of a time harmonic current generated in the transmitter coil,a is the radius of the transmitter coil and the receiver coil,μ is the permeability of the formation, andL is the distance between transmitter coil and the receiver coil. 8. The apparatus of claim 4 wherein: the processor reporting the measurement by the resistance measurement device of the resistance, ρ, of the fluid, includes the processor calculating: ρ=RG,where: R=IV,V is the voltage measured across a first electrode and a second electrode inserted in the fluid,I is the current measured flowing through the fluid between the first electrode and the second electrode, andG is a geometry factor determined during a calibration of the resistance measurement device. 9. The apparatus of claim 4 wherein: the resistance measurement device comprises an electrode extending into the flow tube. 10. A method comprising: inductively generating an inductively-generated current flow in a fluid in a flow tube using a first inductive device;inductively measuring the inductively-generated current flow using a second inductive device;resistively generating a resistively-generated current flow in the fluid using a resistive generator;resistively measuring the resistively-generated current flow using a resistive sensor;calculating with a processor in a downhole tool interconnected with the first inductive device and the second inductive device a conductivity of the fluid using the inductively measured current;calculating with the processor interconnected with the resistive generator and the resistive sensor the resistivity of the fluid using the resistively measured current; andwherein the processor reports the calculated resistivity when the calculated resistivity is above a resistance threshold and reports the calculated conductivity when the calculated conductivity is above a conductance threshold.