Logging device for measuring pressure into an underground formation and associated method

Abstract

The invention relates to a logging device for measuring pressure into an underground formation, comprising at least one formation pressure sensor which comprises a tool body part and a probe mounted on the tool body part, said probe comprising a fluid withdrawal line. The tool body part comprises a flow line connected to the fluid withdrawal line, at least one test chamber connected to the flow line and an at least one respective closing system, and at least one pressure sensor connected to the flow line. The probe further comprises a rupture chamber and a pressure sensor connected to the fluid withdrawal line and, a first isolating valve on the fluid withdrawal line downstream of the rupture chamber and upstream to the flow line adapted to isolate the rupture chamber from the flow line when the rupture chamber is actuated.

1 . A logging device for measuring pressure into an underground formation containing a fluid, said logging device comprising:
 at least one formation pressure sensor, said formation pressure sensor comprising a tool body part and a probe mounted on the tool body part, said probe comprising a fluid withdrawal line intended to be placed in fluid communication with the underground formation after rupture of a mud cake, the tool body part comprising a flow line connected to the fluid withdrawal line, several parallel test chambers connected to the flow line and several respective closing systems adapted to fluidly isolate each test chamber from the flow line, and at least one pressure sensor connected to the flow line,   wherein the probe further comprises a rupture chamber intended to be actuated to rupture the mud cake by suction and a pressure sensor connected to the fluid withdrawal line and, a first isolating valve on the fluid withdrawal line downstream of the rupture chamber and upstream to the flow line adapted to isolate the rupture chamber from the flow line when the rupture chamber is actuated.   
     
     
         2 . The logging device according to  claim 1 , wherein the probe further comprises a second isolating valve different from the first isolating valve between the rupture chamber and the fluid withdrawal line adapted to isolate the rupture chamber from the fluid withdrawal line when at least one of test chambers is actuated, or wherein the first isolating valve is a three-way valve connected to the fluid withdrawal line adapted to isolate the rupture chamber from the fluid withdrawal line when at least one of the test chambers is actuated. 
     
     
         3 . The logging device according to  claim 2 , further comprising a control unit adapted to actuate the rupture chamber, the first isolating valve and the second isolating valve, at least one of the closing systems and at least one of the test chambers between a first mud cake rupturing configuration wherein the first isolating valve is closed, the second isolating valve is opened and the rupture chamber is actuated and a second configuration wherein the first isolating valve is opened, the second isolating valve is closed, at least one of the closing systems are opened and at least one of the test chambers is actuated, or wherein the logging device further comprises a control unit adapted to actuate the rupture chamber, the three-way valve, at least one of the closing system and at least one of the test chambers between a first mud cake rupturing configuration wherein the three-way valve allows only the fluid circulation between the rupture chamber and the first end of the fluid withdrawal line and the rupture chamber is actuated, and a second configuration wherein the three-way valve allows only the fluid circulation between the first end of the fluid withdrawal line and the flow line, at least one of the closing systems is opened and at least one of the test chambers is actuated. 
     
     
         4 . The logging device according to  claim 1 , wherein the volume of each of the test chambers is more than the volume of the rupture chamber. 
     
     
         5 . The logging device according to  claim 1 , wherein the rupture chamber defines a cavity and comprises a piston movable into the cavity between a retracted position and an extended position. 
     
     
         6 . The logging device according to  claim 1 , further comprising a plurality of different sensors and a processing unit, said sensors being configured to provide measurements to the processing unit, said processing unit being configured to process said measurements to determine at least a value of a physical parameter of the environment of the logging device and at least a redundant value of the same physical parameter of the environment of the logging device, the value and the redundant value being determined from at least two different sensors measurements measuring different physical parameters. 
     
     
         7 . The logging device according to  claim 6 , wherein the plurality of different sensors are chosen among a plurality of formation pressure sensors at different heights, a plurality of hydrostatic well pressure sensors at different heights, a gradio-manometer sensor, a gamma-ray sensor, a cable tension sensor and/or an inclinometer sensor. 
     
     
         8 . The logging device according to  claim 6 , wherein at least one first sensor of the plurality of sensors is configured to provide at least one direct measurement of a value of a physical parameter of the environment of the logging device to the processing unit and the processing unit is configured to calculate at least one redundant value of the same physical parameter through the measurements of at least a second sensor among the plurality of sensors, the second sensor measuring a physical parameter of the environment of the logging device different from the physical parameter of the environment of the logging device measured by the first sensor. 
     
     
         9 . The logging device according to  claim 6 , further comprising a computation unit configured to calculate an uncertainty and/or a coherence of the at least one physical parameter of the environment of the logging device, based on the at least one value of the physical parameter and on the at least one redundant value of the same physical parameter obtained from the at least two different sensors. 
     
     
         10 . The logging device according to  claim 6 , further comprising a communication unit configured to communicate the uncertainty and/or the coherence of the at least one physical parameter to an operator. 
     
     
         11 . The logging device according to  claim 6 , further comprising an automatic control unit configured to control at least one of the test chambers and/or the rupture chamber, said automatic controlling unit being connected to the computation unit and/or to the processing unit in order to adjust the parameters of fluid suction of at least one of the test chambers and/or the parameters of the rupture chamber based on the measurements of at least one sensor, on the at least one value and the at least one redundant value of at least one physical parameter and/or based on an uncertainty and/or a coherence of the physical parameter obtained from the at least two different sensors. 
     
     
         12 . A method for measuring pressure into an underground formation containing a fluid using a logging device according to  claim 1 , comprising the following steps:
 putting the probe in contact with a mud cake of the underground formation,   closing the first isolating valve,   actuating the rupture chamber so as to establish fluid communication between the underground formation and the fluid withdrawal line by rupturing the mud cake,   opening the first isolating valve,   actuating at least one of the test chambers so as to suction fluid inside the at least one of the test chambers,   ensuring fluid isolation of the at least one of the test chambers from the flow line by closing the respective at least one of the closing systems of the at least one of the test chambers,   measuring the pressure stabilization in the flow line.   
     
     
         13 . The method according to  claim 12 , further comprising a step of closing a second isolating valve different from the first isolating valve between the rupture chamber and the fluid withdrawal line, to isolate the rupture chamber from the fluid withdrawal line before opening the first isolating valve, or wherein the first isolating valve is a three-way valve connected to the fluid withdrawal line, the method comprising a step of actuating the three-way valve to isolate the rupture chamber from the fluid withdrawal line before actuating the at least one of the test chambers. 
     
     
         14 . The method according to  claim 12 , further comprising a step of acquiring measurements with a plurality of sensors and processing said measurements to determine at least a value of a physical parameter of the environment of the logging device and at least a redundant value of the same physical parameter of the environment of the logging device, the value and the redundant value being determined from at least two different sensors measurements measuring different physical parameters. 
     
     
         15 . The method according to  claim 14 , further comprising a step of computing an uncertainty and/or a coherence of the at least one physical parameter by the calculation unit based on the at least one value of the physical parameter and on the at least one redundant value of the physical parameter obtained from the at least two different sensors. 
     
     
         16 . The method according to  claim 15 , further comprising a step of communicating the uncertainty and/or the coherence of the at least one physical parameter to an operator by the communication unit. 
     
     
         17 . The method according to  claim 14 , further comprising a step of automatic controlling of the at least one of the test chambers and/or the rupture chamber so as to adjust the parameters of fluid suction of the at least one of the test chambers and/or the parameters of the rupture chamber based on the measurements of the at least one sensor, based on the at least one value and the at least one redundant value of at least one physical parameter and/or based on an uncertainty and/or a coherence of the physical parameter obtained from the at least two different sensors.