Constant mass gas extraction for gas evaluation during drilling

Abstract

The present disclosure relates to a fluid evaluation system, including: a pump configured to receive drilling fluid that includes formational fluid from a drilling tool and pump the drilling fluid downstream within the evaluation system; a mass flow meter coupled to the output of the pump, the mass flow meter configured to provide a feedback signal to the pump to adjust one or more parameters of the pump such that a constant mass of the drilling fluid is pumped through the pump; a gas extractor coupled to the output of the mass flow meter, the gas extractor configured to separate gas from the drilling fluid; and a gas analytic detector coupled to the output of the gas extractor, the gas analytic detector configured to receive the gas and identify one or more characteristics of the gas.

What is claimed is: 
     
         1 . A system comprising:
 a downhole drilling tool for drilling a wellbore including a plurality of formations, the drilling tool configured to obtain a formational fluid from the wellbore;   a fluid evaluation system, including:
 a pump configured to receive drilling fluid that includes the formational fluid from the drilling tool and pump the drilling fluid downstream within the evaluation system; 
 a mass flow meter coupled to the output of the pump, the mass flow meter configured to provide a feedback signal to the pump to adjust one or more parameters of the pump such that a constant mass of the drilling fluid is pumped through the pump; 
 a gas extractor coupled to the output of the mass flow meter, the gas extractor configured to separate gas from the drilling fluid; and 
 a gas analytic detector coupled to the output of the gas extractor, the gas analytic detector configured to receive the gas and identify one or more characteristics of the gas. 
   
     
     
         2 . The system of  claim 1 , further comprising:
 a carrier gas source coupled to the gas extractor, the carrier gas source providing a carrier gas to the gas extractor to maintain a constant mass of the gas provided to the gas analytic detector by the gas extractor.   
     
     
         3 . The system of  claim 2 , wherein a pressure of the gas extractor is based on a mass flow rate of the carrier gas provided by the carrier gas source. 
     
     
         4 . The system of  claim 3 , further comprising:
 a pressure sensor coupled to the output of the gas extractor, the pressure sensor configured to provide a signal to the carrier gas source to adjust the mass flow rate of the carrier gas provided by the carrier gas source to the gas extractor.   
     
     
         5 . The system of  claim 1 , wherein the one or more parameters includes a mass flow rate. 
     
     
         6 . The system of  claim 5 , wherein the mass flow rate is based on a mass of the formational fluid obtained by the drilling tool. 
     
     
         7 . The system of  claim 5 , wherein the mass flow rate is based on a ratio of a mass of the drilling fluid to be analyzed to a mass flow rate of the formational fluid within the wellbore. 
     
     
         8 . The system of  claim 1 , further comprising a process heater coupled between the pump and the gas extractor, the process heater configured to increase a temperature of the drilling fluid toward a predetermined set point. 
     
     
         9 . The system of  claim 1 , further comprising:
 an additional pump coupled between the gas extractor and the drilling tool, the additional pump configured to pump the separated drilling fluid to the drilling tool.   
     
     
         10 . The system of  claim 9 , the mass flow meter further configured to provide an additional feedback signal to the additional pump to adjust one or more parameters of the additional pump such that a constant mass of the separated drilling fluid is pumped through the additional pump. 
     
     
         11 . A system comprising:
 a downhole drilling tool for drilling a wellbore including a plurality of formations, the drilling tool configured to obtain a formational fluid from the wellbore;   a fluid evaluation system, including:
 a mass flow meter configured to receive drilling fluid that includes the formational fluid from the drilling tool; 
 a pump coupled to the output of the mass flow meter, the pump configured to pump the drilling fluid downstream within the evaluation system; 
 a gas extractor coupled to the output of the pump, the gas extractor configured to separate gas from the drilling fluid; and 
 a gas analytic detector coupled to the output of the gas extractor, the gas analytic detector configured to receive the gas to identify one or more characteristics of the gas, 
   wherein the mass flow meter is configured to provide a feedforward signal to the pump to adjust one or more parameters of the pump such that a predetermined constant mass of the drilling fluid is pumped through the pump.   
     
     
         12 . The system of  claim 11 , further comprising:
 a carrier gas source coupled to the gas extractor, the carrier gas source providing a carrier gas to the gas extractor to maintain a constant mass of the gas provided to the gas analytic detector by the gas extractor.   
     
     
         13 . The system of  claim 12 , wherein a pressure of the gas extractor is based on a mass flow rate of the carrier gas provided by the carrier gas source. 
     
     
         14 . The system of  claim 13 , further comprising:
 a pressure sensor coupled to the output of the gas extractor, the pressure sensor configured to provide a signal to the carrier gas source to adjust the mass flow rate of the carrier gas provided by the carrier gas source to the gas extractor   
     
     
         15 . The system of  claim 11 , wherein the one or more parameters includes a mass flow rate. 
     
     
         16 . The system of  claim 15 , wherein the mass flow rate is based on a mass of the formational fluid obtained by the drilling tool. 
     
     
         17 . The system of  claim 15 , wherein the mass flow rate is based on a ratio of a mass of the drilling fluid to be analyzed to a mass flow rate of the formational fluid within the wellbore. 
     
     
         18 . A method, comprising:
 obtaining, by a downhole drilling tool, formational fluid from a wellbore;   pumping, by a pump, drilling fluid that includes the formational fluid downstream through a fluid evaluation system;   separating, by a gas extractor, gas from the drilling fluid that is pumped;   analyzing, by a gas analytic detector, the dissolved gas to identify one or more characteristics of the dissolved gas; and   providing, by a mass flow meter, a signal to the pump to adjust one or more parameters of the pump such that a constant mass of the drilling fluid is pumped through the pump.   
     
     
         19 . The method of  claim 18 , wherein the signal is a feedforward signal. 
     
     
         20 . The method of  claim 18 , wherein the signal is a feedback signal.