System and method for monitoring water contamination when performing subterranean operations

Abstract

A method and system for monitoring groundwater quality at or near a wellbore are disclosed. A monitoring sensor is coupled to the groundwater and detects at least one characteristic of the groundwater. The monitoring sensor is a Multivariate Optical Computer (“MOC”) and is optically coupled to the groundwater

What is claimed is: 
     
         1 . A system for monitoring at least one characteristic of groundwater in a subterranean formation comprising:
 a monitoring sensor coupled to the groundwater, wherein the monitoring sensor is operable to detect at least one characteristic of the groundwater, wherein the monitoring sensor is a Multivariate Optical Computer (“MOC”) and wherein the MOC is optically coupled to the groundwater.   
     
     
         2 . The system of  claim 1 , wherein the at least one characteristic is selected from a group consisting of chemical composition, pH, temperature, viscosity, density, ionic strength, total dissolved solids, salt content, porosity, opacity, bacteria content, hydrocarbon concentration, salt concentration, ion concentration, mud fluid concentration, fracking fluid concentration, tracer concentration, and a combination thereof. 
     
     
         3 . The system of  claim 1 , wherein coupling the monitoring sensor to the groundwater interval comprises at least one of placing the monitoring sensor in the wellbore proximate to the groundwater interval and coupling the monitoring sensor to a side string wherein the side string is fluidically coupled to the groundwater interval. 
     
     
         4 . The system of  claim 3 , wherein the MOC is battery operated. 
     
     
         5 . The system of  claim 1 , wherein the monitoring sensor notifies an operator if the at least one characteristic exceeds a threshold value. 
     
     
         6 . A method for monitoring ground fluids when performing subterranean operations comprising:
 drilling a wellbore in a subterranean formation,
 wherein the wellbore traverses one or more strata of the subterranean formation, and 
 wherein at least one of the one or more strata of the subterranean formation comprises a groundwater interval; 
   coupling a monitoring sensor to the groundwater interval,
 wherein coupling the monitoring sensor to the groundwater interval comprises at least one of placing the monitoring sensor in the wellbore proximate to the groundwater interval and coupling the monitoring sensor to a side string wherein the side string is fluidically coupled to the groundwater interval; and 
   detecting at least one characteristic of the groundwater interval using the monitoring sensor.   
     
     
         7 . The method of  claim 6 , wherein coupling the monitoring sensor to the groundwater interval comprises providing a perforation into the groundwater interval, wherein fluid from the groundwater interval flows to the monitoring sensor through the perforation. 
     
     
         8 . The method of  claim 7 , further comprising fluidically coupling a side string to the perforation and the monitoring sensor, wherein the monitoring sensor is detachably attached to the side string. 
     
     
         9 . The method of  claim 6 , further comprising placing a casing in the wellbore, wherein the monitoring sensor is positioned in an annulus between the casing and the wellbore. 
     
     
         10 . The method of  claim 6 , further comprising selectively turning the monitoring sensor on and off to detect the at least one characteristic of the groundwater interval using the monitoring sensor. 
     
     
         11 . The method of  claim 6 , wherein the monitoring sensor is optically coupled to the groundwater interval. 
     
     
         12 . The method of  claim 6 , wherein the monitoring sensor is a Multivariate Optical Computer (“MOC”). 
     
     
         13 . The method of  claim 6 , wherein the monitoring sensor notifies an operator if the at least one characteristic exceeds a threshold value. 
     
     
         14 . The method of  claim 6 , wherein the at least one characteristic is selected from a group consisting of chemical composition, pH, temperature, viscosity, density, ionic strength, total dissolved solids, salt content, porosity, opacity, bacteria content, hydrocarbon concentration, salt concentration, ion concentration, mud fluid concentration, fracking fluid concentration, tracer concentration, and a combination thereof. 
     
     
         15 . A method for monitoring a characteristic of groundwater intervals corresponding to a plurality of wellbores comprising:
 drilling a first wellbore adjacent to a first groundwater interval;   optically coupling a first monitoring sensor to the first groundwater interval;   drilling a second wellbore adjacent to a second groundwater interval;   optically coupling a second monitoring sensor to the second groundwater interval,   wherein at least one of the first monitoring sensor and the second monitoring sensor is a Multivariate Optical Computer (“MOC”);   communicatively coupling the first monitoring sensor and the second monitoring sensor to a central information handling system;   monitoring a characteristic in the first groundwater interval using the first monitoring sensor; and   monitoring a characteristic in the second groundwater interval using the second monitoring sensor.   
     
     
         16 . The method of  claim 15 , further comprising at least one of providing a visual rendering of data received from the first monitoring sensor and the second monitoring sensor and notifying an operator of potential contamination at the central information handling system. 
     
     
         17 . The method of  claim 15 , wherein at least one of the characteristic in the first groundwater interval and the characteristic in the second groundwater interval is selected from a group consisting of chemical composition, pH, temperature, viscosity, density, ionic strength, total dissolved solids, salt content, porosity, opacity, bacteria content, hydrocarbon concentration, salt concentration, ion concentration, mud fluid concentration, fracking fluid concentration, tracer concentration, and a combination thereof. 
     
     
         18 . The method of  claim 15 , further comprising selectively turning at least one of the first monitoring sensor and the second monitoring sensor on and off to monitor the characteristic in the first groundwater interval and the characteristic in the second groundwater interval. 
     
     
         19 . The method of  claim 15 , wherein at least one of the first monitoring sensor and the second monitoring sensor is battery operated. 
     
     
         20 . The method of  claim 15 , wherein the central information handling system notifies an operator if at least one of the characteristic of the first groundwater interval and the characteristic of the second groundwater interval exceeds a threshold value.