Bore plug analysis system

Abstract

A method can include receiving pressure data with respect to time acquired via a pressure sensor disposed in an uphole region of a bore of a well, where a plug is disposed in the bore to define the uphole region to one side of the plug and a corresponding downhole region to the other side of the plug; using physical properties of liquid in the uphole region and thermal information, computing a temperature induced density variation of the liquid in the uphole region; and, based at least in part on at least a portion of the pressure data and the temperature induced density variation of the liquid, determining a state of the plug and the bore from a plurality of states.

What is claimed is: 
     
         1 . A method comprising:
 receiving pressure data with respect to time acquired via a pressure sensor disposed in an uphole region of a bore of a well, wherein a plug is disposed in the bore to define the uphole region to one side of the plug and a corresponding downhole region to the other side of the plug;   using physical properties of liquid in the uphole region and thermal information, computing a temperature induced density variation of the liquid in the uphole region; and   based at least in part on at least a portion of the pressure data and the temperature induced density variation of the liquid, determining a state of the plug and the bore from a plurality of states.   
     
     
         2 . The method of  claim 1 , wherein the plurality of states comprise a no leakage state and a leakage state. 
     
     
         3 . The method of  claim 1 , comprising determining presence of liquid or liquid and gas in the uphole region and, responsive to the presence of liquid or liquid and gas, selecting a relationship for computing the temperature induced density variation of the liquid or of the liquid and gas in the uphole region. 
     
     
         4 . The method of  claim 3 , comprising determining presence of liquid communication with atmospheric pressure or gas communication with atmospheric pressure. 
     
     
         5 . The method of  claim 1 , comprising determining a presence of one of: gas in a portion of the uphole region uphole the liquid wherein the gas is in pressure communication with atmosphere; gas in a portion of the uphole region uphole the liquid wherein the gas is not in pressure communication with atmosphere; and the liquid extending to a top of the uphole region without a separate gas region therein wherein the liquid is not in pressure communication with atmosphere. 
     
     
         6 . The method of  claim 5 , comprising responsive to the determining, selecting a relationship that relates at least a portion of the pressure data to flow rate. 
     
     
         7 . The method of  claim 1 , wherein, in a leakage state of the plug and the bore, a height parameter of the liquid in the uphole region is a function with respect to time. 
     
     
         8 . The method of  claim 1 , wherein a height of the liquid in the uphole region is more than ten times greater than a height of the plug. 
     
     
         9 . The method of  claim 1 , comprising determining that gas exists in a portion of the uphole region that is uphole from the liquid in the uphole region. 
     
     
         10 . The method of  claim 9 , comprising using physical properties of the gas and at least a portion of the thermal information, computing an environmentally induced density variation of the gas in the portion of the uphole region. 
     
     
         11 . The method of  claim 10 , wherein the computing an environmentally induced density variation comprises accounting for pressure effect on the gas in the portion of the uphole region. 
     
     
         12 . The method of  claim 1 , comprising assessing the temperature information for a temperature gradient. 
     
     
         13 . The method of  claim 1 , comprising estimating pressure with respect to time for the downhole region proximate to the plug. 
     
     
         14 . The method of  claim 1 , comprising estimating a flow rate from the downhole region to the uphole region using a computed relationship and at least a portion of the pressure data. 
     
     
         15 . The method of  claim 14 , wherein the computed relationship comprises a slope that relates pressure and flow rate. 
     
     
         16 . The method of  claim 15 , wherein the slope is: 
       
         
           
             
               C 
               = 
               
                 
                   
                     
                       k 
                       p 
                     
                     ⁢ 
                     
                       a 
                       p 
                     
                   
                   
                     μ 
                     ⁢ 
                     
                       l 
                       p 
                     
                   
                 
                 . 
               
             
           
         
       
     
     
         17 . The method of  claim 1 , comprising utilizing a relationship of pressure with respect to time versus a height parameter with respect to time for the liquid in the uphole region. 
     
     
         18 . The method of  claim 17 , comprising determining the height parameter with respect to time for the liquid in the uphole region using at least a portion of the pressure data, wherein the relationship is represented as: 
       
         
           
             
               
                 
                   P 
                   t 
                 
                 ⁢ 
                     
                 versus 
                 ⁢ 
                     
                 
                   dh 
                   dt 
                 
               
               + 
               
                 
                   β 
                   
                     ρ 
                     
                       ℓ 
                       ⁢ 
                       t 
                     
                   
                 
                 ⁢ 
                 h 
                 ⁢ 
                 
                   dh 
                   dt 
                 
               
             
           
         
       
       and wherein the relationship comprises an intercept, represented as:
     P   b0   −     gl   p . 
 
     
     
         19 . A system comprising:
 a processor;   memory accessible by the processor;   processor-executable instructions stored in the memory and executable to instruct the system to:
 receive pressure data with respect to time acquired via a pressure sensor disposed in an uphole region of a bore of a well, wherein a plug is disposed in the bore to define the uphole region to one side of the plug and a corresponding downhole region to the other side of the plug; 
 using physical properties of liquid in the uphole region and thermal information, compute a temperature induced density variation of the liquid in the uphole region; and 
 based at least in part on at least a portion of the pressure data and the computed temperature induced density variation of the fluid, determine a state of the plug and the bore from a plurality of states. 
   
     
     
         20 . One or more computer-readable storage media comprising processor-executable instructions to instruct a computing system to:
 receive pressure data with respect to time acquired via a pressure sensor disposed in an uphole region of a bore of a well, wherein a plug is disposed in the bore to define the uphole region to one side of the plug and a corresponding downhole region to the other side of the plug;   using physical properties of liquid in the uphole region and thermal information, compute a temperature induced density variation of the liquid in the uphole region; and   based at least in part on at least a portion of the pressure data and the computed temperature induced density variation of the fluid, determine a state of the plug and the bore from a plurality of states.