Evaluating Wellbores For Use As Carbon Capture Underground Storage Wells

Abstract

A variety of methods and systems are disclosed, including, in one example, a method including: providing a composition for a cement disposed in a wellbore; selecting injection conditions for an invasive fluid for an injection or storage operation; predicting a depth of penetration of the invasive fluid into the cement with a depth of penetration model based at least in part on the injection conditions and the composition for the cement; predicting a material property of the cement with a cement property model based at least in part on the predicted depth of penetration; performing an integrity analysis based at least in part on the predicted material property; and performing the injection or storage operation in the wellbore based at least in part on the integrity analysis.

What is claimed is: 
     
         1 . A method comprising:
 providing a composition for a cement disposed in a wellbore;   selecting injection conditions for an invasive fluid for an injection or storage operation;   predicting a depth of penetration of the invasive fluid into the cement with a depth of penetration model based at least in part on the injection conditions and the composition for the cement;   predicting a material property of the cement with a cement property model based at least in part on the predicted depth of penetration;   performing an integrity analysis based at least in part on the predicted material property; and   performing the injection or storage operation in the wellbore based at least in part on the integrity analysis.   
     
     
         2 . The method of  claim 1 , wherein the injection conditions comprise at least one condition selected from the group consisting of a volumetric flow rate, temperature, pressure, volume, phase, concentration, and any combinations thereof. 
     
     
         3 . The method of  claim 2 , further comprising modifying at least one of the injection conditions based at least in part on the integrity analysis. 
     
     
         4 . The method of  claim 2 , further comprising repeating the steps of predicting a depth of penetration, predicting a material property, and performing an integrity analysis until an output of the integrity analysis satisfies a predetermined criteria. 
     
     
         5 . The method of  claim 2 , further comprising disposing a logging tool in the wellbore and performing a wellbore casing assessment prior to the injection or storage operation, wherein the injection or storage operation is performed if a sonic attenuation of the wellbore casing is below a threshold value. 
     
     
         6 . The method of  claim 1 , further comprising specifying a timespan, wherein the predicted depth of penetration is determined based at least in part on an exposure of the cement to the invasive fluid during the specified timespan. 
     
     
         7 . The method of  claim 6 , wherein predicting the material property of the cement is repeated using the cement property model for a plurality of time intervals within the specified timespan. 
     
     
         8 . The method of  claim 1 , wherein the injection or storage operation comprises injecting an injection fluid comprising the invasive fluid into a permeable zone of a subterranean formation, the injecting conforming to the selected injection conditions. 
     
     
         9 . The method of  claim 1 , wherein the integrity analysis is performed with a numerical simulator, wherein the injection or storage operation is performed if an output of the numerical simulator meets a predetermined criteria. 
     
     
         10 . The method of  claim 9 , wherein the output of the numerical simulator comprises strain at each of a plurality of depths and azimuths at or near the wellbore. 
     
     
         11 . The method of  claim 1 , wherein the integrity analysis comprises providing a maximum material property of the cement and comparing the maximum material property to the predicted material property. 
     
     
         12 . The method of  claim 1 , wherein the integrity analysis comprises comparing a load and a failure property of the cement. 
     
     
         13 . The method of  claim 1 , wherein the integrity analysis comprises comparing, for a plurality of regions at or near the wellbore, a maximum shear stress and an applied shear stress. 
     
     
         14 . The method of  claim 1 , wherein the depth of penetration model, the cement property model, or both comprise at least one algorithm selected from the group consisting of a supervised machine learning algorithm, a semi-supervised machine learning algorithm, an unsupervised machine learning algorithm, a reinforced machine learning model, a binary classification model, a multiclass classification model, a regression models, decision trees, a random forest classifier, logistic regression, support vector machine algorithms (SVM), a Naive Bayes classifier, a k-nearest neighbors (K-NN) algorithm, clustering, k-means clustering, a dimensionality reduction algorithm, a gradient boosting algorithm, a probabilistic classifier, and any combinations thereof. 
     
     
         15 . The method of  claim 1 , wherein the depth of penetration model has the form:
   DOP= f ( x, a, t )   where DOP is the depth of penetration as a function of at least x, a, and t, where x is a variable or a vector comprising one or more concentrations or amounts of a cement component in the cement, a is a variable or a vector comprising one or more determinable constants, and t is an exposure time.   
     
     
         16 . The method of  claim 1 , wherein the depth of penetration model has the form: 
       
         
           
             
               DOP 
               = 
               
                 
                   [ 
                   
                     
                       a 
                       0 
                     
                     + 
                     
                       ( 
                       
                         
                           a 
                           1 
                         
                         * 
                         
                           VF 
                           water 
                         
                       
                       ) 
                     
                     + 
                     
                       ( 
                       
                         
                           a 
                           2 
                         
                         * 
                         
                           ( 
                           
                             
                               
                                 C 
                                 2 
                               
                               ⁢ 
                               S 
                             
                             + 
                             
                               
                                 C 
                                 3 
                               
                               ⁢ 
                               S 
                             
                           
                           ) 
                         
                       
                       ) 
                     
                     + 
                     
                       ( 
                       
                         
                           a 
                           3 
                         
                         * 
                         FQ 
                       
                       ) 
                     
                     + 
                     
                       ( 
                       
                         
                           a 
                           4 
                         
                         * 
                         PSD 
                       
                       ) 
                     
                     + 
                     
                       ( 
                       
                         
                           a 
                           5 
                         
                         * 
                         Latex 
                       
                       ) 
                     
                   
                   ] 
                 
                 * 
                 
                   time 
                   
                     
                       a 
                         
                     
                     6 
                   
                 
                 * 
                 
                   e 
                   
                     E 
                     * 
                     
                       1 
                       T 
                     
                   
                 
                 * 
                 
                   ( 
                   
                     
                       a 
                       7 
                     
                     * 
                     P 
                   
                   ) 
                 
               
             
           
         
         where DOP is the depth of penetration, VF water  is a volume fraction of water, C 2 S and C 3 S are mass averaged amounts of dicalcium silicate and tricalcium silicate in the cement respectively, FQ is a foam quality factor, PSD is a particle size distribution factor, Latex is a mass percent of an active amount of fluid loss polymer in the cement, time is the exposure time, E is an activation energy, T is a temperature, P is a pressure, and a0, a1, a2, a3, a4, a5, a6, and a7 are one or more determinable constants. 
       
     
     
         17 . The method of  claim 1 , wherein the cement property model has the form:
   CP= f (VF modified , CP control , CP modified )   where CP is a material property of a chemically modified cement, VF modified  is a volume fraction of a chemically modified portion in a chemically modified cement, CP control  is a material property of a chemically unmodified portion of a cement, and CP modified  is a material property of a modified portion of a chemically modified cement.   
     
     
         18 . The method of  claim 17 , wherein the predicting of the material property involves use of a function having the form: 
       
         
           
             
               
                 
                   CP 
                   modified 
                 
                 
                   CP 
                   control 
                 
               
               = 
               
                 f 
                 ⁡ 
                 ( 
                 
                   Design 
                   , 
                      
                   Duration 
                   , 
                     
                   Environment 
                 
                 ) 
               
             
           
         
         where Design is a variable or vector representing one or more wellbore design factors, Duration is an exposure time, and Environment is a variable or vector representing one or more environmental factors. 
       
     
     
         19 . A method of evaluating a wellbore comprising:
 preparing a plurality of cement slurries, wherein the plurality of cement slurries each comprise a cement and volume fraction of water;   curing the plurality of cement slurries to form a plurality of set cement samples;   exposing the plurality of set cement samples to an invasive fluid;   allowing the invasive fluid to at least partially modify the plurality of set cement samples to form a plurality of chemically modified cement samples;   measuring a cement property of each of the plurality of chemically modified cement samples to generate a cement property dataset;   predicting a cement property of a cement exposed for a period of time to an invasive fluid based at least in part on the cement property dataset; and   inputting the predicted cement property and one or more loads into a numerical simulator for modeling regions at or near the wellbore; and   performing an integrity analysis of the cement based at least in part on an output of the numerical simulator.   
     
     
         20 . The method of  claim 19 , wherein the output of the numerical simulator comprises strain determined at an interface between a carbonated portion and an uncarbonated portion of the cement.