Drilling parameter recommendations based on offset well data

Abstract

A system and method of steering a drill string when forming a wellbore in a subterranean formation. The method includes identifying two or more parameters associated with steering the drill string in a subject well; determining, via a statistical model, individual contributions to a tool yield model by each of the identified parameters; and suggesting, based on the statistical model and on current values of the identified parameters, one or more changes in the identified parameters, the changes sufficient to alter a trajectory of the drill string in the subject well.

What is claimed is: 
     
         1 . A method of steering a drill string when forming a wellbore in a subterranean formation, the method comprising:
 identifying two or more parameters associated with steering the drill string in a subject well;   determining, via a statistical model, individual contributions to a tool yield model by each of the identified parameters; and   suggesting, based on the statistical model and on current values of the identified parameters, one or more changes in the identified parameters, the changes sufficient to alter a trajectory of the drill string in the subject well.   
     
     
         2 . The method of  claim 1 , wherein determining individual contributions includes:
 obtaining the tool yield model, wherein the tool yield model is a regression model of drilling information from similar wells;   performing statistical modeling of the tool yield model to identify independent contributions to output as a linear combination of the independent contributions to output of each identified parameter; and   performing regression analysis of each parameter/output pair.   
     
     
         3 . The method of  claim 1 , wherein the tool yield model is a regression model of drilling information for curved sections of boreholes of similar wells, the regression model including hyperparameter tuning. 
     
     
         4 . The method of  claim 1 , wherein determining individual contributions to a tool yield model by each of the identified parameters includes retrieving drilling information obtained from offset wells. 
     
     
         5 . The method of  claim 4 , wherein retrieving drilling information obtained from offset wells includes identifying, as offset wells, wells with characteristics like the subject well that are within a radius, R, of the subject well. 
     
     
         6 . The method of  claim 5 , wherein identifying wells with characteristics like the subject well includes calculating a similarity score for each well and, if the similarity score is less than a threshold value, identifying the well as an offset well. 
     
     
         7 . The method of  claim 5 , wherein identifying wells with characteristics like the subject well includes:
 querying a database to obtain drilling information associated with different wells; and   filtering the drilling information to identify wells that used a similar bit type, size, and design as the subject well.   
     
     
         8 . The method of  claim 5 , wherein identifying wells with characteristics like the subject well includes:
 querying a database to obtain drilling information associated with different wells; and   filtering the drilling information to identify wells that used a similar tool size, type, and design as the subject well.   
     
     
         9 . The method of  claim 5 , wherein identifying wells with characteristics like the subject well includes:
 querying a database to obtain drilling information associated with different wells; and   filtering the drilling information to identify wells that used a similar borehole apparatus (BHA) as the subject well.   
     
     
         10 . The method of  claim 1 , wherein the tool yield model is a regression model of drilling information of similar wells and wherein identifying wells like the subject well includes:
 querying a database to obtain the drilling information associated with different wells;   filtering the drilling information to identify wells that are within a radius R of the subject well and that used:
 a similar bit type, size, and design as the subject well; 
 a similar tool size, type, and design as the subject well; and 
 a similar borehole apparatus (BHA) as the subject well; 
   calculating a similarity score for each identified well; and   if the similarity score is less than a threshold value, labeling the well as an offset well.   
     
     
         11 . The method of  claim 10 , wherein the method further comprises:
 applying a regression model to the drilling information of sections of the offset well that curve to determine the tool yield model.   
     
     
         12 . The method of  claim 1 , wherein suggesting a change in one of the identified parameters includes:
 calculating a dogleg severity (DLS) required to meet a well plan for the subject well;   calculating a current DLS; and   if the current DLS is less than the required DLS, applying current parameter values, limits and the statistical model to calculate a direction and amount by with the parameters need to change to obtain the required DLS.   
     
     
         13 . The method of  claim 1 , wherein suggesting one or more changes in the identified parameters includes:
 calculating a dogleg severity (DLS) required to meet a well plan for the subject well;   calculating a current DLS; and   if the current DLS is less than the required DLS, determining changes in the parameters that maximize rate of penetration (ROP) or achieves a ROP within certain constrained limits at the required DLS.   
     
     
         14 . The method of  claim 13 , wherein determining changes in the parameters that maximize rate of penetration (ROP) at the required DLS includes solving an optimization problem using an ROP model and the tool yield model. 
     
     
         15 . The method of  claim 1 , wherein the method further comprises:
 incorporating the suggested changes in the identified parameters in the drilling system of the subject well;   receiving feedback from the drilling system after incorporating the suggested changes, wherein the feedback includes new values for one or more of the identified parameters;   updating the current values to reflect the new values; and   suggesting, based on the statistical model and on the updated current values of the identified parameters, one or more changes in the identified parameters.   
     
     
         16 . A nonvolatile computer readable medium having instructions that, when executed by a processor:
 identify two or more parameters associated with steering a drill string in a subject well;   determine, via a statistical model, individual contributions to a tool yield model by each of the identified parameters; and   suggest, based on the statistical model and on current values of the identified parameters, one or more changes in the identified parameters, the changes sufficient to alter a trajectory of the drill string in the subject well.   
     
     
         17 . The computer readable medium of  claim 16 , wherein the instructions that, when executed by the processor, suggest one or more changes in the identified parameters include instructions that, when executed by the processor:
 calculate a dogleg severity (DLS) required to meet a well plan for the subject well;   determine a current DLS; and   if the current DLS is less than the required DLS, determine changes in the identified parameters needed to obtain the required DLS.   
     
     
         18 . A method of determining tool yield as a function of dogleg severity (DLS) for a drill string in a subject well, the method comprising:
 querying a database to obtain drilling information associated with different wells;   filtering the drilling information to identify wells from the database that are similar to the subject well and that are within a radius R of the subject well;   calculating a similarity score for each identified well;   if the similarity score is less than a threshold value, labeling the well as an offset well; and   applying a regression model with hyperparameter tuning to the drilling information of sections of the offset well that curve.   
     
     
         19 . The method of  claim 18 , wherein filtering the drilling information to identify wells from the database that are like the subject well includes filtering the identified wells to find wells that have one or more of:
 a similar bit type, size, and design as the subject well;   a similar tool size, type, and design as the subject well;   a similar borehole apparatus (BHA) as the subject well;   a similar rotary steering system (RSS) as the subject well;   a similar inclination as the planned inclination with respect to measured depth of the drill string; and   a similar true vertical depth (TVD) as the planned TVD with respect to measured depth of the subject well.   
     
     
         20 . The method of  claim 18 . wherein the regression model includes hyperparameter tuning.