Event prediction using state-space mapping during drilling operations

A system comprising:

• at least one processor;
• and
• a memory coupled to the processor and having processor-executable instructions stored therein, which, when executed by the processor, cause the processor to perform a plurality of functions, including functions to:
• retrieve, from a database over a communication network, regression data associated with coefficients of a predictive model for a downhole event during a drilling operation along a planned path of a wellbore within a subsurface formation, the regression data including a record of changes in historical coefficient values associated with prior occurrences of the downhole event;
• estimate a value of an operating variable as the wellbore is drilled over different stages of the drilling operation along the planned path, based on values of the coefficients of the predictive model and real-time data acquired during each stage of the drilling operation, wherein the values of the coefficients are adjusted between successive stages of the drilling operation when a difference between the estimated value and an actual value of the operating variable derived from the real-time data exceeds an error tolerance;
• track a percentage change in the values of the coefficients as adjusted between successive stages of the drilling operation along the planned path of the wellbore;
• identify a correlation between the percentage change in the values tracked for at least one of the coefficients and a corresponding change in the historical coefficient values associated with the prior occurrences of the downhole event;
• estimate an occurrence of the downhole event along the planned path of the wellbore, based on the identified correlation;
• adjust the planned path of the wellbore, based on the estimated occurrence of the downhole event;
• and
• control drilling of the wellbore according to the adjusted planned path.

A computer-readable storage medium having instructions stored therein, which when executed by a computer cause the computer to perform a plurality of functions, including functions to:

• retrieve, from a database over a communication network, regression data associated with coefficients of a predictive model for a downhole event during a drilling operation along a planned path of a wellbore within a subsurface formation, the regression data including a record of changes in historical coefficient values associated with prior occurrences of the downhole event;
• estimate a value of an operating variable as the wellbore is drilled over different stages of the drilling operation along the planned path, based on values of the coefficients of the predictive model and real-time data acquired during each stage of the drilling operation, wherein the values of the coefficients are adjusted between successive stages of the drilling operation when a difference between the estimated value and an actual value of the operating variable derived from the real-time data exceeds an error tolerance;
• track a percentage change in the values of the coefficients as adjusted between successive stages of the drilling operation along the planned path of the wellbore;
• identify a correlation between the percentage change in the values tracked for at least one of the coefficients and a corresponding change in the historical coefficient values associated with the prior occurrences of the downhole event;
• estimate an occurrence of the downhole event along the planned path of the wellbore, based on the identified correlation;
• adjust the planned path of the wellbore, based on the estimated occurrence of the downhole event;
• and
• control drilling of the wellbore according to the adjusted planned path.