Testing methodology and workflow to quantify drilling fluids influences on formation mechanical properties

Abstract

Systems and methods for quantifying drilling fluid influence on formation mechanical properties are disclosed. The methods include obtaining drilling mud formulations and properties; determining a subset of the drilling mud formulations; obtaining core plugs from a subsurface; measuring first rock mechanical properties from the core plugs for each of the subset of the drilling mud formulations; performing a fluid invasion of the core plugs with drilling muds; measuring second rock mechanical properties of the core plugs after the fluid invasion; modeling an effect of the drilling muds on a formation breakdown; determining a mud weight range for each of the subset of the drilling mud formulations; and selecting a preferred drilling mud formulation for a drilling operation based on the mud weight range for the subset of the drilling mud formulations.

What is claimed is: 
     
         1 . A method, comprising:
 obtaining drilling mud formulations of historical fracking jobs;   obtaining drilling mud properties from the drilling mud formulations;   determining a subset of the drilling mud formulations based on the drilling mud properties of the historical fracking jobs that were successful;   obtaining core plugs from a subsurface;   measuring first rock mechanical properties from the core plugs for each of the subset of the drilling mud formulations;   performing a fluid invasion of the core plugs with drilling muds created with each of the subset of the drilling mud formulations;   measuring second rock mechanical properties of the core plugs for each of the subset of the drilling mud formulations after the fluid invasion;   modeling an effect of the drilling muds on a formation breakdown using the drilling mud properties of the subset of the drilling mud formulations, the first rock mechanical properties, and the second rock mechanical properties;   determining a mud weight range for each of the subset of the drilling mud formulations based on the effect of the drilling muds on the formation breakdown; and   selecting a preferred drilling mud formulation for a drilling operation based on the mud weight range for the subset of the drilling mud formulations.   
     
     
         2 . The method of  claim 1 , wherein the first rock mechanical properties and the second rock mechanical properties are measured by one or more of: a tri-axial test at unconfined conditions, a tri-axial test at confined conditions, and a Brazilian testing apparatus. 
     
     
         3 . The method of  claim 1 , wherein a geomechanical model determines the mud weight range for each of the subset of the drilling mud formulations. 
     
     
         4 . The method of  claim 3 , wherein the geomechanical model is a finite element model. 
     
     
         5 . The method of  claim 1 , wherein a cause of the formation breakdown is determined by a scanning electron microscope. 
     
     
         6 . The method of  claim 1 , wherein the drilling operation is a hydraulic fracturing operation. 
     
     
         7 . The method of  claim 6 , wherein an upper bound of the mud weight range determines when the hydraulic fracturing operation is feasible. 
     
     
         8 . The method of  claim 1 , wherein the mud weight range indicates when a borehole is stable for drilling operations. 
     
     
         9 . A non-transitory computer-readable memory comprising computer-executable instructions stored thereon that, when executed on a processor, cause the processor to perform the steps of:
 determining a subset of drilling mud formulations based on drilling mud properties of historical fracking jobs that were successful;   measuring first rock mechanical properties from core plugs for each of the subset of drilling mud formulations;   measuring second rock mechanical properties of the core plugs for each of the subset of drilling mud formulations after a fluid invasion of the core plugs with drilling muds created with each of the subset of drilling mud formulations;   modeling an effect of the drilling muds on a formation breakdown using the drilling mud properties of the subset of drilling mud formulations, the first rock mechanical properties, and the second rock mechanical properties;   determining a mud weight range for each of the subset of drilling mud formulations based on the effect of the drilling muds on the formation breakdown; and   selecting a preferred drilling mud formulation for a drilling operation based on the mud weight range for the subset of drilling mud formulations.   
     
     
         10 . The non-transitory computer-readable memory of  claim 9 , wherein the first rock mechanical properties and the second rock mechanical properties are measured by one or more from the following list: a tri-axial test at unconfined conditions, a tri-axial test at confined conditions, and a Brazilian testing apparatus. 
     
     
         11 . The non-transitory computer-readable memory of  claim 9 , wherein a geomechanical model determines the mud weight range for each of the subset of drilling mud formulations. 
     
     
         12 . The non-transitory computer-readable memory of  claim 11 , wherein the geomechanical model is a finite element model. 
     
     
         13 . The non-transitory computer-readable memory of  claim 9 , wherein a cause of the formation breakdown is determined by a scanning electron microscope. 
     
     
         14 . The non-transitory computer-readable memory of  claim 9 , wherein the drilling operation is a hydraulic fracturing operation. 
     
     
         15 . The non-transitory computer-readable memory of  claim 14 , wherein an upper bound of the mud weight range determines when the hydraulic fracturing operation is feasible. 
     
     
         16 . The non-transitory computer-readable memory of  claim 9 , wherein the mud weight range indicates when a borehole is stable for drilling applications. 
     
     
         17 . A system, comprising:
 a computer processor, configured to:
 determine a subset of drilling mud formulations based on drilling mud properties of historical fracking jobs that were successful, 
 measure first rock mechanical properties from core plugs for each of the subset of drilling mud formulations, 
 measure second rock mechanical properties of the core plugs for each of the subset of drilling mud formulations after a fluid invasion of the core plugs with drilling muds created with each of the subset of drilling mud formulations, 
 model an effect of the subset of drilling mud formulations on a formation breakdown using the drilling mud properties, the first rock mechanical properties, and the second rock mechanical properties, 
 determine a mud weight range for each of the subset of drilling mud formulations based on the effect of the subset of drilling mud formulations on the formation breakdown; and 
 select a preferred drilling mud formulation for a drilling operation based on the mud weight range for the subset of drilling mud formulations; and 
   a laboratory, configured to:
 receive the core plugs from a subsurface, 
 determine the drilling mud properties from the subset of drilling mud formulations, 
 measure the first rock mechanical properties from the core plugs for each of the subset of drilling mud formulations, 
 measure the second rock mechanical properties from the core plugs for each of the subset of drilling mud formulations, and 
 perform the fluid invasion of the core plugs with the drilling muds created with each of the subset of drilling mud formulations. 
   
     
     
         18 . The system of  claim 17 , further comprising a scanning electron microscope configured to determine a cause of the formation breakdown. 
     
     
         19 . The system of  claim 17 , further comprising a geomechanical model configured to determine the mud weight range for each of the subset of drilling mud formulations. 
     
     
         20 . The system of  claim 19 , wherein the geomechanical model is a finite element model.