Method for controlling the trajectory of a hydraulic fracture in strata-containing natural fractures

Abstract

The method of controlling the parameters of a hydraulic fracture comprises creating a matrix of relationship between initial formation, injection and fracture parameters of and a predicted increment of a hydraulic fracture path. The matrix is used for retrieving and deriving the predicted increment of the fracture path, depending on the actual initial parameters of a fracture being created. The actual increment of the hydraulic fracture path is measured and compared with the predicted increment of the fracture path. In case of a discrepancy between the actual and predicted increments, the actual initial parameters of the fracture are changed.

1 . Method for controlling a hydraulic fracture path in formations containing natural fractures comprising:
 a) creating a matrix of relationship between initial formation, injection and fracture parameters and a predicted increment of a hydraulic fracture path,   b) starting a hydraulic fracturing process,   c) measuring actual initial parameters of a hydraulic fracture being created,   d) using the matrix for retrieving and deriving the predicted increment of the fracture path, depending on the actual initial parameters of the fracture being created,   e) measuring an actual increment of a path of the hydraulic fracture being created ,   f) comparing the actual increment of the path of the fracture being created with the predicted increment of the fracture path, and   g) in case of a discrepancy between the actual and the predicted increments changing the actual initial parameters of the fracture being created.   
     
     
         2 . Method of  claim 1 , wherein the matrix of relationship between initial formation, injection and fracture parameters and the predicted increment of the hydraulic fracture path is created through numerical calculations or experiments or both. 
     
     
         3 . Method of  claim 1 , wherein the initial formation, injection and fracture parameters include formation and natural fracture parameters, fracturing fluid injection parameters and initial fracture path parameters. 
     
     
         4 . Method of  claim 3 , wherein formation mechanical stresses are used as the formation and natural fracture parameters. 
     
     
         5 . Method of  claim 3 , wherein coefficients of interface adhesion are used as the formation and natural fracture parameters. 
     
     
         6 . Method of  claim 3 , wherein coefficients of interface friction are used as the formation and natural fracture parameters. 
     
     
         7 . Method of  claim 3 , wherein a relative angle between the hydraulic fracture and a natural fracture in a point of their contact is used as the formation and natural fracture parameters. 
     
     
         8 . Method of  claim 3 , wherein a parameter characterizing the location of natural fractures is used as the formation and natural fracture parameters. 
     
     
         9 . Method of  claim 3 , wherein a natural fracture size parameter is used as the formation and natural fracture parameters. 
     
     
         10 . Method of  claim 3 , wherein a viscosity of a fracturing fluid to be injected is used as the fracturing fluid injection parameter. 
     
     
         11 . Method of  claim 3 , wherein a fracturing fluid injection rate is used as the fracturing fluid injection parameter. 
     
     
         12 . Method of  claim 3 , wherein an average fracturing fluid pressure in the hydraulic fracture is used as the fracturing fluid injection parameter. 
     
     
         13 . Method of  claim 3 , wherein a fracture length is used as the initial fracture path parameter. 
     
     
         14 . Method of  claim 3 , wherein a gap between a hydraulic fracture tip and an interface is used as the initial fracture path parameter. 
     
     
         15 . Method of  claim 1 , wherein the initial formation, injection and fracture parameters and the predicted increment of the hydraulic fracture path are represented in the matrix as normalized values. 
     
     
         16 . Method of  claim 1 , wherein operations c), d), e), f), g) are performed in the real-time mode of the hydraulic fracturing process. 
     
     
         17 . Method of  claim 1 , wherein operations c), d), e), f), g) are performed by using a control device. 
     
     
         18 . Method of  claim 17 , wherein the control device is capable of converting the actually measured values into normalized values, and vice versa. 
     
     
         19 . Method of  claim 1 , wherein the actual initial parameters of the hydraulic fracture being created are measured by using measuring techniques. 
     
     
         20 . Method of  claim 1 , wherein the actual increment of the hydraulic fracture being created is measured by using measuring techniques.