Methods of determining borehole characteristics

Abstract

A method of determining borehole characteristics comprises arranging at least one sensing fiber along a borehole, causing pressure changes in the borehole, and measuring strain along the sensing fiber to obtain strain data. The strain data obtained thereby can be interpreted, for example, to determine borehole fracture geometry and to determine borehole perforation cluster efficiency. These results can be used to improve well completion and stimulation designs, increase field production, and/or decrease costs.

What is claimed is: 
     
         1 . A method of determining borehole characteristics comprising:
 arranging at least one sensing fiber along a borehole;   causing pressure changes in the borehole; and   measuring strain along the at least one sensing fiber to obtain strain data.   
     
     
         2 . The method of  claim 1 , wherein the borehole along which the at least one sensing fiber is arranged has been fractured. 
     
     
         3 . The method of  claim 2 , further comprising:
 determining borehole fracture geometry based on the strain data.   
     
     
         4 . The method of  claim 2 , wherein the borehole along which the at least one sensing fiber is arranged has been hydraulically fractured. 
     
     
         5 . The method of  claim 2 , wherein the borehole along which the at least one sensing fiber is arranged has been naturally fractured. 
     
     
         6 . The method of  claim 1 , wherein the borehole along which the at least one sensing fiber is arranged is a borehole of a vertical producer well or of a vertical injector well. 
     
     
         7 . The method of  claim 1 , wherein the borehole along which the at least one sensing fiber is arranged is a borehole of a conventional well. 
     
     
         8 . The method of  claim 1 , further comprising:
 determining borehole perforation cluster efficiency based on the strain data.   
     
     
         9 . The method of  claim 1 , wherein the at least one sensing fiber includes at least one optic fiber. 
     
     
         10 . The method of  claim 1 , wherein the causing of the pressure changes in the borehole includes at least one selected from the group consisting of: shutting-in the borehole, changing a choke size of the borehole, or performing an injection in the borehole. 
     
     
         11 . The method of  claim 1 , wherein the measuring of strain along the at least one sensing fiber is performed before the pressure changes to obtain a baseline strain reading, during pressure changes to obtain time-dependent strain variation data, and after the pressure changes to obtain strain recovery data, wherein the strain data includes the baseline strain reading, the time-dependent strain variation data, and the strain recovery data. 
     
     
         12 . The method of  claim 1 , wherein the measuring of strain along the at least one sensing fiber includes performing distributed strain sensing. 
     
     
         13 . The method of  claim 1 , further comprising:
 measuring temperature along the at least one sensing fiber to obtain temperature data.   
     
     
         14 . The method of  claim 1 , further comprising:
 obtaining pressure data from the borehole; and   comparing the pressure data to the strain data to obtain cluster performance data.   
     
     
         15 . The method of  claim 1 , wherein the borehole is a borehole of a well undergoing production, and the method further comprises:
 ceasing production from the well prior to the causing of the pressure changes in the borehole; and   resuming production from the well after the causing of the pressure changes in the borehole.