Fracturing while tripping

Abstract

A drill string includes drill pipe and a modular fracturing sub. A processor can control the drill string to drill a wellbore to some desired depth. The drill string is positioned at a desired location in the wellbore and a section of the wellbore is hydraulically isolated, forming a cavity. Existing fluid may be evacuated from the cavity and fracturing fluid injected into the cavity until a desired level of fracturing is attained. Retrievable packers are used for the hydraulic isolation. A pump evacuates the existing fluid via ports in the fracturing sub. The ports may also be used when injecting fracturing fluid. Seismic sensors may be distributed along the drill string to monitor fracture growth. Logging-while-drilling tools may be integrated into the drill string. Fluid from the lower portion of the wellbore is blocked by a lower sealing unit on a bottomhole assembly.

What is claimed is: 
     
         1 . A method, comprising:
 providing a drill string comprising drill pipe and a fracturing sub;   drilling a wellbore to a desired depth using the drill string;   positioning the drill string at a desired location in the wellbore;   hydraulically isolating a section of the wellbore and forming a cavity between the drill string and the wall of the isolated section of the wellbore using the fracturing sub; and   injecting fluid into the cavity until a desired pressure within the cavity is attained.   
     
     
         2 . The method of  claim 1 , wherein the positioning the drill string comprises placing the fracturing sub adjacent to a zone of interest. 
     
     
         3 . The method of  claim 2 , wherein the positioning the drill string further comprises placing the fracturing sub adjacent to a subsurface station within the zone of interest. 
     
     
         4 . The method of  claim 1 , wherein the hydraulically isolating comprises actuating two or more retrievable packers. 
     
     
         5 . The method of  claim 1 , further comprising pumping fluid out of the isolated section. 
     
     
         6 . The method of  claim 5 , further comprising passing the fluid through one or more ports in the fracturing sub. 
     
     
         7 . The method of  claim 1 , wherein the desired pressure corresponds to a desired level of fracturing. 
     
     
         8 . The method of  claim 1 , further comprising providing one or more seismic sensors and monitoring the fracturing using the one or more seismic sensors. 
     
     
         9 . The method of  claim 8 , wherein the one or more sensors comprises a plurality of sensors distributed along the drill string. 
     
     
         10 . A system, comprising:
 a drill string comprising drill pipe and a fracturing sub; and   a processor located at the earth's surface or carried on the drill string capable of:
 drilling a wellbore to a desired depth using the drill string; 
 positioning the drill string at a desired location in the wellbore; 
 hydraulically isolating a section of the wellbore and forming a cavity between the drill string and the wall of the isolated section of the wellbore using the fracturing sub; and 
 injecting fluid into the cavity until a desired pressure within the cavity is attained. 
   
     
     
         11 . The system of  claim 10 , wherein the fracturing sub comprises two or more retrievable packers. 
     
     
         12 . The system of  claim 10 , wherein the fracturing sub comprises a pump. 
     
     
         13 . The system of  claim 10 , wherein the fracturing sub comprises one or more ports. 
     
     
         14 . The system of  claim 13 , wherein the one or more ports are activated remotely by command or automatically activated. 
     
     
         15 . The system of  claim 10 , wherein the fracturing sub comprises one or more spacers. 
     
     
         16 . The system of  claim 10 , wherein the fracturing sub comprises two or more modules. 
     
     
         17 . The system of  claim 10 , further comprising one or more seismic sensors carried on and distributed along the drill string. 
     
     
         18 . The system of  claim 10 , further comprising logging-while-drilling tools integral with the drill string. 
     
     
         19 . The system of  claim 10 , further comprising a bottomhole assembly having a lower sealing unit. 
     
     
         20 . The system of  claim 19 , wherein the lower sealing unit is selected from the group consisting of a valve and a sealing surface/sealing ball combination.