Resuming interrupted communication through a wellbore

Abstract

Resuming communication along a wellbore after a drilling stand or other occurrence that reduces the flow rate of the drilling fluid into a borehole being drilled in a drilling procedure or causes perturbations in the pressure of the drilling fluid in the borehole by measuring a first flow rate of drilling fluid being pumped into the drillstring during the drilling procedure before adding a section of drill pipe to the drillstring or before the pressure perturbation and increasing the flow rate of the drilling fluid being pumped into the drillstring above the first flow rate after the section of drill pipe has been added to the drillstring or the pressure perturbation has occurred.

1 . A method for controlling drilling fluids in a drilling procedure to drill a borehole from a surface location through an earth formation to reduce interrupted communication through the borehole, comprising:
 receiving a range of desired optimal flow rates for pumping the drilling fluids into a drillstring, wherein the drillstring extends from the surface location down the borehole and the optimal flow rates are determined so as to keep a bottomhole pressure of the drilling fluid in the borehole within an optimal operating pressure window having upper and lower pressure bounds;   pumping the drilling fluids into the drillstring at a first optimal flow rate configured to maintain the pressure within the optimal operating pressure window;   reducing the flow rate of the drilling fluid below the first optimal flow rate;   increasing the flow rate of the drilling fluid to a value above said first optimal flow rate; and   reducing the flow rate of the drilling fluid from the increased flow rate to a second optimal flow rate, wherein the second flow rate is within the desired optimal flow rates and may be the same or different to the first optimal flow rate, and wherein reduction of the flow rate of the drilling fluid from the increased flow rate to the second optimal flow rate occurs over a period of time.   
     
     
         2 . The method of  claim 1 , wherein the reduction in flow rate to a rate below said first optimal flow rate is performed to provide for connecting a drill pipe stand to the drillstring. 
     
     
         3 . The method of  claim 1 , wherein the increased flow rate and/or the period of time are processed to provide that pressure in the borehole is kept within the optimal operating pressure window. 
     
     
         4 . The method of  claim 1 , wherein the increased flow rate is up to 30% greater than the first optimal flow rate, up to 20% greater than the first optimal flow rate and/or up to 10% greater than the first optimal flow rate. 
     
     
         5 . The method of  claim 1  wherein the period of time is less than 5 minutes or less than 2 minutes or less than 1 minute. 
     
     
         6 . The method of  claim 1 , further comprising
 performing mud pulse telemetry after the second optimal flow rate is achieved.   
     
     
         7 . The method according to  claim 1 , wherein the steps of the method of  claim 1  are repeated at a later point in time and data from the earlier steps are used to improve the effectiveness of the method carried out at the later point in time. 
     
     
         8 . A system for controlling flow rates of drilling fluids being pumped into a drillstring during a drilling procedure to drill a borehole from a surface location through an earth formation to resume communication through the drilling fluids after an interruption, the system comprising:
 a stored range of desired optimal flow rates for pumping the drilling fluids into the drillstring, wherein the optimal flow rates are determined so as to keep a bottomhole pressure in the borehole within an optimal operating pressure window having upper and lower pressure levels, wherein the upper pressure level comprises a pressure below a fracture pressure of the formation being drilled and the lower pressure level comprises a pressure above a pore pressure of the formation   one or more pumps configured to pump drilling fluid into the drillstring; and   a processor configured to control the one or more pumps, wherein the processor controls the pumps:
 to pump the drilling fluid at a first optimum flow rate, wherein the optimum flow rate is within the range of desired optimal flow rates; 
 after a reduction in the rate at which the drilling fluid is pumped falls below the optimum flow rate, to pump the drilling fluid into the drillstring at an increased flow rate that is greater than the optimal flow rate; and 
 to reduce the flow rate from the increased flow rate to a second optimal flow rate, wherein the second optimal flow rate is within the range of desired optimal flow rates and may be the same or different to the first optimal flow rate. 
   
     
     
         9 . The system of  claim 8 , further comprising:
 a pressure sensor in communication with the processor configured to measure a pressure in the drillstring.   
     
     
         10 . The system of  claim 8 , further comprising:
 a choke configured to control the pressure in the drillstring.   
     
     
         11 . The system of  claim 8 , further comprising:
 a mud pulse telemetry system.   
     
     
         12 . The system of  claim 8 , further comprising:
 a sensor for determining when a connection has been made in the drillstring.   
     
     
         13 . The system of  claim 8 , further comprising a display configured to display at least one of a flow rate of the drilling fluid into the drillstring, a pressure in the drillstring at the surface, a pressure in the drillstring at a lower end of the borehole and the pressure window. 
     
     
         14 . A method for controlling drilling fluids in a drilling procedure to drill a borehole from a surface location through an earth formation to reduce interrupted communication through the borehole, comprising:
 measuring a first flow rate of drilling fluid pumped into a drillstring during the drilling procedure before adding a section of drill pipe to the drillstring; and   increasing flow rate of the drilling fluid pumped into the drillstring above the first flow rate immediately after the section of drill pipe has been added to the drillstring.   
     
     
         15 . The method of  claim 14 , further comprising:
 sending a mud pulse telemetry signal through the drilling fluid in the wellbore.   
     
     
         16 . The method of  claim 14 , further comprising:
 reducing the flow rate of the drilling fluid from the increased flow rate to a reduced flow rate.   
     
     
         17 . The method of  claim 14 , wherein the reduced flow rate comprises a flow rate configured to provide that a downhole pressure of the drilling fluid in the borehole is within an optimal operating pressure window 
     
     
         18 . The method of  claim 17 , wherein the flow rate of the drilling fluid exceeds the reduced flow rate for a period of time. 
     
     
         19 . The method of  claim 18 , wherein the increased flow rate and/or the period of time are determined to provide that the downhole pressure does not exceed the optimal operating pressure window. 
     
     
         20 . The method of  claim 18 , wherein the first flow rate is provided to be a flow rate within a desired range of flow rates, and wherein the desired range of flow rates comprise flow rates that maintain a bottomhole pressure within an operating pressure window having an upper pressure below a fracturing pressure of the earth formation and a lower pressure above a pore pressure of the earth formation. 
     
     
         21 . The method of  claim 20 , wherein the increase flow rate is outside of the desired range of flow rates. 
     
     
         22 . A system for controlling drilling fluids in a drilling procedure to drill a borehole from a surface location through an earth formation to reduce interrupted communication through the borehole, comprising:
 a sensor for measuring a flow rate of drilling fluid pumped into a drillstring during the drillstring procedure; and   a processor in communication with the sensor and configured to control the pump to increase a flow rate of the drilling fluid pumped into the drillstring above a first flow rate immediately after a section of drill pipe has been added to the drillstring, wherein the first flow rate is a flow rate of the drilling fluid pumped into the drillstring before the section of drill pipe has been added to the drillstring.   
     
     
         23 . The system of  claim 24 , wherein the processor controls the pump to reduce the flow rate of the drilling fluid from the increased flow rate to a reduced flow rate. 
     
     
         24 . The method of  claim 25 , wherein the reduced flow rate comprises a flow rate configured to provide that a downhole pressure of the drilling fluid in the borehole is within an optimal operating pressure window 
     
     
         25 . The method of  claim 26 , wherein the flow rate of the drilling fluid exceeds the reduced flow rate for a period of time. 
     
     
         26 . The method of claim  27 , wherein the increased flow rate and/or the period of time are processed by the processor to provide that the downhole pressure does not exceed the optimal operating pressure window.