Repositionable Well Plug

Abstract

Systems and methods are provided for moving a well casing plug to desired locations in a well. The well plug system can be located at a desired position, generate a reversible seal at the location, remove the seal, and relocate. Features of the plug system, such as translocating devices, actuating devices, sensors, and casing penetration tools can allow work to be done at various well hole locations, e.g., without requiring continuous physical connections or communications with the surface. The methods include sealing the well casing plug in a casing, opening ports through the casing, facilitating passage of fluids at hydraulic fracturing pressures to formations outside the casing, reversing the seal, and translocation of the plug system to a new location.

What is claimed is: 
     
         1 . A self-retracting well casing plug system, the system comprising:
 a plug body comprising a proximal end and a distal end;   an expandable seal mounted to the body and adapted to expand and reversibly seal the body in a well casing;   one or more casing grips mounted to the body and adapted to extend from the body and engage the well casing, thereby fixing the plug at a location in the well casing.   
     
     
         2 . The system of  claim 1 , wherein the seal is resilient and comprises a fluid inlet to receive a fluid under pressure, which pressurized fluid expands the seal to contact the well case forming a hydraulic seal; or wherein the seal expands to contact the well casing on urging of an expansion device. 
     
     
         3 . The system of  claim 1 , wherein the one or more casing grips comprise grip teeth directed away from a body axis, whereby the grip teeth are adapted to grip the well casing when the grips are forced out radially from the body. 
     
     
         4 . The system of  claim 3 , wherein the grips are forced out radially by a cam and roller system in the body. 
     
     
         5 . The system of  claim 1 , wherein the well casing or a coupling between well casing segments comprise an internal ridge, and wherein the one or more grips extend to contact the ridge, thereby preventing the plug from moving past the ridge. 
     
     
         6 . The system of  claim 1 , wherein the system comprises an oil or gas well casing. 
     
     
         7 . The system of  claim 1 , further comprising a means of perforating the well casing. 
     
     
         8 . The system of  claim 1 , further comprising a well casing comprising one or more hydraulic fracturing ports and a port slide movable to alternately open or close the one or more hydraulic fracturing ports. 
     
     
         9 . The system of  claim 1 , further comprising one or more distal grips distal to the first proximal grips. 
     
     
         10 . The system of  claim 9 , further comprising one or more extension cylinders between the proximal and distal grips, whereby the distance between the proximal grips and distal grips can be increased or decreased. 
     
     
         11 . The system of  claim 10 , wherein the system is configured to reposition within the well casting by first gripping with a proximal or distal grip, increasing the distance between the proximal and distal grips, releasing the first gripping proximal or distal grip, second gripping with a grip not used in the first gripping, and reducing or increasing the distance between the proximal and distal grips by increasing or decreasing a length of the one or more extension cylinders. 
     
     
         12 . The system of  claim 1 , wherein the plug system is down hole in a well casing and untethered to the surface. 
     
     
         13 . The system of  claim 1 , further comprising a controller and one or more motors configured to actuate features selected from the group consisting of: a proximal grip, a distal grip, an expandable seal, and an extension cylinder. 
     
     
         14 . The system of  claim 13 , wherein the controller is preprogrammed or is adapted to receive communications from the surface while the plug system is down hole. 
     
     
         15 . The system of  claim 13 , wherein the controller is in communication to receive inputs from one or more sensors mounted in the plug body. 
     
     
         16 . The system of  claim 1 , further comprising a deployment and retrieval tool adapted to contact and capture the plug body. 
     
     
         17 . A plug system for a well casing, the plug system comprising:
 a plug body;   an expandable seal mounted to the body and adapted to expand and reversibly seal the body in a well casing;   one or more casing grips mounted to the body and extendable out from the body to engage the well casing;   a source of power to extend said casing grips, whereby the plug system is movable along the well casing.   
     
     
         18 . The system of  claim 17 , wherein the seal is resilient and expands to contact the well casing on urging of a mechanical expansion device. 
     
     
         20 . The system of  claim 17 , wherein the source of power is a motor in the plug body. 
     
     
         22 . The system of  claim 17 , further comprising one or more casing grips mounted to the body and adapted to extend out from the body and engage the well casing, thereby fixing the plug at a location in the well casing. 
     
     
         23 . A method of plugging a well casing, the method comprising:
 providing a well casing plug comprising:   a plug body comprising a proximal end and a distal end;   an expandable seal mounted to the plug body and adapted to expand and reversibly seal the body in the well casing;   a) propelling the plug body along an inside of the well casing to a first location, wherein a gripping element in contact with the well casing provides a force propelling the plug body;   b) sealing the expandable seal against the well casing;   c) unsealing the seal from the well casing; and   d) propelling the plug to a different location within the well casing.   
     
     
         24 . The method of  claim 23 , wherein the propelling is provided by a drive wheel or by a grip/expansion cylinder combination. 
     
     
         25 . The method of  claim 23 , further comprising opening a port or perforation through the well casing between propelling steps. 
     
     
         26 . The method of  claim 25 , wherein opening a port of perforation comprises opening a port prepositioned in the well casing or opening a perforation comprises use of a pyrotechnic. 
     
     
         27 . The method of  claim 26 , further comprising pressurizing the inside of the well casing to expose an environment outside the outside of the well casing to hydraulic fracturing pressures. 
     
     
         28 . The method of  claim 23 , further comprising repeating steps b) to d). 
     
     
         29 . A well casing plug system comprising:
 a plug body;   an expandable seal mounted to the body and adapted to expand and reversibly seal the body in a well casing;   a digital controller in the plug body;   and one or more motors configured to energize movement of well plug actuators;   wherein the controller is configured to receive input from sensors or control the one or more motors.   
     
     
         30 . The well plug system of  claim 29 , wherein the seal is resilient and comprises a fluid inlet to receive a fluid under pressure, or wherein the seal is resilient and expands to contact the well casing on urging of a mechanical expansion device or annular wedge. 
     
     
         31 . The well plug system of  claim 29 , wherein the actuators are selected from the group consisting of: a proximal grip, a distal grip, the expandable seal, and an extension cylinder. 
     
     
         32 . The well plug system of  claim 29 , wherein the sensors are mounted to the plug body. 
     
     
         33 . The well plug system of  claim 29 , wherein the controller is preprogrammed or is adapted to receive communications from the surface while the well plug is down hole. 
     
     
         34 . The well plug system of  claim 29 , further comprising a deployment and retrieval tool adapted to contact and capture the plug body. 
     
     
         35 . The well plug system of  claim 29 , further comprising one or more drive wheels mounted to the body and extendable out from the body to engage the well casing and propel the body along the well casing. 
     
     
         36 . The well plug system of  claim 29 , further comprising one or more first casing grips mounted to the body and adapted to extend out from the body and engage the well casing, thereby fixing the plug at a location in the well casing. 
     
     
         37 . The well plug system of  claim 36 , further comprising one or more distal grips distal to the first proximal grips, and further comprising one or more extension cylinders between the proximal and distal grips, whereby the distance between the proximal grips and distal grips can be increased or decreased. 
     
     
         38 . The well plug system of  claim 29 , comprising the plug body and one or more perforator guns.