Systems and Methods for Vertical Depth Control During Extended-Reach Drilling Operations

Abstract

Systems and methods for vertical depth control during extended-reach drilling operations include extending a length of a wellbore to locate a directional drilling assembly at a selected location within an intermediate portion of a subsurface region and detecting a detected pressure at the selected location. The methods further include determining an expected pressure at the selected location, comparing the detected pressure to the expected pressure, and adjusting an orientation of the directional drilling assembly based, at least in part, on the comparison. The expected pressure may be determined based, at least in part, on a reference pressure that was detected previously within the intermediate portion of the subsurface region. The systems include extended-reach drilling operations and/or directional drilling assemblies that include and/or are associated with controllers that are programmed to perform the methods.

1 . A method of controlling a directional drilling assembly that is configured to drill a wellbore within an intermediate portion of a subsurface region, wherein the intermediate portion of the subsurface region extends between a surface region and a reservoir that is present within the subsurface region, the method comprising:
 extending a length of the wellbore to locate the directional drilling assembly at a selected location within the intermediate portion of the subsurface region;   detecting a detected pressure at the selected location;   determining an expected pressure at the selected location, wherein the determining is based, at least in part, on a reference pressure that was previously detected within the intermediate portion of the subsurface region;   comparing the detected pressure to the expected pressure; and   
       adjusting an orientation of the directional drilling assembly based, at least in part, on the comparing. 
     
     
         2 . The method of  claim 1 , wherein the method further includes detecting the reference pressure. 
     
     
         3 . The method of  claim 2 , wherein the wellbore is a second wellbore, and further wherein the detecting the reference pressure includes detecting the reference pressure within a first wellbore that extends within the intermediate portion of the subsurface region, wherein the first wellbore is spaced apart from the second wellbore. 
     
     
         4 . The method of  claim 2 , wherein the detecting the reference pressure includes detecting the reference pressure at a reference location within the intermediate portion of the subsurface region, and further wherein the method includes determining a reference depth of the reference location. 
     
     
         5 . The method of  claim 2 , wherein the detecting the reference pressure includes detecting a plurality of reference pressures at a plurality of reference locations within the intermediate portion of the subsurface region, and further wherein the method includes determining a plurality of reference depths of the plurality of reference locations, wherein each of the plurality of reference pressures is detected at a respective one of the plurality of reference depths. 
     
     
         6 . The method of  claim 2 , wherein the detecting the reference pressure further includes determining a pressure vs. depth profile within the intermediate portion of the subsurface region. 
     
     
         7 . The method of  claim 2 , wherein the method further includes determining a selected depth of the selected location. 
     
     
         8 . The method of  claim 7 , wherein the detecting the reference pressure includes detecting the reference pressure at a reference location within the intermediate portion of the subsurface region that defines a reference depth within the subsurface region, wherein the reference depth is equal to the selected depth, and further wherein the determining the expected pressure includes equating the expected pressure to the reference pressure. 
     
     
         9 . The method of  claim 7 , wherein the detecting the reference pressure includes determining a pressure vs. depth profile within the intermediate portion of the subsurface region, and further wherein the determining the expected pressure includes calculating the expected pressure from the determined pressure vs. depth profile within the intermediate portion of the subsurface region and the determined selected depth of the selected location. 
     
     
         10 . The method of  claim 1 , wherein the comparing includes calculating a difference between a measured pressure and the reference pressure. 
     
     
         11 . The method of  claim 10 , wherein the comparing includes determining that the difference between the reference pressure and the detected pressure is greater than a threshold pressure difference. 
     
     
         12 . The method of  claim 1 , wherein the adjusting includes adjusting a trajectory of the wellbore with the directional drilling assembly. 
     
     
         13 . The method of  claim 1 , wherein the adjusting includes at least one of:
 (i) increasing an angle of inclination of the directional drilling assembly responsive to the detected pressure being greater than the expected pressure; and   (ii) decreasing the angle of inclination of the directional drilling assembly responsive to the detected pressure being less than the expected pressure.   
     
     
         14 . The method of  claim 1 , wherein the adjusting further includes determining an orientation adjustment magnitude. 
     
     
         15 . The method of  claim 14 , wherein the determining the orientation adjustment magnitude includes calculating the orientation adjustment magnitude based, at least in part, on a magnitude of a difference between the reference pressure and the detected pressure. 
     
     
         16 . The method of  claim 14 , wherein the determining the orientation adjustment magnitude includes increasing the orientation adjustment magnitude proportionate to a magnitude of a difference between the reference pressure and the detected pressure. 
     
     
         17 . The method of  claim 14 , wherein the determining the orientation adjustment magnitude includes calculating the orientation adjustment magnitude based, at least in part, on at least one of (i) a density of a fluid within the intermediate portion of the subsurface region, (ii) a density of a fluid within the intermediate portion of the subsurface region that is proximate to the selected location, and (iii) a density of a fluid within the intermediate portion of the subsurface region that is at the selected location. 
     
     
         18 . The method of  claim 1 , wherein the method further includes repeating the extending, the detecting the detected pressure, the determining the expected pressure, the comparing, and the adjusting a plurality of times to extend the wellbore through the intermediate portion and from the surface region to the reservoir. 
     
     
         19 . The method of  claim 1 , wherein the intermediate portion of the subsurface region includes a plurality of intermediate formations, and further wherein the method includes detecting a respective reference pressure in each of the plurality of intermediate formations. 
     
     
         20 . The method of  claim 19 , wherein the method includes repeating the extending, the detecting the detected pressure, the determining the expected pressure, the comparing, and the adjusting in each of the plurality of intermediate formations, and further wherein the determining the expected pressure includes determining the expected pressure in a respective intermediate formation of the plurality of intermediate formations based, at least in part, on the respective reference pressure that was detected within the respective intermediate formation. 
     
     
         21 . The method of  claim 1 , wherein the method further includes extending the wellbore within the reservoir. 
     
     
         22 . The method of  claim 21 , wherein the reservoir defines a gas-filled region, an oil-filled region, and a gas-oil contact region, wherein a lower water-bearing layer is located vertically below the oil-filled region and defines an oil-water contact region, and further wherein, prior to the extending, the method further includes determining a gas-oil contact depth of the gas-oil contact region and determining an oil-water contact depth of the oil-water contact region. 
     
     
         23 . The method of  claim 22 , wherein the wellbore is a second wellbore, wherein the detecting the reference pressure includes detecting the reference pressure within a first wellbore that extends within the gas-filled region, within the oil-filled region, and within the lower water-bearing layer, wherein the first wellbore is spaced apart from the second wellbore, and further wherein the determining the gas-oil contact depth and the determining the oil-water contact depth includes detecting at least one gas pressure within the gas-filled region, detecting at least one oil pressure within the oil-filled region, and detecting at least one water pressure within the lower water-bearing layer. 
     
     
         24 . The method of  claim 23 , wherein the determining the gas-oil contact depth and the determining the oil-water contact depth includes determining a pressure vs. depth profile within the gas-filled region, determining a pressure vs. depth profile within the oil-filled region, and determining a pressure vs. depth profile within the lower water-bearing layer, wherein the determining the gas-oil contact depth includes determining an intersection point between the pressure vs. depth profile within the gas-filled region and the pressure vs. depth profile within the oil-filled region, and further wherein the determining the oil-water contact depth includes determining an intersection point between the pressure vs. depth profile within the oil-filled region and the pressure vs. depth profile within the lower water-bearing layer. 
     
     
         25 . The method of  claim 22 , wherein the method further includes determining a target depth for the wellbore within the reservoir, wherein the target depth is based, at least in part, on the gas-oil contact depth and the oil-water contact depth, and further wherein the method includes determining a target pressure within the reservoir at the target depth. 
     
     
         26 . The method of  claim 25 , wherein the method further includes:
 (i) extending the length of the wellbore to locate the directional drilling assembly within the reservoir;   (ii) detecting a reservoir pressure within the reservoir;   (iii) comparing the reservoir pressure to the target pressure; and   (iv) adjusting the orientation of the directional drilling assembly based, at least in part, on the comparing the reservoir pressure to the target pressure.   
     
     
         27 . An extended-reach drilling operation, comprising:
 a reservoir that is present within a subsurface region;   a wellbore that extends between a surface region and the reservoir;   a directional drilling assembly; and   a controller that is programmed to control the operation of the directional drilling assembly using the method of  claim 1 .