Rotary Steering with Multiple Contact Points

Abstract

A system in which a drill string is disposed within a wellbore that extends from a wellsite surface to a subterranean formation. At least three rotary steerable system (RSS) modules are collectively coupled in series between the drill string and a drill bit. Each RSS module includes at least three steering pads spaced circumferentially apart around a perimeter of the RSS module, and a valve operable to sequentially actuate the steering pads. The system also includes a controller operable to independently actuate the valve of each RSS module simultaneously.

What is claimed is: 
     
         1 . A system for drilling a wellbore, comprising:
 a rotary steerable system (RSS) at least indirectly coupled between a drill string collar and a drill bit, wherein the RSS comprises:
 a first section comprising at least three first steering members and a first valve operable to sequentially actuate the first steering members; 
 a second section comprising at least three second steering members and a second valve operable to sequentially actuate the second steering members; and 
 a third section comprising at least three third steering members and a third valve operable to sequentially actuate the third steering members. 
   
     
     
         2 . The system of  claim 1  wherein the RSS further comprises a controller operable to control the first, second, and third valves to, simultaneously:
 sequentially actuate the first steering members to operatively urge the first section in a first azimuthal direction; 
 sequentially actuate the second steering members to operatively urge the second section in a second azimuthal direction substantially different from the first azimuthal direction; and 
 sequentially actuate the third steering members to operatively urge the third section in a third azimuthal direction substantially different from the second azimuthal direction. 
 
     
     
         3 . The system of  claim 2  wherein the controller is further operable to control the first, second, and third valves to, simultaneously:
 actuate the first steering members to operatively centralize the first section within the wellbore; 
 actuate the second steering members to operatively centralize the second section within the wellbore; and 
 sequentially actuate the third steering members to operatively urge the third section away from a longitudinal axis of the first and second sections. 
 
     
     
         4 . The system of  claim 1  wherein the RSS comprises:
 a first flexible component flexibly coupling the first and second sections; and 
 a second flexible component flexibly coupling the second and third sections. 
 
     
     
         5 . The system of  claim 1  wherein the RSS comprises:
 a first joint disposed between the first and second sections; and 
 a second joint disposed between the second and third sections. 
 
     
     
         6 . An apparatus, comprising:
 a drill string disposed within a wellbore that extends from a wellsite surface to a subterranean formation;   a drill bit;   at least three rotary steerable system (RSS) modules collectively coupled in series between the drill string and the drill bit, wherein each RSS module comprises:
 at least three steering members spaced circumferentially apart around a perimeter of the RSS module; and 
 a valve operable to sequentially actuate the steering pads; and 
   a controller operable to independently actuate the valve of each RSS module simultaneously.   
     
     
         7 . The apparatus of  claim 6  wherein the at least three movable steering pads of each RSS module are disposed at substantially the same axial position. 
     
     
         8 . The apparatus of  claim 6  wherein the valve is operable to sequentially actuate the steering pads by sequentially directing fluid to actuators each associated with a corresponding one of the steering pads. 
     
     
         9 . The apparatus of  claim 8  wherein the fluid directed to the actuators is received from equipment disposed at the wellsite surface. 
     
     
         10 . The apparatus of  claim 6  wherein the controller is operable to actuate the valves of the RSS modules to, simultaneously:
 sequentially actuate the steering pads of a first one of the RSS modules to operatively urge the first one of the RSS modules in a first azimuthal direction; 
 sequentially actuate the steering pads of a second one of the RSS modules to operatively urge the second one of the RSS modules in a second azimuthal direction substantially different from the first azimuthal direction; and 
 sequentially actuate the steering pads of a third one of the RSS modules to operatively urge the third one of the RSS modules in a third azimuthal direction substantially different from the second azimuthal direction. 
 
     
     
         11 . The apparatus of  claim 10  wherein:
 the second azimuthal direction is substantially opposite the first azimuthal direction; and 
 the third azimuthal direction is substantially similar to the first azimuthal direction. 
 
     
     
         12 . The apparatus of  claim 11  wherein the first and third azimuthal directions are each angularly offset from the second azimuthal direction by an amount ranging between about 175 degrees and about 185 degrees. 
     
     
         13 . The apparatus of  claim 10  wherein the controller is further operable to control the valves of the RSS modules to, simultaneously:
 actuate the steering pads of the first one of the RSS modules to operatively centralize the first one of the RSS modules within the wellbore; 
 actuate the steering pads of the second one of the RSS modules to operatively centralize the second one of the RSS modules within the wellbore; and 
 sequentially actuate the steering pads of the third one of the RSS modules to operatively urge the third one of the RSS modules away from a longitudinal axis of the first and second ones of the RSS modules. 
 
     
     
         14 . The apparatus of  claim 6  further comprising:
 a first flexible component flexibly coupling first and second ones of the RSS modules; and 
 a second flexible component flexibly coupling the second one of the RSS modules and a third one of the RSS modules. 
 
     
     
         15 . The apparatus of  claim 6  further comprising:
 a first joint disposed between first and second ones of the RSS modules; and 
 a second joint disposed between the second one of the RSS modules and a third one of the RSS modules. 
 
     
     
         16 . The apparatus of  claim 6  wherein the drill bit, the at least three RSS modules, and the controller are collectively operable to extend the wellbore with a dogleg of up to twenty degrees per 100 feet (30.5 meters). 
     
     
         17 . A method, comprising:
 conveying apparatus within a wellbore that extends from a wellsite surface to a subterranean formation, wherein the apparatus comprises a drill string, a drill bit, and at least three rotary steerable system (RSS) modules collectively coupled in series between the drill string and the drill bit, and wherein each RSS module comprises:
 at least three steering pads spaced circumferentially apart around a perimeter of the RSS module; and 
 a valve operable to sequentially actuate the steering pads; and 
   operating a controller to independently actuate the valve of each RSS module to, simultaneously:
 sequentially actuate the steering pads of a first one of the RSS modules to operatively urge the first one of the RSS modules in a first azimuthal direction; 
 sequentially actuate the steering pads of a second one of the RSS modules to operatively urge the second one of the RSS modules in a second azimuthal direction substantially different from the first azimuthal direction; and 
 sequentially actuate the steering pads of a third one of the RSS modules to operatively urge the third one of the RSS modules in a third azimuthal direction substantially different from the second azimuthal direction. 
   
     
     
         18 . The method of  claim 17  further comprising operating the controller to control the valves of the RSS modules to, simultaneously:
 actuate the steering pads of the first one of the RSS modules to operatively centralize the first one of the RSS modules within the wellbore; 
 actuate the steering pads of the second one of the RSS modules to operatively centralize the second one of the RSS modules within the wellbore; and 
 sequentially actuate the steering pads of the third one of the RSS modules to operatively urge the third one of the RSS modules in an azimuthal direction away from a longitudinal axis of the first and second ones of the RSS modules. 
 
     
     
         19 . The method of  claim 17  further comprising, prior to conveying at least a portion of the apparatus within the wellbore, coupling the RSS modules in series between the drill string and the drill bit. 
     
     
         20 . The method of  claim 17  further comprising, prior to conveying at least a portion of the apparatus within the wellbore:
 coupling a first flexible component between first and second ones of the RSS modules; and 
 coupling a second flexible component between the second one of the RSS modules and a third one of the RSS modules.