Rotary Steerable Systems
Continuous rotation of the drill string, along with motor assist, gives maximum performance to the bit. Cutting out slide time while continuing to steer while rotating helps to increase overall ROP
Reach Further Depths with Rotary Steerable Systems
The methods used to direct the well path fall into two broad categories, these being “push-the-bit” or “point-the-bit”. Push-the-bit tools use pads on the outside of the tool which press against the well bore thereby causing the bit to press on the opposite side causing a direction change. Point-the-bit technologies cause the direction of the bit to change relative to the rest of the tool by bending the main shaft running through it. They both require some kind of non-rotating housing or reference housing in order to create this deflection within the shaft.
There are many advantages to using this technology for both main groups of users: geologists and drillers. Continuous rotation of the drill string allows for improved transportation of drilled cuttings to the surface resulting in better hydraulic performance, better weight transfer for the same reason allows a more complex bore to be drilled, and reduced well bore tortuosity due to utilizing a more steady steering model. The well geometry therefore is less aggressive and the wellbore (wall of the well) is smoother than those drilled with a motor. This last benefit concerns geoscientists, because better measurements of the properties of the formation can be obtained, and the drillers, because the well casing or production string can be more easily run to the bottom of the hole.
- Ability to use a downhole motor for motor assist in order to increase hp and torque at the bit
- Expanded revolution rate limits, supporting up to 350 rev/min for higher ROP and stick and slip control
- Six-axis continuous inclination and azimuth measurements for better true-vertical-depth (TVD) definition and accurate well positioning
- A downlink is used to change steering commands, and an uplink is sent for confirmation of the command change
Rotary Steerable Technology has enhanced durability for severe downhole conditions. It can drill from shoe to TD in a single run, reducing operating days. It provides extra reliability in complex operations where stick/slip, severe shock and torque, and complex hydraulic systems are significant risks.