At Balance TE DAPC IPM

When the window within which the drilling pressure must stay is on the order of a percent or less of the absolute BHP value, controlling it becomes a safety and time critical operation.

Pressure control is performed by the Intergrated Pressure Manager (IPM) at the heart of which is a programmable-logic-controller (PLC). The PLC collects measurements and feedback from the chokes, monitors and adjusts their positions, and controls the backpressure pump. It uses the same safety critical process control technology found in refineries and on production platforms.

The IPM subsystem consists of the PLC software and hardware linked via a high speed bus to the hydraulic power units, DAPC instrumentation network, data acquisition network, hydraulics model, and the human machine interface (HMI).

Two-way communication between the IPM and the real-time model supports the essential exchange of hydraulics and BHP data along with the well and rig data.

Maintaining the BHP at the setpoint at all times is the IPM's most important task. The setpoint - the pressure control point at a specific depth in the well, typically at the bit - guides the pressure manager’s every action.

If the BHP deviates from the setpoint the IPM automatically adjusts the choke position to correct the backpressure. In normal drilling mode the hydraulics model provides frequent updates so that the IPM can respond to pressure changes in a timely manner and maintain a constant BHP. It calculates the BHP once a second and calibrates itself every time it receives downhole pressure while drilling (PWD) data.

Together the IPM, the hydraulics model, the choke manifold, and the backpressure pump form an advanced control system that provides uninterrupted, accurate automated pressure management.