Measuring pressure of lubricant in downhole drill head with the HI5000 Downhole Pressure Transmitter

Measuring lubricant pressure inside a downhole drill head is a small but vital task that keeps drilling rigs running safely, efficiently and profitably. In the hostile environment of a borehole — where extreme temperature, high vibration, corrosive fluids and space constraints are the norm — selecting the right pressure sensor is critical.

Why lubricant pressure matters

Lubricant (or drilling fluid) pressure within the drill head affects bearing lubrication, seal life and the efficient transmission of torque. Too low a pressure risks metal-to-metal contact and premature wear; too high a pressure can indicate blockage, seal failure or other faults that quickly cascade into costly downtime. Continuous, reliable pressure monitoring therefore provides early warning of developing problems and enables condition-based maintenance rather than reactive repairs — saving time and reducing the risk of catastrophic failures.

The challenges of downhole measurement

Downhole measurement presents several unique challenges: high static and transient pressures, temperatures that may exceed 200°C, corrosive or contaminant-laden fluids, intense shock and vibration, and severe space limitations inside the drill head assembly. Any transmitter chosen must survive these stresses while delivering stable, repeatable data over long deployment periods. The HI5000 Downhole Pressure Transmitter from ESI Technology Ltd is purpose-built for this job: compact, robust and engineered to give accurate, long-term lubricant-pressure readings where conventional sensors would fail.

What makes the HI5000 suitable?

• Compact form factor. The HI5000 is highly compact (maximum length approximately 57–58 mm), making it straightforward to fit into confined downhole locations without redesigning the drill head assembly.
• Robust materials and construction. The transmitter uses corrosion-resistant, NACE-certified materials and an all-welded, sealed construction that prevents ingress and resists the chemical attack common in drilling environments. That durability supports long service life and reduces replacement frequency.
• Advanced sensing element. At the heart of the HI5000 is silicon-on-sapphire sensor technology, a single-crystal sensing element known for low hysteresis, excellent high-temperature stability and exceptional long-term performance. This technology helps deliver accurate readings across wide temperature and pressure ranges critical for lubricant monitoring downhole.
• High temperature and pressure capability. The device is rated for extreme operating conditions (temperatures up to around 200°C and pressure ranges suited to downhole applications), allowing operators to monitor lubricant pressure reliably even in geothermal or high-pressure drilling scenarios.

Practical benefits on rig operations

Fit-for-purpose sensors like the HI5000 enable continuous condition monitoring and fast diagnostics. Operators can spot gradual lubricant starvation, detect abnormal pressure spikes caused by debris or seal failures, and correlate pressure trends with vibration and temperature data to pinpoint root causes. The compact size and ruggedness reduce installation time and lower the need for frequent retrievals for maintenance — a real operational advantage on costly drilling campaigns.

Conclusion
Accurate lubricant pressure measurement inside a downhole drill head is essential to protecting rotating parts, preventing unplanned downtime and optimising maintenance windows. The HI5000 Downhole Pressure Transmitter from ESI Technology Ltd combines a compact footprint, corrosion-resistant construction and silicon-on-sapphire sensing to meet the exacting demands of downhole lubricant monitoring — helping engineers turn raw data into better operational decisions.