Data Driven Journey to Optimize Offshore Sand Management

Sand from offshore wells erodes chokes and piping and damages produced-water injection pumps, yet most locations have no sand sensors to show whether desanders are working. The team piloted filter and hydrocyclone desanders at a wellhead platform. They created a low-cost performance coefficient from standard hydrocyclone equations, fixed control and hardware problems on an existing desander, and automated the reading of acoustic sand detectors with changepoint algorithms. Hydrocyclones clearly outperformed filters, and the operating changes gave smoother flow and lower vibration in the downstream pumps.

Key results

Filter units plugged quickly and their pressure drop rose steeply with gas rate, while hydrocyclones gave stable separation that was sensitive to gas fraction and particle size
Deviations in the k-factor exposed a misaligned liner holder plate that let separated sand flow back into the water stream; a re-fabricated plate fixed it
The flow-primary control scheme smoothed the feed to the desander and reduced vibration at the downstream water injection pumps
With calibration, acoustic sand detectors reached about ±25% accuracy. Automated baselining identified two high-sand wells and let previously shut-in wells return to production smoothly

Approach

Pilot-tested filter and multi-cone hydrocyclone desanders downstream of the choke manifold on a wellhead platform, with acoustic sand detectors installed upstream and downstream
Simplified the Plitt and Stairmand models and a vendor sizing equation into a pseudo-performance coefficient (k-factor), fitted to field data and tracked on a dashboard alongside pump vibration
Ran field optimization trials: number of liners, new liner holder plates and O-rings, underflow throttling, accumulator drain frequency, gas-to-liquid ratio and particle size analysis
Changed the control logic upstream of the existing desander from level-only control to flow control with a level override, because the control valve sits upstream of the desander
Automated acoustic baseline (zero) detection with online and offline changepoint algorithms in R and Python, and used the University of Tulsa erosion equation to set acceptable sand rates

The problem

Offshore facilities lacked a practical way to monitor and improve desander efficiency without dedicated sand sensors, which put downstream equipment such as water injection pumps at risk.

Tools & methods

Plitt hydrocyclone modelStairmand cyclone modelacoustic sand detectorschangepoint detection (R: cpm, bcp, ecp; Python: ruptures, OCPDET)University of Tulsa / DNV erosion equationsPID / override control tuningmonitoring dashboard

Summary written for this site from the published paper. For figures, data and the full method, read the paper on OnePetro.