The challenges with manual salinity monitoring

During long-duration flowbacks, the salinity of the water increases over time as the proportion of completion slickwater returned is reduced and more reservoir water is produced. The change in salinity cannot be assumed to be linear, but rather is logarithmic and depends on the surface return rates. As the salinity changes, the water properties change, which has conventionally required performing in situ reference sampling to maintain the accuracy of the flow rate measurement by the PhaseTester portable multiphase well testing equipment or Vx Spectra surface multiphase flowmeter.

Especially for long-flowback well tests, an operator in the Midland Basin wanted a high-accuracy automated solution instead of requiring periodic manual water sampling and analysis at remote wellsites.

The inclusion of continuous salinity measurements from the sensor would eliminate the need for manual sampling while improving the accuracy of the flow rate calculation, in turn optimizing the length of well cleanup and flowback.

Elimination of manual sampling to improve safety and reduce cost

The AquaWatcher Surface sensor was installed at the wellsite for a long-term flowback test. It reported continuous measurement of the water conductivity to the data acquisition computer, which calculated the salinity value as the NaCl equivalent. The real-time salinity was then used to automatically update the flowback water properties.

No longer were personnel required to visit the remote wellsite and manually measure and enter the salinity value. The accuracy of the flow rate measurements was improved for understanding the results of the flowback test while operating costs for site visits were significantly reduced.