Manage choke erosion during flowback and demonstrate clean flow at completion

Flowback operations following the refracturing of a well often encounter significant sand production that erodes choke equipment and causes loss of flow rate control, which ultimately leads to reservoir damage and poor well performance. When completing a job near Longview, Texas, an operator wanted to monitor the flowback operation in real time (as opposed to the standard one-hour intervals) to better manage choke integrity, prevent washouts, and mitigate risks during during postfracturing cleanup. In addition, strict pipeline regulations required the operator to demonstrate less than 1% solids by volume at the completion of flowback, which added to the challenge.

Run PhaseTester equipment with Vx technology for real-time monitoring

For the flowback operations, Schlumberger recommended the deployment of PhaseTester portable multiphase well testing equipment with Vx multiphase well testing technology, in addition to the standard flowback equipment to integrate real-time multiphase metering and solids quantification capabilities. PhaseTester equipment with Vx technology uses a combination of low-energy gamma radiation measurements along with fluid dynamics models to determine flow rates of individual fluid phases without separation.

Capable of providing high-resolution data (less than 1-second interval, if necessary), Vx technology is the ideal choice for real-time monitoring of flow rates. In this flowback operation, unexpected increases in real-time flow rate data were correlated to choke erosion, alerting the need for immediate replacement of the washed-out choke stem to prevent loss of well control.

Achieved clean-flow target sooner, reduced cost of operation

Real-time data analysis enabled the operator to recognize and react to choke erosion early, therefore the planned choke schedule and flow rates were successfully maintained throughout the flowback operation. With the added sand quantification capabilities of Vx technology, flow conditions were closely monitored and end of cleanup was determined sooner than it would have been using conventional technology. All flowback objectives and pipeline solids limits were met within 9 days of total cleanup time, and crew was released early, reducing flowback operation cost.

Real-time monitoring also enabled the interpretation of sand behavior in the flow path. The sand production spiked seconds after choke changes, which indicated that the increase in sand production was most likely due to the displacement of sand from the vertical portion of the wellbore, instead of sand from the matrix or horizontal portions of the well. Quantification of overall sand mass using Vx technology correlated accurately with the quantity of sand estimated by the standard hourly sampling technique.