A More Efficient Way of Plug Debris Cleanout
By Bram Alackness | Product Line Supervisor | March 14th, 2025
Cleaning out wellbore plug debris and frac sand can be messy and pose considerable risks to worker safety, production, and the environment. In a typical horizontal well where the common plug-and-perf method is used, several bridge plugs are set at intervals to isolate the various lateral stages. Once the hydraulic fracturing process is complete, the plugs set in the wellbore are then typically drilled out utilizing either a coiled-tubing unit or a hydraulic completion unit. Removing these plugs allows an open path for hydrocarbons to travel from the formation up through the wellbore. The drillout process involves careful coordination of the various service companies on location, particularly between the flowback company (TETRA) and the rig company. During the drillout phase, constant circulation of fluid in and out of the wellbore must be maintained while clearing out plug debris and frac sand. If this operation is not performed properly, an accumulation of debris in the wellbore can lead to issues like stuck pipe and loss of well control.[*]
Conventional Cleanout
A conventional drillout package generally entails three equipment skids—the main manifold, a backup ‘panic’ manifold, and a debris catcher—all of which must be moved into place by forklift and plumbed together with high-pressure flowlines. Operating and servicing these systems is, at minimum, a two-man operation requiring frequent manual operation of valves and removal of filter screens. These specific tasks require employees be constantly stepping over and reaching around high-pressure flowlines ranging from 1,000 to 3,000 PSI. The manual process not only exposes workers to potential pressure release, but also increases the risk of spills that can harm the immediate environment, bringing operations to a halt.
Automated Cleanout
Recognizing the hazards and risks of conventional systems, TETRA innovated the industry’s first auto-drillout system, a revolutionary total solution with all the necessary components on a single 8 x 40-foot trailer-mounted skid that automatically flushes out plug parts and sand during the drillout operation.
Designed to better manage wellbore pressure and operate more safely, the TETRA Auto-Drillout System reduces the risk of bodily injury by greatly reducing the need for onsite personnel to manually turn valves and remove and replace debris-catcher screens. Operated from a mobile command center trailer, it also significantly reduces exposure to high-pressure zones and potentially trapped pressure. With a proprietary flushing process that prevents surging from the formation, the system provides thorough cleanout of debris and sand, thereby reducing the potential for stuck work-strings and nonproductive time (NPT).
Easily transported and put in place, the single-skid unit has a tight footprint and is low-maintenance to avoid costly downtime. Its fully integrated piping includes a debris catcher with automated flush sequencing, a multi-segment manifold system, and an integrated panic manifold. These components are all linked to a programmable logic controller with connectivity for remote monitoring and control. Users can access the control panel from a mobile device to monitor and control operations—a feature that is especially beneficial when one must make adjustments while away from the worksite. The smart system also maintains historical data logs, capturing data points such as pressures, valve actuations, alarms, and tank levels.
Manual Screen-Pull vs. Automated Flushing
A screen cleanout for a conventional package typically requires at least two people to conduct and approximately four minutes to service each flush cycle. The manual steps are: divert flow, isolate the barrel, bleed down pressure, remove the screen from the system, clean out the screen, reinsert the screen, and restore flow to the newly cleaned line. The manual operation exposes workers to the risk of hand or back injury as well as the hazard of potentially trapped pressure.
By contrast, the TETRA Auto-Drillout System requires only one person to operate and performs each cleanout cycle in approximately 40 seconds. The automated steps are:
[1] A transducer senses a pressure differential indicating the presence of debris.
[2] Flow automatically diverts from the primary to the secondary line.
[3] The main flowline downstream of the manifold closes and momentarily diverts flow to flush debris from the debris-catcher screen.
[4] When the flushing cycle is complete, flow automatically reverts from the secondary to the primary line.
Case Study 1: 40% Reduction in Rig-up
First deployed to Appalachia in Summer 2022, the TETRA Auto-Drillout System was used on 13 unconventional gas wells. In four months of incident-free operation, the unit cleaned out more than 2,300 plugs without the need to pull a single screen and without any nonproductive time. In terms of measurable value for the operator, the system overall reduced rig-up/rig-down time 40%, exposure to risk 33%, and wear on system components 65%, yielding a significant reduction in operational cost and improvement of safety.
Case Study 2: Over 15,000 Plugs Cleaned Out
The same operator again commissioned use of the TETRA Auto-Drillout System in the Appalachian basin. Over the course of some 30 months, the system serviced 178 wells and cleaned out a total of 15,425 plugs, all without the need to pull and clean out a single debris-catcher screen and without incurring any nonproductive time or HSE incidents.
Safely operated from the mobile command center trailer, the TETRA system eliminated manual control of valves and pulling debris-catcher screens. Regarding efficiency, it enhanced wellbore pressure management during drillout, enabling pre-programmed valve sequencing and maintaining consistent pressures and flowrates without large swings when switching the flow between the two lines of the dual system.
Ultimately, the TETRA Auto-Drillout System significantly reduced the operator’s exposure to safety and environmental risk as well as onsite headcount—delivering exceptional value to their gas-well development.
[*] Haithem Trabelsi, et al (2021), “Bridge Plug Drillouts Cleaning Practices: An Overview,” Natural Resources, Vol. 12, No. 2, pp. 19–33, February 2021.
