An Unattended SWD Operation
With the price of oil falling to lows not seen since 2009, producers are putting pressure on SWD operators to reduce the price charged for frack flow-back and produced water disposal. In order to run more efficient SWD plant operations and reduce man-power costs, SWD companies are turning to automation so that operators are not needed full-time on location.
PREFERRED CONTROLS an automation company in Minot, North Dakota has the solutions to lean out operating costs while maintaining control. When running an unmanned plant there are several processes that need to be monitored. First the trucking companies that will be using the facility need to enter their assigned I.D. code into a touch screen along with the truck number, barrels of water, type of water and the asset where the water was generated. When the data is entered correctly the driver will be able to start the offload process if all plant conditions are correct. In order for the offload to proceed tank levels will be monitored using level transmitters located on the tank battery to assure there is room for the incoming water. Pressure devices will be placed across the primary filters used for removing large sediment. When the pressure differential across the filters drops to a predetermined level detecting a plugged filter condition, a solenoid valve located near the filters will shut and the offload pumps will be stopped and an alarm sent requiring intervention by the SWD operator.
A flow meter will be added to each offload line to assure that the correct amount of water entered by the driver has been delivered. There are several types of flow meters that can be used for this application. One meter that can be used is a corriolis meter that has the ability to detect the viscosity of the incoming fluid in order to identify and measure the types of fluid actually delivered by the driver and verify that the SWD can process the waste.
Being able to identify and manifest each load accurately is a large challenge for the operator of an unattended SWD. Not only is it important to invoice generating oil and gas companies but it is absolutely vital to protect the company’s disposal well from damage by inappropriate wastes. Intake volumes and generator data can be sent automatically to regulator websites where this is needed.
Within the tank battery multi-phase level monitors can be installed in the gun barrel and in water tanks as needed. These sensors will measure levels for water and oil and this data can be passed on to operators and distant offices. Fluid levels can be used to automatically trigger transfer pumps to pump off oil or water.
Other plant functions such as downhole pumping and process pressures and flow can be monitored . A data base will keep track of all activities at the plant and can also be accessed remotely or locally. By using a PLC control panel along with cameras and remote telemetry such as radios, Satellite, or internet , the plant conditions can be viewed remotely via laptop, note book, or cell phone. Also alarms can be sent to notify personal of any conditions that they wish to be alerted on. The alarming can be done via phone or e-mail and texting to whomever the would like to notify of plant conditions. Alarms are particularly important for unattended facilities.
The plant can be operated in full automatic mode when all the process conditions are correct, and will shut the plant down when an upset condition is detected . The most common upset will be plugged filters either at the load-outs or within the pump building. When the filters become plugged either a driver or company personal will need to change them and reset alarms. When operating several SWD plants, the company can reduce the number of operators needed by using automation described above to run the plants. Using and storing video surveillance can track all plant activity and will support local data entry or hardcopy tickets to verify incoming traffic.
PREFERRED CONTROLS will be happy to discuss any questions on SWD automation that you may have.
Marian M. Langhus, PhD and Bruce G. Langhus, PhD at SWDI 918-645-8943
Pete Desautel at Preferred Controls, 320-224-1217