Shutting in wells requires coordination between the office-based operating team and the pumpers to know which wells need to be stopped/closed and secured. Each pumper usually has 20-50 wells to check a day and can drive up to 400 miles to get the job done. If the well does not have SCADA, the operator likely has a pumper going to each well once a day to read fluid rates and pressures and to check the location for leaks or damage (from vandalism, bad weather, cows scratching an itch…). If the well is turned off for more than a few days or if the well has a significant amount of liquids on site in tanks, the operator may also send a technician (or “pumper” or “operator”) out to run through a checklist for securing the well long-term (flushing lines, having liquids hauled away, removing hazardous chemicals, etc.). If a well has SCADA installed, the production can be stopped remotely (pumping unit turned off, a valve on the production line closed, etc.), as easily as a few clicks on a phone app. It’s like Apple HomeKit or Alexa for the well. SCADA (sometimes called “automation”) is technology installed on the equipment at the well which lets operators remotely view production rates and pressures, turn engines on or off, open and close valves, and adjust parameters like pumping speed.
Typically, horizontally fractured wells use either gas lift or ESPs in the beginning if the well needs help getting the water out of the well. This lift helps the liquid get from the bottom of the well to the top either by making the liquid not as heavy (gas lift, soap sticks), by pushing it up the well from the bottom (beam/rod pumps, electronic submersible pumps, plunger lift), or by sucking it up the well from the top (wellhead compression, velocity strings). The help is in the form of “artificial lift” (as opposed to the well flowing liquid to the surface by itself). Sometimes the reservoir just doesn’t have enough pressure to push the water up, and we need to give it some help. When water is pushed down hole, the reservoir then has to push it back up before the oil or gas can follow behind it. A gallon of fresh water weighs about 8.3 lbs, while a gallon of gasoline weighs only 6 lbs (and a gallon natural gas is a mere fraction of that). Water is heavier than oil and gas, something we’ve all seen when the salad dressing separates with the oil on top. The bottom line is a LOT of water is pumped down into the reservoir in order to fracture a reservoir, typically 2-8 million gallons of water per well. To transport the sand into the fractures, the sand is suspended in water and pumped down the pipe in a massive operation. These fractures are created by pumping really hard against the reservoir rock with water ("hydraulic"), making a break ("fracture") in the rock, then filling that fracture with sand to keep it open ("propped"). 99% of wells drilled in the US today are horizontally drilled unconventional wells with a bunch of man-made propped hydraulic fractures.