Lil4X
Elio Addict
Thanks guys for the props . . . Waterflood operations are typical means of extending the life of old wells. As water (typically saltwater) drives oil up into the hard cap from below, wells on the fringes of the reservoirs begin to produce large quantities of saltwater mixed with dwindling quantities of oil. These "stripper" wells can still be economically produced, if the owner is willing to invest in water separation equipment at the surface to skim off the oil from the water. I've sat on wells out in the Jal field in Southeastern New Mexico that were making maybe 250 barrels of water to 14 barrels of oil per day, which was about break-even for oil when WTI (West Texas Intermediate, a global "quality" standard) was selling for about $135/barrel. It was just enough profit to keep the pump running and separate the small quantity of oil from the water - barely. The owner elected to keep that well on stream - for a time - so long as more water intrusion (or falling oil prices) made it unprofitable. Now, these wells were drilled in the '40's and early '50's and were not much deeper than 8K feet. They'd produced oil for nearly 30 years and like a faithful old mule, needed to be put down before they became even more of a liability.
Rather than Plug and Abandon the well (known as P&A), a rather expensive process that permanently seals off the well by placing a concrete plug just above the producing interval (to fulfill state and federal abandonment laws). If the well is located "downhill" from recoverable quantities of oil, it can be repurposed as injection wells by cleaning and re-plumbing to feed the produced saltwater from other, somewhat shallower wells, back down into the formation. That's a win-win for the operator . . . he is disposing of that saltwater that's still contaminated with trace amounts of oil, and using it to "herd" oil toward other wells located "higher" in the reservoir. The net result is to remove fewer liquids from the producing formation while making other nearby wells more profitable by re-injecting the larger part of the produced fluids back into the ground. The idea here is to make those "disposal" wells work for you rather than be a liability. Although there is some net loss to the formation, it's not like producing vast amounts of saltwater that then have to be hauled (or piped) away.
That can become a long-term issue too. I live about 2 miles from an oilfield that was drying up in the late '40's and today has only a few pumping wells - maybe three or four in several Sections of land. A 5" pipeline runs through our subdivision about a block South of my home that is STILL carrying saltwater from the old oilfield to our West. It had been rusting out and leaking for several years before the state forced the oil operator to either repair the line or seal it and find another way to dispose of what are still rather large quantities of saltwater. The leaking line runs parallel to a neighboring street, and the salt is killing several blocks of big old pecan trees that border the street and arch over it to meet similar trees on the other side. The community association and finally the city had to sue the operator to take care of the problem before lawns and even flower beds were poisoned with increasing quantities of salt. For a while it looked like Chernobyl over there as large amounts of soil had to be dug up and hauled away because they were heavily contaminated. Now the topsoil's been replaced, as has the sod and new pecans planted. It'll still be years before they reach maturity, but the solution's at hand. Those old wells are being P&A'd this year. Talk about reaching the point of diminishing returns . . . . With oil under $60/bbl, it's hard to understand why it wasn't done before.
Rather than Plug and Abandon the well (known as P&A), a rather expensive process that permanently seals off the well by placing a concrete plug just above the producing interval (to fulfill state and federal abandonment laws). If the well is located "downhill" from recoverable quantities of oil, it can be repurposed as injection wells by cleaning and re-plumbing to feed the produced saltwater from other, somewhat shallower wells, back down into the formation. That's a win-win for the operator . . . he is disposing of that saltwater that's still contaminated with trace amounts of oil, and using it to "herd" oil toward other wells located "higher" in the reservoir. The net result is to remove fewer liquids from the producing formation while making other nearby wells more profitable by re-injecting the larger part of the produced fluids back into the ground. The idea here is to make those "disposal" wells work for you rather than be a liability. Although there is some net loss to the formation, it's not like producing vast amounts of saltwater that then have to be hauled (or piped) away.
That can become a long-term issue too. I live about 2 miles from an oilfield that was drying up in the late '40's and today has only a few pumping wells - maybe three or four in several Sections of land. A 5" pipeline runs through our subdivision about a block South of my home that is STILL carrying saltwater from the old oilfield to our West. It had been rusting out and leaking for several years before the state forced the oil operator to either repair the line or seal it and find another way to dispose of what are still rather large quantities of saltwater. The leaking line runs parallel to a neighboring street, and the salt is killing several blocks of big old pecan trees that border the street and arch over it to meet similar trees on the other side. The community association and finally the city had to sue the operator to take care of the problem before lawns and even flower beds were poisoned with increasing quantities of salt. For a while it looked like Chernobyl over there as large amounts of soil had to be dug up and hauled away because they were heavily contaminated. Now the topsoil's been replaced, as has the sod and new pecans planted. It'll still be years before they reach maturity, but the solution's at hand. Those old wells are being P&A'd this year. Talk about reaching the point of diminishing returns . . . . With oil under $60/bbl, it's hard to understand why it wasn't done before.
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