Restoring Idle Wells

By: Andy Maslowski
Jan/Feb 2010

 
Oil and gas wells are not just holes in the ground lined with steel casing and cement. They are energy mines, equally important to any power source generated by a bushel of corn, a windmill or a solar panel array. As such, each well should produce to its full potential.

More second chance wells are re-completed, rather than re-entered after going through the P&A process.

 
This should make us wonder: how much American petroleum is sitting behind pipe in wells drilled years ago? Probably millions of barrels of crude oil and billions of cubic feet of natural gas. Some of it is worth pursuing.
 
Don’t believe everything you see on TV or the Internet (or read in this article!). We need petroleum. If you don’t believe it, stop driving your car or truck, stay off airplanes, or don’t use natural gas to cook your food or heat your water or home. See how long you can live without it!
 
Abandoned wells
There are thousands of wells in producing states that have been abandoned for many months or years. While due diligence may be required in each producing state regarding idleness or plugging status, some wells slip through the system.
 
They may be pumped or turned on occasionally to maintain their productivity status or keep a lease active. Or there may be a legal problem that halts activity such as a company bankruptcy or financial troubles, change of ownership, death, divorce, etc. Or a well could face some kind of production, equipment, casing or sucker rod failure. How many wells have perforations in the wrong place? How many were poorly maintained or serviced? No one knows for sure.
 
Whatever the problem, many wells can be re-completed or re-opened to tap into the existing reserves of oil or gas that lie below the surface. Most producing states encourage this, or at least provide a permitting process to do so.
 
For example, the Railroad Commission of Texas (RRC) said 1,613 re-completions and 447 re-entries were reported for the period January 2009 through October 2009 in the Lone Star State. This combined total of 2,060 represents about a 22 percent increase when compared with 1,690 similar completions during the first 10 months of 2008.

An individual or a company must do their homework before re-entering an existing well or one that has been plugged.

 
The RRC defines a re-completion as a “workover to a separate zone” or a “workover to a multiple completion.” It may also include attempts to deepen, plugback, sidetrack or co-mingle production from different geologic rock units. “A re-entry is going back into a wellbore that has been plugged to the surface.”
 
Naturally, not all re-completions and re-entries were successful. But most were — including 868 oil well re-completions, 209 oil well re-entries and 636 natural gas re-completions.
 
Looking over data from other states, it appears permits for re-entries, converts, deepenings, plugbacks, re-openings, etc., are contributing to more oilfield-related business. All of this is a beautiful thing for the nation, the producers and all involved! It keeps, or returns, a well to active status. The alternative, plugging and abandonment, although necessary, does not help the cash flow or the mythical drive toward American energy independence!
 
Many re-completions and re-entries are targeting oil wells and not natural gas wells. Just look again at the statistics from Texas. Oil remains the favorite. It appears higher prices, at $70 or 80 a barrel, or more, is a good incentive to re-examine existing wells. Wells plugged in the 1980s or 1990s, during periods when oil prices dipped, may now be worth a second look.
 
Research
An individual or a company must do their homework before re-entering an existing well or one that has been plugged. However, to do so, literally, can be the modern equivalent of opening Pandora’s box!
 
Let’s look at plugged wells first. Be very careful going back into these holes because there are many reasons why they were plugged in the first place. Most likely, the reservoirs are depleted. Or it could just be a dry hole or one likely to produce an “ocean” of salt water if perforated in the wrong place. But the well could also be a lost hole, have casing troubles, stuck fish in the hole, or dozens of other problems.
 
To find the ideal plugged well to re-enter, examine well records, wireline logs and oil and gas well location maps. There are cases of successfully re-entering wells 50 years old or older, but generally the older the well, the likelihood of problems increases.
 
Historically, somewhere in the neighborhood of 3 million wells have been drilled in the USA in search of oil or gas. Two-thirds of these, some 2 million wells, have been abandoned. One U.S. EPA study estimated as many as 200,000 may not have been properly plugged. Most of these were drilled 50 years ago or longer, before there were state regulatory agencies overseeing plugging activity.
 
Some old wells have been located that leak oil or saltwater into the environment — farmland, forests or into nearby streams. They may have never been plugged at all, or only shabbily using tree stumps, rock, clay or other materials. Stay away from wells plugged with a tree stump!
 
Operating in old producing fields can also be expensive or dangerous. There could be communication between wells, including wells that might not even be on a map. You don’t want to see frac fluid erupting from neighboring locations, and not your own well, during completion or stimulation operations!
 
Think about it. The best plugged candidates to re-enter are probably the newest ones, the most recently abandoned. Once the cement plug or plugs are drilled out, the hole and casing can be analyzed. Some kind of mechanical integrity testing may be necessary on the casing in the well. If it’s in good shape, someone might be able to try again to get a producing well. However, there are no guarantees.
 
Re-completions
More second chance wells are re-completed, rather than re-entered after going through the P&A process. Again, any well can be re-completed, but there are all kinds of challenges — technical, environmental or economic — and many different ways to accomplish something in the oilfields of America. And yes, failure is always a distinct possibility. Will the well earn more than the cost of getting it up and running?

Normally a re-completion is less expensive to complete than drilling a new well.

 
Many companies target a number of geologic formations right at the start of drilling a new well. Others do so after a well is drilled. After all, a big oil or gas show should be noticed by geologists, drilling crews or company men during initial drilling and logging operations.
 
There’s nothing like a big oil or gas show on location! First, there may or may not be a drilling break. Or crude oil may flow to the surface and into the mud pits. Gas detectors might buzz. Oil may stream from rock samples under a microscope. Or the occurrence of hydrocarbons may only be indicated on digital wireline logs. People should remember these shows, record them, or look for them when they are searching for new wells to re-complete.
 
Who knows how many potential zones have been overlooked or forgotten? Usually new reserves for a re-completion are found in zones located uphole from the main pay. In this case, all the wellhead equipment, tanks, separators, pipelines, etc., are still in place. Once the new formation is perforated and treated, by whatever means, new production can begin using the wellhead equipment already on location.
 
Re-completions can be done in vertical holes or even kicked off to make a lateral well. Sometimes they can be used to implement a secondary waterflood project or some other kind of enhanced production. Normally a re-completion is less expensive to complete than drilling a new well. But not always.
 
In other circumstances, maybe a well was started or never finished, and is just waiting to be completed. Or one may have to be re-opened after sitting idle for a time. There could be a water, sand or paraffin blockage problem. Call in a service rig, swab it, clean it out, and see what happens.
In fact, in just about every case mentioned above, it would be prudent to call in a well servicing or workover crew to see what you have. Preferably a member of the AESC!
 
Sure it is hard work. But aren’t the best things in life worth working for? Good luck in your efforts.