Hi Alex, Thanks for your time today!
1-Can you tell our readers about your company and its background? 2-Regarding SWD wells, what should operators take into account?
M and M Pump and Supply consists of three companies: 1. M and M Pump and Supply Inc., Clay City and Mattoon, Illinois, which sells tubular pipe and sucker rods for oilfields, steel and fiberglass tanks, pumps for downhole oilfield, centrifugal and positive displacement pumps, pipes, valves and fittings and just about anything used to drill, complete or equip an oil or gas well. We also service and repair natural gas engines, seawater pumps, and have a complete inventory of fiberglass pipe and fittings for seawater injection lines. 2. PD Service Co., Clay City, Illinois, providing oil field trucking, oil field construction crews, tank trucks, pipe and casing inspection and testing crews, frac and swab tank rentals, steamers and oilfield tapping services. 3. McCoy Machine and Gear Co., Flora, Illinois, providing a complete oilfield machine shop, new and rebuilt pump units, and mobile service trucks for field repair of pump units and saltwater pumps and manufacture of Miller sand pumps.
With regards to salt water disposal and injection wells, I would recommend running a good chain of Sealtite or CPVC plastic lined pipe to protect against internal corrosion and make sure you protect the annular space between the casing and the outside of the pipe with a good corrosion inhibitor. , oxygen scavenger and biocide in liquid or granule form. If you are waterflooding, be sure to choose a good producer for your injection well, as these seem to make the best injection wells with the best waterflooding results. It goes without saying that a petroleum engineer will analyze your field for recoverable barrels of oil and desired injection rates per injection well to improve your chances of getting the best results from your waterflooding. Establish a good chemical program for your injected water to control corrosion and scaling tendencies. Beginning this program immediately is vital to minimizing problems down the road that could lead to excessive withdrawal from producing and injector wells in a flood. Have your injected and produced water tested for compatibility by a chemical company to prevent possible severe scaling and corrosion in the future.
3-What type of pumps work best for SWD wells? How do they work?
Everything about selecting pumps for a salt water injection or disposal well is defined by barrels per day of water to be injected and the maximum pressure required to inject the water at that rate. Since most injection wells require moderate injection pressures (300 to 700 PSI) to very high pressures (over 2000 PSI), a positive displacement pump such as a plunger or piston pump or a diaphragm pump. All positive displacement pumps require a good supply of water at the pump inlet and it is very important to ensure this is achieved by oversizing and flooding the pump suction or by charging the pump suction with a properly sized centrifugal pump. . Pumps of this type are usually powered by an electric motor or gasoline engine with adequate power to handle the maximum flow rate and pressures the pump will be subjected to. The braking power requirement is calculated using the following formula: gallons per minute times the maximum pressure times a constant of 0.000648 equals the maximum braking power required.
4-I have heard a lot about Hydra-Cell and Cat pumps, are there other brands to consider?
Some of the most common brands of positive displacement pumps are Gaso, Wheatley, Oilwell, Gardner Denver, Bethlehem (B-Master), Kerr, Myers, Union, Ingersoll Rand, Cat, Hydracell, among others. The key to choosing which pump works best for your application once again depends on the barrels per day to be injected and the pressure required to achieve it. Another key consideration would be to have a dealer stock parts and services for the brand of pump you are purchasing so that downtime for pump service and repairs can be kept to a minimum. Hydracell pumps are in most cases less expensive than plunger pumps if you can find one that meets your volume and pressure requirements. These pumps will also likely require complete replacement after 5 to 10 years of service. Large plunger pumps such as Gaso, Wheatley, Oilwell, Gardner Denver, Kerr, B-Master can run for 40-50 years if properly maintained and rebuilt every 3-10 years depending on service conditions.
Cat pumps fill the niche for very high pressure, low volume applications particularly well at a reasonable cost, but replacement parts costs tend to be quite high when the pump needs service. Probably the most important thing you can do for any of the above pumps is to develop a good preventative maintenance schedule, paying particular attention to the condition of the oil at the power end of the pump. Pumps in this service frequently run 20 hours a day or more, making it imperative that a daily preventative maintenance inspection is performed and fluid change intervals are strictly followed.
5-Do some brands have pros and cons?
6-Any precaution for maintenance or continuous use that should be taken with this type of pump?
#5 and #6- I partially answered these questions by answering question #4. Other maintenance considerations. Be sure to purchase a gland wrench for tightening the plunger packing on plunger pumps, as well as a valve cover hammer wrench for pumps with threaded valve covers. Some pumps use a deep gland gland wrench and others require a spanner. In addition to the daily inspection of the power end gear oil, the plunger packing should be tightened if the plungers are leaking more than 3 to 5 drops per plunger per minute; however, it is imperative not to overtighten the plunger packing like ceramic plungers typically used in saltwater service. it will rupture if subjected to heat over 150°F and this can occur if the gasket is over-tightened. It is generally best to let plungers run for several minutes after tightening the packing, turn off the pump, then feel the ceramic part of the plunger and make sure it is not hot to the touch; if so, the packing is probably too tight.
If you have a vacuum-operated injection well and want to suck your tanks dry, install a check valve with a heavy spring that won’t allow the well to suck your tanks. This will prevent breakage of the plunger as the pump is air powered and sucks any BS above the water into the pump valves. I would also recommend installing a Y-strainer in the inlet line to the pump to prevent debris from clogging the valves on the pumps. Be sure to inspect this filter regularly and after the initial hour of pump operation and after 24 hours of initial operation, as there is likely debris in the newly assembled lines that could clog the filter. When running the Hydracell pumps check the gear oil daily as if you poke a hole in one of the diaphragms the salt water will have direct access to the power end of the pumps. Finally, be sure to oversize the pump inlet (suction) line and use as few 90 degree angles as possible to ensure adequate fluid supply to the pump. Remember the old adage that 6-90 degrees els almost equals a bull plug!
7-Should an operator overcompensate and buy a pump that has a much higher horsepower than indicated?
A certain amount of safety factor must be incorporated into the design of all pumps and motors in the event injection volumes exceed original estimates or more pressure is required to dispose of the injected water than originally estimated. It is also advisable not to run any pump at the maximum recommended RPM, as this will result in higher maintenance and rebuild costs than a pump running at 80-85% of its maximum capacity. I would recommend designing your pump system to 75-80% of the volume and pressure capabilities of a pump. This will allow for a little extra volume and pressure if needed without causing maintenance headaches down the road.
8-What is a common problem that you see in the field?
Common problems I see in the field are: A. Failure to properly maintain power unit oil quality leads to costly power unit repairs. B. Do not oversize pump suction lines and allow adequate water supply to pump inlet valves, leading to premature valve failure. C. Failure to install a bypass valve in the pump discharge lines, leading to catastrophic failure, such as a broken pump crankshaft, if someone forgets and starts the pump against a closed valve. D. Not filtering incoming water to the pump and not regularly inspecting the mesh on suction Y-screens, particularly when water is transported to the lease by tanker (Note: a settling tank is best used when transporting water to the lease by tanker trucks.) E. Failing to install a bleed valve in the pump discharge line to allow trapped air to bleed out of the pump. Failure to comply with a daily and weekly inspection and maintenance schedule for the pump.
9-Please tell our readers how to handle corrosive fluids in the pump.
To properly prevent corrosion in a seawater pump, the fluid end of the pump should generally be aluminum bronze or 316 stainless steel, which are highly resistant to corrosion. In some brines that are not too corrosive and where pressures are not too high, a bronze fluid end will give satisfactory service at a significantly cheaper price than aluminum bronze or stainless steel. However, standard brass has limited resistance to hydrogen sulfide and will often wash out quickly when handling brines containing H2S. It is also a good idea to chemically treat the injected water for both corrosion and scaling tendencies, as this will prevent the injection well from clogging and protect the downhole tubes.