Can Lowering Casing Pressure Increase Oil production on a Pumping Unit Application?
Yes, reducing the head pressure that a pumping well has on the casing may increase the wells fluid production. The amount of oil and water is usually relative to what was being produced before the pull down, but now more fluids are being produced. Wellbore fluids can now flow more freely into the well bore and this pulldown of pressure can create a “drain-point” for the formation. There have been times when the “oil cut” has also increased by pulling down the casing pressure. Typical successful wellhead casing pulldowns are in 30 to 50 psi range. Substantial increases in production are possible when casing pressure pulldowns are in the 20–50 psi range.
Many times field compression has pulled as low as possible and 30 psi of pressure is being maintained on the casing and your surface equipment to handle fluids, run a heater treater if that is needed to help with separation and provide fuel for your pumping unit if it is gas powered. A wellhead compressor sets ahead of your surface equipment and can pull directly on the casing and discharge back into the flow line so that all of your surface equipment still is in operation. Fuel for your pumping unit can now come from the discharge side of the Wellhead compressor with in-line checks to keep gas from backfeeding in well.
Initial test results after just a day or two may be misleading because of oil that is stacked in the casing may be 4-6 barrels or more, so the pulldown may have some high oil production for the first day or two, so a one-week to a two-week test is recommended. Just reducing the casing pressure from 20 psi to below zero can have a dramatic effect on oil production. With little fluid production being made up the casing many types of compressors can be used for this operation. The only usual hookup requirement is to have a check valve between the suction and discharge lines of the compressor and a fluid dump for the compressors fuel gas scrubber to put fluid into. When using high pressure hoses hook-up time is usually less than 30 minutes.
This can be a very simple and efficient way to increase fluid production and many times with the additional fluid being produced brings an increase in gas sales as well.