In the world of oil and natural gas extraction, setting up new drill sites on areas of land that have produced consistently high quantities of oil in the past is an innovative and low-risk way to ensure quality oil production. Sentry Energy Production LLC, a privately held oil and natural gas company based in Addison, Texas, draws upon this very method throughout all aspects of its operations. In addition to located new pay zones in productive areas, Sentry Energy Production also applies some of the latest advances in technology to extract additional oil from existing wells.
Like many oil companies, Sentry Energy Production makes heavy use of the pumpjack, one of the most ubiquitous pieces of oil drilling equipment in the history of the industry. Commonly referred to as a horsehead pump or a beam pump, the pumpjack utilizes reciprocating piston pump to extract oil from an oil well. In general, pumpjacks are most effective when used on land in areas that produce little oil with bottom hole pressure alone. Pumpjacks also have the potential to vary greatly in size, ranging from 5 to 40 liters of oil production during each pump cycle, based on the depth and weight of the oil in question. In most cases, pumpjacks rely on energy from a rotational motor to produce the vertical reciprocating motion necessary to extract oil.
Before the development of sophisticated electric motors, pumpjacks often relied on a network of rod lines that were connected to a wheel mechanism known as a Central Power. The Central Power system was highly inefficient, however, as it relied on combustion engines and required a high level of maintenance to operate at maximum production levels. Today, pumpjacks derive the majority of their energy from a device known as a prime mover. Although most prime movers currently take the form of an electric motor, many make use of unorthodox engine types such as propane systems and casing gas from the well itself. Deep in the well hole, pumpjacks contain a feature called a down-hole pump, composed of two ball check valves. As the pump descends into the well, oil enters the formation through a series of perforations in the casing and cement. As the pump lifts out of the well, the traveling valve closes, allowing the formation to safely transport the oil to the surface before depositing it in the pump barrel.