Enhanced Oil Recovery by using Polymer Flooding in Oil and Gas Industry in Tertiary Recovery Process

Abstract

In very early days of the oil industry, the general practice in land-based shallow reservoirs was to produce oil by primary depletion. In this method, the compression al energy of the reservoir was used to force oil to the producer wells, with a consequent drop in the reservoir pressure. However, it was recognized that reservoirs would ultimately drop below bubble point pressure, such that dissolved gas would be released from the oil. As a result of the appearance of this extra phase, production impairment would occur. In order to maintain reservoir pressure and also to sweep out oil in a more efficient displacement process, water flooding became the standard practice in many reservoir formations and still finds a wide application. When water is injected under pressure, it would seek the path of least resistance to point of lowest pressure, which is generally producing well. If the mobility ratio is one or less, the displacement of oil by water is found to be efficient. In effect, the displacement occurs in a piston like fashion. On the other hand if mobility ratio is greater than one, the more mobile water fingers through the oil leaving it in place in the reservoir.