If the oil at Cymric is heavy, how can it be encouraged to flow to the surface through the wellbore? An increase in temperature reduces the viscosity of any oil. At Cymric, engineers have developed an enhanced oil recovery method called cyclic steam to enhance production (see the figure to understand this process). This combination of injecting water and heat assists the movement of oil toward production wells. The wells in the Cymric field operate at ~1,000-1,500 ft vertical depth and are often closely spaced, with some parts of the oil field having wells spaced only 110 ft apart.1Cymric Oil Field. (20201, February 8). In Wikipedia. https://en.wikipedia.org/wiki/Cymric_Oil_Field
Cyclic steam stimulation of a reservoir is sometimes applied to heavy-oil reservoirs to boost recovery during the primary production phase. The idea is to assist the natural reservoir energy by thinning the oil so it will more easily move through the rock formation to the surface. The cyclic steam process uses a single well for both injection and production. A predetermined amount of steam is injected into the well (‘huff’). The well is then shut in (closed to production) to allow the steam to heat or ‘soak’ the formation and fluids around the well. After a sufficient time has elapsed to allow adequate heating, the well is put back on production (‘puff’) until the production rate sufficiently declines to indicate the heated fluid has mostly been produced. This cycle of soak-and-produce, or “huff-and-puff,” is repeated until the response becomes marginal due to various reservoir factors, making the well no longer profitable.2Steam injection (oil industry). (2020, November 26). In Wikipedia. https://en.wikipedia.org/wiki/Steam_injection_(oil_industry)