Tertiary Matrix liberation of bypassed Hydrocarbons in Core Sample Pore Throat Restriction caused by fine Particle accumulation after Waterflooding

Abstract

Hydrocarbon’s reservoir management is important, to maximize its deliveries. An important reservoir managerial approach is pressure maintenance, of which water waterflooding is significant, because of its universal availability and avoidability. Despite the numerous advantages of waterflooding, its capability to mobilize, suspend, transport, and redeposit fine sand particles near a producing wellbore is problematic. This problem often led to pressure losses, thereby causing production losses. To solve this problem, core samples with a dimension of 0.12 ft by 0.25 ft made from silicate sand grain of 215-micron aggregates were bonded with Portland cement, at a ratio of 75% to 25%, to represent a formation core. The core samples were oven-dried to remove gaseous and other suspended particles, then, respectively saturated with 1.08 cp brine and 58.02 cp crude oil. The samples were serially loaded into a core holder for flooding. The result showed that, after waterflooding of core samples, A, B, C, and D under laboratory conditions, the residual oil saturations, Sor1, were respectively 39.94%, 39.61%, 32.49%, and 31.52%. These percentages showed that significant amounts of hydrocarbons were still trapped in the core samples after waterflooding. Efforts to recover more of Sor1 lead to the use of chemical flooding, a member of enhanced oil recovery. Bottles that were labeled samples A, B, C, and D contained different blends of mud acids with different concentrations. At the end of chemical flooding; the solution blend in bottle samples A, B, C, and D respectively recovered 41.462, 44.408, 35.242, and 39.499 from Sor1.