Thermal Recovery of Niger Delta Heavy Crude

Unconventional oil reserve estimate in Nigeria which is at an average of 42 billion barrels of hydrocarbon deposits, surpasses the proven reserve of 37.2 billion barrels of conventional oil reservoirs. With these statistics, the need to evaluate the prospects of production from these unconventional reservoir systems becomes a subject of interest. In this study, a thermal approach towards the recovery of a Niger Delta heavy crude oil was conducted by the viscosity reduction mechanism via hot water injection. Fluid characterization via laboratory tests revealed that the Niger Delta retrieved heavy crude sample had a viscosity 17.80 cp,13.24oAPI and a density of 0.997.6 g/cc. This sample was subjected to a series of recovery processes with hot water temperature ranging from 75 OC to 100 OC at an interval of 5oC, using a locally constructed apparatus. It was used to simulate a reservoir bulk volume of 30 litres and 8.871 liters pore volume having fluid saturations of 20% formation brine. The heavy crude viscosities were found to be in the magnitude of 1.95cp to 0.87 cp for injected hot water of 75 OC to 100 OC after post recovery tests. Temperature losses to the rock matrix of a heavy crude reservoirs and optimum injection temperatures for a known reservoir bulk volume were also established via experimental processes. The validity of assertion that hot water injection can considerably alter flow properties of heavy oils was experimentally confirmed upon comparing with a convention al water injection process.