EFFECTS OF WETTABILITY AND SALINITY ON MICROBIAL ENHANCED OIL RECOVERY WITH RHODOCOCCUS SP.094

摘要

An extensive experimental program consisting mainly of a large number of coreflooding experiments,but also of measurements of fluid properties,interfacial tension and contact angles was carried out to test the effect of wettability and salinity on Microbial Enhanced Oil Recovery(MEOR).14 water wet and 15 mixed wet bacterial flooding after waterflooding to SorWF were carried out,showing the importance of the distribution of the residual oil.Water wet cores would leave a residual oil saturation after waterflooding of 29% vs.17,5% for the mixed wet cores,and despite this difference the recoveries from bacterial flooding,based on OOIP were the same for both wettabilities,and 4% higher for the mixed wet cases when recoveries were based on the residual oil saturation after waterflooding.7 coreflooding experiments were carried out to test the effect of salinity on MEOR.From these experiments it seems that it is possible to further enhance MEOR performance by reducing salinity,but more importantly,that it is possible to control bacterial growth rate by increasing and decreasing salinity.These experiments together with previous work by the authors,such as tests on micromodels,have allowed to further understand how Rhodococcus sp.094 enhances oil recovery,and an update of the proposed mechanism has been made.