Surfactant Flooding Performance for a Canadian Bitumen Recovery:Effectof Polarity

摘要

The objective of this study is to examine the impact of polarity on surfactant-steam flooding performancein the recovery of a Canadian bitumen sample.10 laboratory-scale core flood experiments were used to investigate the interaction between the polar headof surfactants and polar fractions of the bitumen sample(resins and asphaltenes)in the presence of steam.A Canadian bitumen from Alberta with high polar fraction content;resins(17 wt%)and asphaltenes(29 wt%),was selected.The bitumen sample was first characterized in terms of viscosity at reservoir temperature(10,000 cP)and API Gravity(12°).Then,coreflood tests were conducted by coinjecting steam with ananionic,a cationic,or a nonionic surfactant.The performance of three anionic,three cationic,and threenonionic surfactants was tested.Each core flood result was evaluated in terms of the cumulative oil recovery,the residual oil content,the produced oil quality,and the asphaltenes content of produced and residual oilsamples.Then,bitumen's polar fractions(resins and asphaltenes)and bitumen itself were subjected to eachsurfactant solution under steam and liquid water conditions,and simultaneously their interactions werecaptured by an optical microscope.Analysis of microscopic images was used to explain the performancedifferences in each flooding test.Every surfactant-steam flooding process resulted in higher recovery than steam flooding alone.Thegreatest oil recovery was observed with the longest tail length anionic surfactant.It has been observed thatthe presence of asphaltenes in displaced oil inhibits the formation of microemulsions and consequentlyreduces the amount of produced oil.Further,we observed that the microemulsions are successfully formedbetween the resins fraction of bitumen sample and surfactant solution under steam condition.Hence,to maximize the effectiveness of surfactant processes in high asphaltenes content reservoirs,we highlyrecommend the use of asphaltenes precipitants prior to injection of any surfactant solutions.