Experimental Studies On Enhanced Oil Recovery By Low Salinity Water Flooding

Low salinity water is an emerging EOR technology that has gained immense attention among researchers,due to its ease of use,lower cost,and environmentally friendly nature.It has been observed that the injection of dilute brine can increase oil recovery as compared to high salinity water injection.The effect of variables that impact displacement mechanisms have been the subject of research interest for several decades.Low salinity water flooding(LSWF)is an emerging EOR technology in which the salinity of the injected water is optimized to improve oil recovery over conventional water flooding.This study,the attempt is made to cover all aspects and features of LSWF and clear the gaps and deficiencies of conducted studiesTo achieve the above objectives,sandstone cores flooding experiments were conducted to investigate LSW in cores to find the optimum salinity,low salinity effect in both secondary and tertiary mode,and underlying mechanisms during LSW by performing the contact angle measurement and micro-model functionalized.In the secondary mode,low salinity was injected and compared with high salinity injection results.In a tertiary mode,the core was first flooded with high salinity until no more oil was observed or reaching high water cut then,followed by LSW,ion concentration,pH and pressure drop was measured during the flooding.For the mechanisms;the sessile drop method was used to check wettability alteration via contact angle measurement,and micro-model functionalized with active clay minerals as a model system to study the effect of cation exchange during low salinity floodingThe results from the experiments show that LSW has a potential for improving oil recovery in both secondary and tertiary mode for these sandstone rocks.Results also show that wettability alteration is one of the main mechanisms responsible for the improving oil recovery by low salinity technology in a sandstone formation.When low salinity water was injected into the core with high clay contents,the wettability was altering to more water-wet and the oil was produced over a short period of time than during the water flooding with high salinity.This effect of wettability is found to be a function of rock mineralogy,temperature,and brine salinity.Moreover,the divalent ions have more positive effect comparing to monovalentions.