A Study On The Adsorption And Rentention Of Surfactant Used For ASP Flooding On The Reservoir Sand Of Daqing Oil Field

The adsorption laws of surfactants in the different systems on the reservoir sand of Daqing oil field is systematically studied in this paper. The static adsorption experiments are conducted to study the best adsorption parameter at 45℃.The results show their adsorptions are not fit for Langmuir adsorption isothermal model. A maximum is observed when concentration of surfactants is near the range of CMC. At the same surfactant concentration,the larger of molecular weight of the surfactant,the higher of its adsorbance on oil sand. Adsorbance of surfactant is different in different systems. Two kind surfactants samples'maximum adsorbance on oil sand are 1.29mg/g sand and 1.34mg/g sand respectively. The affluence of the conception and type of the alkali for the static adsorption on reservoir sand of Daqing oil field of heavy sulfonates (HABS) is studied. The results show that the adsorption of HABS from different concentration of NaOH aqueous is different. The adsorbing quantity of HABS present to enlarge first, then let up,then enlarge again along with the increment of the NaOH density; and larger from all the tested density Na2CO3 solutions; the adsorption of HABS can be significantly reduced by used mixed alkaline Na3PO4/Na2CO3. Preliminary corngnition is that the alkaline was enhanced.Any concentration of Na3PO4/Na2CO3 solutions can decrease the adsorption of the HABS on reservoir sand of Daqing oil field. Polymer also can decrease the static adsoption of HABS,but the degree is lower. The mechanism of the maximum adsorption of surfactant on oil sand is analyzed. The model of surfactant adsorption on oil sand is established by steps.The dynamic retention of surfactant in ASP system in natural core is studied,the result shoe that:①When the influx displacing agent attain to 1.4PV,the concentration of the surfactant is keep balance,the concentration distribution in the wholly core is counter balance.②the retention of surfactant is 0.094mg/g sand and 0.0048 mg/g sand, which is lower than that of static absorbance,are in accord with the surfactant loss in actual reservoir.③The dynamic retention of surfactant in AS system (NaOH concentration is 0.8~1.0%) in natural core is lower,this means that the NaOH can decrease the adsorption of surfactant; at the same time,the affection of various mixed alkaline for the dynamic retention is accordance the static adsorption.