The evaluation of dodecyl hydroxy sulfobetaine as a high-temperature and high-salinity resistant foaming agent in sandstone reservoirs

AbstractFor the high temperature (130 °C), high pressure (30 MPa), and high salinity (2.5 × 105 mg/L) of formation water conditions in the target block of the Tarim Basin Oilfield in northwest China, dodecyl hydroxy sulfobetaine surfactant was evaluated for its foaming performance, thermal stability, adsorption performance. The evaluation results showed that the surfactant exhibited good foaming ability and thermal stability than the general carboxy betaine under the above harsh conditions. The static adsorption of the surfactant on the surface of quartz sand particles was less than 1 mg/g with a concentration of less than 0.4%, which met the requirement for foaming agent adsorption. Moreover, the results of core displacement experiments indicated that, when simultaneously injecting 0.4% foaming agent and gas at a volume ratio of 3:7 into the cores of 38 mD, 161.4 mD, and 478.7 mD, foam with low mobility of less than 2 mD/cP could be generated; in the 57.3 mD Berea core, the resistance factor of foam generated by 8 cycles of injecting gas-liquid alternately with gas-liquid volume ratio ranging from 0.2:0.1 to 0.4:0.1 was nearly 20, and the residual resistance factor was greater than 5 after 5 PV of continuous gas injection. The results of the study can guide the selection of foaming agents for gas mobility control in high-temperature and high-salinity sandstone reservoirs.Keywords: Foameramphoteric surfactanthigh-temperature and high-salinitysandstone reservoirsgas injection Declaration of interest statementWe confirm that neither the manuscript nor any parts of its content are currently under consideration or published in another journal. No conflict of interest exists in the submission of this manuscript, and all authors have approved the manuscript and agree with its submission to "Journal of Dispersion Science and Technology".Additional informationFundingFinancial support by the Major Scientific and Technological Projects of CNPC under Grant ZD2019-183-007 is gratefully acknowledged.