Emami Hassan, Ayatizadeh Tanha Abbas, Khaksar Manshad Abbas, Mohammadi Amir H
Institute of Petroleum Engineering, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran 1417614411, Iran.
Department of Well Logging, National Iranian Drilling Company, Ahwaz 90161635, Iran.
ACS Omega. 2022 Apr 19;7(17):14832-14847. doi: 10.1021/acsomega.2c00314. eCollection 2022 May 3.
Gravity override and viscous fingering are inevitable in gas flooding for improving hydrocarbon production from petroleum reservoirs. Foam is used to regulate gas mobility and consequently improve sweep efficiency. In the enhanced oil recovery process, when the foam is introduced into the reservoir and exposed to the initial saline water saturation and pH condition, selection of the stable foam is crucial. Salinity and pH tolerance of generated foams are a unique concern in high salinity and pH variable reservoirs. NaOH and HCl are used for adjusting the pH, and NaCl and CaCl are utilized to change salinity. Through analyzing these two factors along with surfactant concentration, we have instituted a screening scenario to optimize the effects of salinity, pH, surfactant type, and concentration to generate the most stable state of the generated foams. An anionic (sodium dodecyl sulfate) and a nonionic (lauric alcohol ethoxylate-7) surfactants were utilized to investigate the effects of the surfactant type. The results were applied in a 40 cm synthetic porous media fully saturated with distilled water to illustrate their effects on water recovery at ambient conditions. This most stable foam along with eight different stabilities and foamabilities and air alone was injected into the sand pack. The results show that in optimum surfactant concentration, the stability of LA-7 was not highly changed with salinity alteration. Also, we probed that serious effects on foam stability are due to divalent salt and CaCl. Finally, we found the most water recovery that was obtained by the three most stable foams by the formula of 1 cmc SDS + 0.5 M NaCl, 1 cmc SDS + 0.01 M CaCl, and LA-7@ pH ∼ 6 from porous media flooding. Total water recovery for the most stable foam increased by an amount of 65% compared to the state of air alone. A good correlation between foam stability and foamability at higher foam stabilities was observed.
在气驱提高油藏烃类产量的过程中，重力超覆和粘性指进是不可避免的。泡沫被用于调节气体流度，从而提高波及效率。在强化采油过程中，当泡沫被注入油藏并暴露于初始盐水饱和度和pH条件下时，选择稳定的泡沫至关重要。在高盐度和pH值可变的油藏中，生成泡沫的盐度和pH耐受性是一个独特的问题。NaOH和HCl用于调节pH值，NaCl和CaCl用于改变盐度。通过分析这两个因素以及表面活性剂浓度，我们制定了一个筛选方案，以优化盐度、pH值、表面活性剂类型和浓度的影响，从而使生成的泡沫达到最稳定状态。使用一种阴离子表面活性剂（十二烷基硫酸钠）和一种非离子表面活性剂（月桂醇聚醚-7）来研究表面活性剂类型的影响。将结果应用于一个40厘米长、完全饱和蒸馏水的合成多孔介质中，以说明它们在环境条件下对水采收率的影响。将这种最稳定的泡沫以及八种不同稳定性和发泡性的泡沫和单独的空气注入砂柱中。结果表明，在最佳表面活性剂浓度下，LA-7的稳定性不会随盐度变化而发生很大改变。此外，我们还探究到二价盐和CaCl对泡沫稳定性有严重影响。最后，我们通过1 cmc SDS + 0.5 M NaCl、1 cmc SDS + 0.01 M CaCl和pH约为6的LA-7配方，从多孔介质驱替中找到了三种最稳定泡沫实现的最高水采收率。与单独空气状态相比，最稳定泡沫的总水采收率提高了65%。在较高泡沫稳定性下，观察到泡沫稳定性与发泡性之间具有良好的相关性。
