Surfactants formulated into oil-based mud can adsorb to pore surfaces causing changes in rock wettability, which are widely believed to impair formation permeability when oil-based mud invades the near-wellbore region. In the present study, the effects of oil-based mud with Versawet and Versacoat surfactants, on the petrophysical properties and wettability of drilling cutting samples from sandstone reservoirs were investigated through relative permeability, wettability index, and adsorption measurements at standard conditions in a micromodel device. The X-ray analysis and flame photometer were used to characterize the drilling cuttings samples, and the functional groups of surfactants were identified by the infrared spectroscopy. Relative permeability was studied using the unsteady state method, and the wettability index was measured by the Amott method after the aging with drilling formulation for 24 to 720 h and then the adsorption behavior of surfactants using Langmuir isotherm. The results show that drilling cutting is mainly composed of quartz 71.9%. Surfactant in oil-based mud reduces permeability and causes a change in wettability to a more oil-wet state, and these effects become more pronounced as the contact period with the surfactant increases. The wettability of a reservoir rock was altered due to surfactant adsorption and the formation of a hydrophobic layer on the surface of drilling cutting samples. The adsorption and retention of polar part of the surfactants -NH₂ for Versawet and -COOH for Versacoat on the silanol groups and the calcium atoms included in the structure of the reservoir rocks. They are the key interactions in the wettability alteration process.

配制到油基泥浆中的表面活性剂可以吸附到孔隙表面，导致岩石润湿性发生变化，人们普遍认为，当油基泥浆侵入近井眼区域时，这会损害地层渗透率。在本研究中，通过微模型装置在标准条件下的相对渗透率、润湿性指数和吸附测量，研究了含 Versawet 和 Versacoat 表面活性剂的油基泥浆对砂岩储层钻屑样品的岩石物理性质和润湿性的影响. 采用X射线分析仪和火焰光度计对钻屑样品进行表征，通过红外光谱对表面活性剂的官能团进行鉴定。使用非稳态方法研究相对渗透率，润湿性指数是在钻井液老化24~720 h后用Amott法测定，然后用Langmuir等温线测定表面活性剂的吸附行为。结果表明，钻屑主要成分为石英71.9%。油基泥浆中的表面活性剂会降低渗透率，导致润湿性变为更亲油的状态，随着与表面活性剂接触时间的增加，这些影响变得更加明显。由于表面活性剂的吸附和钻井切削样品表面疏水层的形成，储层岩石的润湿性发生了变化。表面活性剂极性部分-NH的吸附和保留 结果表明，钻屑主要成分为石英71.9%。油基泥浆中的表面活性剂会降低渗透率，导致润湿性变为更亲油的状态，随着与表面活性剂接触时间的增加，这些影响变得更加明显。由于表面活性剂的吸附和钻井切削样品表面疏水层的形成，储层岩石的润湿性发生了变化。表面活性剂极性部分-NH的吸附和保留 结果表明，钻屑主要成分为石英71.9%。油基泥浆中的表面活性剂会降低渗透率，导致润湿性变为更亲油的状态，随着与表面活性剂接触时间的增加，这些影响变得更加明显。由于表面活性剂的吸附和钻井切削样品表面疏水层的形成，储层岩石的润湿性发生了变化。表面活性剂极性部分-NH的吸附和保留 由于表面活性剂的吸附和钻井切削样品表面疏水层的形成，储层岩石的润湿性发生了变化。表面活性剂极性部分-NH的吸附和保留 由于表面活性剂的吸附和钻井切削样品表面疏水层的形成，储层岩石的润湿性发生了变化。表面活性剂极性部分-NH的吸附和保留₂用于 Versawet 和 -COOH 用于 Versacoat 硅醇基团和包含在储层岩石结构中的钙原子。它们是润湿性改变过程中的关键相互作用。