新型黏弹性表面活性剂（VES）的要求

新型黏弹性表面活性剂（VES）的要求

新配方的VES，可以满足以下工况：
1  常温甚至更低温度下的均相流动性（具备更低环境温度下的应用）；
2  用VES配好的转向酸，在与碳酸钙反应后所释放出的钙离子作为二价阳离子作为黏弹体结点、能够使黏弹体的常温峰值粘度的要求（国内的采油中，要求常温峰值粘度要大于150mPa.s）；
3  用VES配好的转向酸，在与碳酸钙反应后所释放出的钙离子作为二价阳离子作为黏弹体结点，使黏弹体的高温粘度在一定时间内不低于规定粘度；
4   可以满足95度，5%氯化铵为电解质的粘度要求（这个是模拟砂岩储层只有一价阳离子作为黏弹体的结点，所所形成的黏弹体的粘度达到规定粘度）；
5  可以满足一定的缓速要求（现代VES技术要求的缓速，以达到更大面积、更好质量的造孔要求）。

6   可以满足脱硫海水基配制压裂液，满足抗高钙、耐高温、无残渣、自修复、动态可逆等要求。

6  本身具有一定的缓蚀能力（配方中含有能与“金属表面发生化学键作用的基团+长碳链”）。

为满足以上要求，我们针对不同应用场景的需求、提炼这不同需求中的共同点进行系统的工程设计，一体化合成满足这些要求的黏弹性表面活性剂。

    除以上由于金属阳离子（二价阳离子如钙离、镁离子，一价阳离子如钠离子、钾离子）作为阴离子的反离子起到交联作用的黏弹表面活剂以外，还有对于阴离子作为反离子起到交联作用的黏弹性表面活性剂，举例如下：

     在水基CO₂压裂中，高压下CO₂溶于水中形成碳酸，得到氢离子体系，利用叔胺基团在氢离子体系中质子化形成阳离了、再与对应的反应离子调节得到两亲分子适当的曲率，将球状胶束变成棒状胶束，再通过疏水聚集的缠绕、亲水头基通过反应离子桥联，进而得到具有一定粘度（在较高温下）的黏弹体，进行携沙、压裂、封堵。

Requirements for Novel Viscoelastic Surfactants (VES)

The newly formulated VES is designed to meet the following operating conditions:  
1. Homogeneous flowability at room temperature or even lower temperatures (suitable for applications in lower ambient temperature environments).  
2. For the diverting acid prepared with VES, after reacting with calcium carbonate, the released calcium ions act as divalent cations to serve as junction points for the viscoelastic system, achieving the required peak viscosity at room temperature. In domestic oil extraction, the peak viscosity at room temperature is required to exceed 150 mPa·s.  
3. For the diverting acid prepared with VES, after reacting with calcium carbonate, the released calcium ions act as divalent cations to serve as junction points for the viscoelastic system, ensuring that the high-temperature viscosity of the viscoelastic system remains above the specified value for a certain period.  
4. The ability to meet the viscosity requirements at 95°C in an electrolyte system containing 5% ammonium chloride (simulating sandstone reservoirs where only monovalent cations serve as junction points for the viscoelastic system, achieving the specified viscosity).  
5. The ability to meet certain retardation requirements (as required by modern VES technology to achieve larger-area and higher-quality pore formation).  
6. The ability to be used in desulfurized seawater-based fracturing fluids, meeting the requirements of high calcium resistance, high temperature resistance, residue-free properties, self-healing, and dynamic reversibility.  
7. Inherent corrosion inhibition capability (the formulation includes groups capable of forming chemical bonds with metal surfaces, combined with long carbon chains).

To meet the above requirements, we have extracted the commonalities across different application scenarios and conducted systematic engineering design to synthesize a viscoelastic surfactant that integrates all these requirements.

In addition to the viscoelastic surfactants that rely on metal cations (e.g., divalent cations such as calcium and magnesium ions, or monovalent cations such as sodium and potassium ions) as counterions to achieve crosslinking, there are also viscoelastic surfactants that utilize anions as counterions for crosslinking. An example is as follows:  

In water-based CO₂ fracturing, under high pressure, CO₂ dissolves in water to form carbonic acid, generating a hydrogen ion system. Tertiary amine groups in the system are protonated in the hydrogen ion system to form cations, which, together with the corresponding counterions, adjust the curvature of the amphiphilic molecules. This transforms spherical micelles into rod-shaped micelles. Through the entanglement of hydrophobic aggregates and the bridging of hydrophilic head groups via counterions, a viscoelastic system with a certain viscosity (even at relatively high temperatures) is formed, enabling sand transport, fracturing, and plugging.

以下为*新流变图谱：

一   检测方法

1、基液配制，具体配方如下（按质量加入）：20% CaCl₂+8%转向剂 + 1.8%缓蚀剂+1%铁离子稳定剂+4%增效剂：

2、流变性能测试

将残酸洗液转移到流变仪中，将温度从25℃提高到160℃温度，升温温度梯度为3℃/min，剪切速率为100s^-1。升温至160度后，保持温度2个小时，整个测试共计时间大约160分钟。