Rule based design of clay-swelling inhibitors
Rule based design of clay-swelling inhibitors
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DOI：
10.1039/c1ee01280k
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发表时间：
2011-11-01
影响因子：
32.5
通讯作者：
Cliffe, S.
中科院分区：
文献类型：
--
作者：
Suter, J. L.;Coveney, P. V.;Cliffe, S.
在石油和天然气钻井作业中，钻井液执行基本任务，例如润滑钻头，提供静水压力和去除钻屑。钻井液的一个重要功能是阻止在钻井操作中通常遇到的压实粘土矿物从钻井液中吸收水并因此膨胀。这种情况可能对钻井作业产生不利影响，并可能导致油井建设成本大幅增加。随着越来越严格的环境指南确定哪种膨胀抑制剂可用作油田钻井液添加剂，需要充分了解粘土水合的机制，以便设计符合不断发展的法规的新的膨胀抑制剂。使用一系列的计算技术和分析，结合已知的实验结果，我们已经设计出一套“基于规则”的粘土膨胀抑制剂的设计标准。为了实现这一目标，我们制定了一个水化能参数，它评估了能量的变化，在逐步进行的过程中，从单到双到三层的水在粘土片画廊。该参数可用于合理化和预测的粘土含有阳离子和中性粘土膨胀抑制剂的膨胀曲线。我们设计的规则如下：（i）阳离子抑制剂应该能够取代层间的钠离子。(ii)阳离子抑制剂应具有水溶性的疏水主链。(iii)阳离子抑制剂应具有伯二胺或单季胺官能团。(iv)阳离子抑制剂应具有很少的醇官能度。(v)阳离子抑制剂的疏水主链应足够长以在夹层中形成致密的单层。(vi)对于中性抑制剂，该抑制剂应该是低分子量的水溶性有机分子，其具有良好限定的相对高疏水性域和小疏水性域。我们的“基于规则”的标准将有助于合理设计改进的和更环保的油田钻井作业用粘土膨胀抑制剂。
In oil and gas drilling operations, drilling fluids perform essential tasks such as lubricating the drill bit, providing hydrostatic pressure and removing drill cuttings. One important function of the drilling fluid is to stop compacted clay minerals, commonly encountered in drilling operations, from taking up water from the drilling fluids and consequently swelling. Such a scenario can have an adverse impact on drilling operations and may lead to significantly increased oil well construction costs. With increasingly stringent environmental guidelines determining which swelling inhibitors are available for use in the oilfield as drilling fluid additives, there is a need to fully understand the mechanisms of clay hydration in order to design new swelling inhibitors which conform to evolving regulations. Using a range of computational techniques and analysis, combined with known experimental results, we have devised a set of "rule-based'' design criteria for clay-swelling inhibitors. To achieve this, we have formulated a hydration energy parameter, which assesses the changes in energy during the step-wise progression from mono- to bi- to trilayers of water in the clay sheet galleries. This parameter can be used to rationalise and predict the swelling profiles for clays containing both cationic and neutral clay swelling inhibitors. The rules we have devised are as follows: (i) Cationic inhibitors should be able to replace sodium ions in the interlayer. (ii) Cationic inhibitors should possess a water soluble, hydrophobic backbone. (iii) Cationic inhibitors should have primary di-amine or mono-quaternary amine functionality. (iv) Cationic inhibitors should have little alcohol functionality. (v) The hydrophobic backbone of the cationic inhibitor should be long enough to form a dense monolayer in the interlayer. (vi) For neutral inhibitors, the inhibitor should be a water soluble organic molecule of low molecular weight with well defined domains of relatively high hydrophobicity and small domains of hydrophobicity. Our "rule-based'' criteria will facilitate the rational design of improved-and more environmentally acceptable-clay swelling inhibitors for oilfield drilling operations.