Understanding the Hidden Fluid Property of Elasticity, Viscosities Influential Cousin

在钻长水平威尔斯井时，钻井液中的固体颗粒会在井底形成固定床，造成钻井作业困难，如扭矩和阻力过大，钻井速度慢，严重时会造成卡钻、井漏甚至井控失控。有时，钻井必须停止以清洁固定床，这是一个昂贵的过程，必须及时完成。了解钻井液流变特性如何影响颗粒从床沉积物中的去除是开发有效井眼清洁的最佳水力学程序的关键。大多数用于水平威尔斯井钻井的钻井液都是粘弹性的。 以往的室内试验和现场经验表明，流体的弹性特性对携岩能力有重要影响，应与流体的粘性特性一起考虑，以便更真实地评价钻井液的携岩能力。 目前还没有实际的方法来测量和量化现场钻井液的弹性。因此，提出了一项实验研究来填补这一知识空白。本研究的主要目标是：i-）开发一个现场适用的模型，可用于量化弹性，通过使用工业标准流变仪的测量; ii-）开发一种方法，以提供实验室到现场规模的分析之间的联系，因此，以促进直接应用的实验结果在开发模型的现场应用。在过去的几十年中，水平威尔斯钻井的数量急剧增加，然而，井眼清洁仍然是一个挑战，特别是在钻长水平段时。需要开发有效的井眼清洁策略以减少与井清洁相关的时间。清孔时间越短，实际钻孔所花费的时间就越多，因此，可以显著降低钻孔成本。以较低的成本交付油井对于确保储量的可获得性至关重要，否则开采这些储量在经济上是不合理的。工业的安全和经济运行的能力将极大地受益于一个全面的实验研究，如在这项研究中提出的。

When drilling long horizontal wells, drilled solids tend to settle down on the low side of the wellbore and form a stationary bed, which causes operational difficulties such as excessive torque and drag, slow drilling rate, and in severe cases, stuck pipe, lost circulation, and even loss of the well control. Occasionally, drilling must stop to clean the stationary bed, which is an expensive process and must be done in a timely manner. Understanding how the drilling fluid rheological characteristics affect particle removal from bed deposits is a key to the development of optimum hydraulics program for effective hole cleaning. Most of the fluids used for drilling horizontal wells are of viscoelastic nature. Previous laboratory tests and field experience indicate that fluid elastic properties play important role in cuttings transport and should be given due consideration together with fluid viscous properties in order to have more realistic assessment of the cuttings transport ability of a drilling fluid. Currently there is no practical way to measure and quantify the elasticity of a drilling fluid in the field. An experimental study is, therefore, proposed to fill up this knowledge gap. The main objectives of this study are: i-) to develop a field applicable model that can be used to quantify elasticity by using the measurements from industry standard rheometer; ii-) to develop a methodology to provide the link between lab to field scale analyses and, hence, to facilitate direct application of the experimental results in the development of models for field applications. The number of horizontal wells drilled has dramatically increased over the past decades, however, hole cleaning still remains a challenge especially when drilling long horizontal sections. Efficient hole cleaning strategies need to be developed to reduce time associated with well cleaning. The shorter the hole cleaning time, the more time can be spent on actual drilling and, as a result, the drilling cost can be reduced significantly. Delivering an oil well at lower costs is essential in ensuring accessibility of reserves, which otherwise are not economically sound to exploit. Industry's capacity to operate safely and economically will benefit tremendously from a full-scale experimental research such as the one proposed in this study.