Understanding the Hidden Fluid Property of Elasticity, Viscosities Influential Cousin

点击翻译按钮获取中文摘要

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.