基于地层性质与环空状态的钻井液流变参数优选

钻井液流变参数优化设计对安全、优质高效钻井有着十分重要的意义，目前国内外还没有系统、科学、定量的优化理论与方法。笔者论述了钻井液流变参数既要适应所钻地层，又要保持良好的环空状态的优选与设计原则。提出了针对不同钻井液体系选择的流变模式，用井壁冲蚀系数、环空岩屑输送比与环空动压系数来表征环空状态的理论，研究建立了基于地层与环空状态的钻井液流变参数优选的理论与方法，为钻井液流变参数定量优选设计及现场优化控制提供了一种新的理论与工艺技术。 

Optimization of Drilling Fluid Rheology Based on Formation Characteristics and Annular State

Optimization of drilling fluid rheology plays an important role in the safe, high quality and efficient drilling. Presently there is no systematic, scientific and quantified optimization theory and method available for drilling fluid rheology optimization. This paper presents an optimization and design principle, that is, the rheology of the drilling fluid should not only be suitable for operation on the formations to be drilled, it should also help maintain the annular space in good state. Different rheological models were presented for different drilling fluid formulations. A theory and a method which stated that optimization of drilling fluid rheology should be based on the formation to be drilled and the state of the annular spaces were established based on the characterization of the state of annular space with three parameters, which are, index of borehole wall erosion, rate of cuttings transportation in annular space and dynamic annular pressure coefficient. The study has provided a new theory and new technology for quantified optimization of drilling fluid rheology and field optimization of drilling fluids.