基于漂移流动模型的水平井岩屑床高度瞬态计算新方法  

A new transient calculation method of cuttings bed thickness based on drift flow model

作　　者：孙晓峰 姚笛[1] 孙士慧 纪国栋 于福锐 孙铭浩 赵元喆 陶亮 SUN Xiaofeng;YAO Di;SUN Shihui;JI Guodong;YU Furui;SUN Minghao;ZHAO Yuanzhe;TAO Liang(Key Laboratory of Enhanced Oil and Gas Recovery of Ministry of Education//Northeast Petroleum University,Daqing,Heilongjiang 163318,China;Sanya Offshore Oil&.Gas Research Institute,Northeast Petroleum University,Sanya,Hainan 572025,China;CNPC Engineering Technology R&D Company Limited,Beijing,102206,China)

机构地区：[1]“提高油气采收率”教育部重点实验室·东北石油大学,黑龙江省163318 [2]东北石油大学三亚海洋油气研究院 [3]中国石油集团工程技术研究院有限公司

出　　处：《天然气工业》2022年第5期85-92,共8页Natural Gas Industry

基　　金：国家自然科学基金面上项目“基于环空固液两相瞬态流动特性研究页岩气水平井卡钻事故的诱发机制”(编号:52174002);国家自然科学基金青年科学基金项目“页岩气藏CO_(2)干法压裂相态控制机理研究”(编号:52004064)。

摘　　要：水平井已成为常规和非常规油气资源开采的常用井型,但水平井钻井过程中造斜段与水平段环空极易堆积形成岩屑床,为避免岩屑床沉积所导致的埋钻、卡钻事故,需要对环空中的岩屑床高度进行实时准确预测。为此,基于漂移流动模型建立了环空固液两相瞬态运移模型,应用基于交错网格的有限体积法对环空进行离散化,并采用投影方法进行数值求解。研究结果表明:①投影方法可以应用于环空固液两相流瞬态计算当中,且求解效率高于传统的压力—速度耦合算法;②岩屑进入环空后,首先在钻头处形成稳定岩屑床并逐渐向出口方向延伸,由于岩屑运移所产生的阻力远高于钻井液流动阻力,岩屑体积分数较高的井段环空压耗大幅增加;③环空中形成稳定岩屑床的时间主要受排量影响,低环空排量形成稳定岩屑床的时间较高环空排量所需时间更长;④通过与稳态岩屑床高度模型进行对比,所建立模型可满足实钻过程中的工程需要,且准确性可靠。结论认为,建立的模型用于预测大斜度井段岩屑床瞬态高度,计算效率较高,能够为水平井岩屑床高效清除与卡钻事故风险预测提供一定的理论指导。Horizontal wells have already been a common well type for the production of conventional and unconventional oil and gas resources, but in the drilling process, cuttings accumulate to form cuttings bed easily in the annulus of deflection sections and horizontal sections. In order to avoid pipe burying and sticking accidents caused by the deposition of cuttings bed, it is necessary to accurately predict the thickness of the cuttings bed in the annulus in real time. In this paper, a transient migration model of solid-liquid two-phase flow in the annulus is established based on the drift flow model, and the annulus is discretized by using the finite volume method based on staggered grids, and it is numerically solved by means of projection. And the following research results are obtained. First, the projection method can be applied to the transient calculation of solid-liquid two-phase flow in the annulus, and its solution efficiency is higher than that of traditional pressure-velocity coupling algorithm. Second, after the cuttings flow into the annulus, a stable cuttings bed is firstly formed at the bit and then gradually extends to the outlet. Since the resistance generated by cuttings migration is much higher than the flow resistance of drilling fluid, the annulus pressure loss in the well section with higher cuttings volume fraction increases significantly.Third, the time to form a stable cuttings bed in the annulus is mainly affected by the displacement, and the time to form a stable cuttings bed at a low annular displacement is longer than that at a higher annular displacement. Fourth, it is verified by comparing with the steady-state cuttings bed thickness model that this new model is accurate and reliable enough to meet the engineering needs in the process of actual drilling. In conclusion, the proposed model has high calculation efficiency and can be used to predict the transient thickness of cuttings bed in highly deviated well sections. The research results can provide a certain theoretical guidance for th

关 键 词：固液两相流动 水平井 岩屑床高度 岩屑运移 投影方法 漂移流动模型 不可压缩流动 

分 类 号：TE28[石油与天然气工程—油气井工程]