摘要：Deepwater sediments are prone to loss circulation in drilling due to a low overburden gradient. How to predict the magnitude of leak-off pressure more accurately is an important issue in the protection of drilling safety and the reduction of drilling cost in deep water. Starting from the mechanical properties of a shallow formation and based on the basic theory of rock-soil mechanics, the stress distribution around a borehole was analyzed. It was found that the rock or soil on a borehole is in the plastic yield state before the effective tensile stress is generated, and the effective tangential and vertical stresses increase as the drilling fluid density increases; thus, tensile failure will not occur on the borehole wall. Based on the results of stress calculation, two mechanisms and leak-off pressure prediction models for shallow sediments in deepwater drilling were put forward, and the calculated values of these models were compared with the measured value of shallow leak-off pressure in actual drilling. The results show that the MHPS (minimum horizontal principle stress) model and the FIF (fracturing in formation) model can predict the lower and upper limits of leak-off pressure. The PLC (permeable lost circulation) model can comprehensively analyze the factors influencing permeable leakage and provide a theoretical basis for leak-off prevention and plugging in deepwater drilling.

关键字：deepwater drilling shallow sediments leak-off mechanism leak-off pressure

ISSN号：1672-5182

卷、期、页：卷: 17 期: 1 页: 65-71

发表日期：2018-02-01

期刊分区（SCI为中科院分区）：四区

收录情况：SCIE（科学引文索引网络版）,CSCD（中国科技引文期刊）（核心）,CSTPCD（中国科技核心期刊）（统计源期刊）,ESI（基本科学指标数据库）

发表期刊名称：Journal of Ocean University of China

参与作者：孙金

第一作者：谭强,邓金根,刘伟,蔚宝华

论文类型：期刊论文

论文概要：谭强,邓金根,孙金,刘伟,蔚宝华，Leak-off mechanism and pressure prediction for shallow sediments in deepwater drilling，Journal of Ocean University of China，2018，卷: 17 期: 1 页: 65-71

论文题目：Leak-off mechanism and pressure prediction for shallow sediments in deepwater drilling