失返性漏失井环空动液面计算方法

The Wellbore Annuals Dynamic Liquid Level Determination for Total Lost Circulation During Drilling

漏失是目前钻井工程中经常遇见的复杂情况,其中恶性失返漏失最为严重。准确确定漏层位置对防漏及堵漏作业十分重要,但是在堵漏过程中却时常出现在知晓漏失层位及静液面的前提下堵漏成功率不高的现象,其主要原因为没有考虑恶性失返漏失时井筒中动、静态液面的差距,导致堵漏不成功。目前工程人员大多在停泵后采用电法或声纳等方法测量漏失静态页面,缺少准确确定钻井过程中漏失动态液面的方法。从钻井工程水力学角度出发,提出了基于钻井立压的漏失动态液面计算方法。能够确定钻井过程中失返漏失动态液面的位置,从而可以为堵漏作业中堵漏浆上界面位置设计提供重要依据,防止堵漏作业结束后上界面位置低于预期而导致堵漏作业失败情况的发生。

Lost circulation is often encountered during drilling process and the total lost is the most serious situation. Although sometimes the lost circulation position was exactly determined,the lost circulation control or plugging operation was failed. The main reason is the difference between wellbore annuals statistic liquid level and dynamic liquid level. Most of research currently is focused on the determination method for statistic liquid level but not dynamic liquid level. This paper presents an approach for dynamic liquid level determination based on the stand pipe pressure when the total lost circulation is happened during drilling operation. This approach could provide valuable information for the appropriate position selection of plugging slurry interface when carrying out the lost control or plugging operation and increase the success rate of plugging.