Controlling lost circulation during drilling operations in a reservoir prone to fluid losses is typically remedied by cement squeezing or plug setting as the last resort. The aim being to minimize or stop drilling fluid losses and to regain full returns at surface, and to maintain wellbore integrity. Different placement methods of cement plugs have been discussed in detail in the literature, except for the ‘level-off’ method, which can be effective for curing complete loss circulation cases. Following modeling and calculations of this cement plug placement method, its design and execution procedures are discussed, together with two successful field cases in highly fractured carbonate reservoirs in the Middle East. Using drill pipe and a Retrievable-Test-Treat-Squeeze (RTTS) packer, set with some spacing from the loss zone, the method entails that the cement slurry is allowed to drop by gravity in order to cure lost circulation. As the column of fluid, mud and slurry in the well exceeds formation pore pressure, i.e., overbalanced conditions, a volume of acid-soluble cement slurry is allowed to slowly drop and freely penetrate the formation, i.e., through its fractures or caverns. During the penetration of this viscous slurry into the loss zone, the cement slurry can set and the fracture or fissure openings are plugged. Presented are detailed design calculations for the level-off placement technique, determination of required cement slurry and displacement volumes, and recommended displacement and RTTS packer setting depths. The expected depth of the top of cement plug is estimated. The design parameters are compared with field cases and explanations are given for possible discrepancies. Success of the operation is discussed in terms of final mud loss after cement plugging and Non-Productive Time mitigation. Detailed field procedures and execution are also presented. The level-off job is already practiced by the industry, but it is not published in the literature, in some cases they have different methods with causing some errors. To the best of authors’ knowledge, this is the first detailed description and stepwise calculation of the level-off cement placement technique in the literature.

在容易发生流体损失的储层中进行钻井作业期间控制漏失通常通过水泥挤压或塞子设置作为最后的手段来补救。目的是尽量减少或停止钻井液损失，并在地面重新获得全部回报，并保持井筒完整性。水泥塞的不同放置方法已在文献中详细讨论，但“平整”方法除外，该方法可有效固化完全漏失情况。在对这种水泥塞放置方法进行建模和计算之后，讨论了其设计和执行程序，以及在中东高度裂缝性碳酸盐岩油藏中的两个成功现场案例。使用钻杆和可回收-测试-处理-挤压 (RTTS) 封隔器，设置与损失区有一些间距，该方法需要使水泥浆在重力作用下掉落，以解决失去的循环。当井中的流体、泥浆和泥浆柱超过地层孔隙压力，即超平衡条件时，允许一定体积的酸溶性水泥浆缓慢下降并自由渗透地层，即通过其裂缝或洞穴。在这种粘性泥浆渗入损失区的过程中，水泥浆会凝固，裂缝或裂缝开口被堵塞。介绍了平整放置技术的详细设计计算，确定所需的水泥浆和置换体积，以及推荐的置换和 RTTS 封隔器设置深度。估计水泥塞顶部的预期深度。将设计参数与现场案例进行比较，并对可能的差异进行解释。从水泥堵塞和非生产时间缓解后的最终泥浆流失来讨论操作的成功。还介绍了详细的现场程序和执行。调平工作已经被业界实践了，但没有在文献中发表，在某些情况下，他们有不同的方法，导致一些错误。据作者所知，这是文献中首次对平整水泥浇筑技术进行详细描述和逐步计算。调平工作已经被业界实践了，但没有在文献中发表，在某些情况下，他们有不同的方法，导致一些错误。据作者所知，这是文献中首次对平整水泥浇筑技术进行详细描述和逐步计算。调平工作已经被业界实践了，但没有在文献中发表，在某些情况下，他们有不同的方法，导致一些错误。据作者所知，这是文献中首次对平整水泥浇筑技术进行详细描述和逐步计算。