钻井液漏失是制约深层超深层钻井的重要工程技术难题,储层段井漏是钻完井阶段最严重的储层损害方式。利用桥接堵漏材料对裂缝漏失通道进行封堵,是储层段钻井液漏失控制的主要方式。但是,桥接堵漏配方设计常采用经验或者半经验的方法,导致一次堵漏成功率低,堵漏效果差。通过CFD-DEM模拟（一种典型的基于欧拉—拉格朗日参考系的离散摸拟方法）,明确了架桥滞留、堆积填充、承压封堵是裂缝封堵层形成过程中的3个关键环节,考虑堵漏材料的高效架桥和致密填充,基于“绝对架桥加量”概念和紧密堆积理论,提出了承压堵漏实验配方设计新方法。采用“绝对架桥加量”为优化参数,确定配方中架桥材料加量;利用“补差法”改进了传统紧密堆积理论,克服了其对粒度分布不连续或重叠分布的各级填充材料适应性差的缺陷,确定堵漏配方中填充材料加量。室内实验和现场试验结果表明,深层裂缝性储层堵漏配方设计方法,可实现深层裂缝性储层堵漏配方快速高效设计,有效保证深层裂缝性储层堵漏配方封堵裂缝效果,有效减少堵漏配方中材料总用量,节约材料成本。提出的方法为深层裂缝性储层堵漏配方设计提供了新思路和理论依据。

Drilling fluid loss is an important engineering and technical problem that restricts deep and ultra-deep drilling, and the well loss in reservoir interval is the most serious reservoir damage mode in drilling and completion stage. It is the main way to control lost circulation to use the bridging plugging material to block the fracture leakage channel. However, the design of bridge plugging formula often adopts the empirical or semi-empirical method, leading to low plugging success rate and poor plugging effect. By the CFD-DEM simulation, it is clear that the bridge retention, accumulation filling and pressurized plugging are three key links in the formation process of fracture sealing layer. Considering the efficient bridging and compact filling of the plugging material, and based on the concept of “absolute bridge addition” and the theory of tight packing, a new experimental formula design method for pressurized plugging is proposed. “Absolute bridging amount” is used as a optimization parameter to determine the bridging material amount in the formula. The traditional compact packing theory is improved by the “complementation method”, which overcomes its defects of poor adaptability to the filling materials with discontinuous or overlapping particle size distribution, and determines the filling material addition in the plugging formula. The results of laboratory and field experiments show that the proposed method can realize the rapid and efficient design of the formula for deep naturally fractured reservoir, effectively ensure the sealing effect of the formula for deep naturally fractured reservoir and reduce the total amount of materials in the formula and save the material cost. The proposed method provides a new idea and theoretical basis for the design of plugging formula for deep naturally fractured reservoir.