两段式桥堵增效技术在南堡27-平201井应用

冀东油田南堡2号构造2-27区块东三段发育多套火成岩，裂缝和孔洞发育，承压能力低，同井段深灰色泥岩坍塌压力高，安全密度窗口极窄，尤其是大斜度井垮塌与井漏矛盾异常突出，极易引发多重事故复杂。南堡27-平201井实钻过程中发生多次井漏，其中钻至井深4574 m发生钻井液失返后，进行2次桥接堵漏效果不佳，综合分析井下情况采用两段式桥堵增效技术，第一段堵漏浆以中细颗粒为主，辅助3%固结材料，实验结果显示加入固化剂后堵漏浆具备安全可泵性，堵塞层更致密，内摩擦力可提高6倍，第二段优选抗高温三角锥形树脂颗粒，充分发挥其易进入、易滞留、抗返排的特点，施工过程采取平推堵漏工艺，一次堵漏成功，后续施工未发生复漏。 

Application of Two-Stage Strengthened Bridging Technique in Well Nanpu27-Ping201

Wells drilled in the Dongsan member of the 2-27 block, the 2nd Structure in Jidong Oilfield penetrate several sections of igneous rocks with fractures, vugs and low pressure-bearing capacity. In the same interval of the wells, there are dark gray colored shales with high collapse pressure and very narrow safe drilling window. In deviated well drilling, the coexistence of wellbore collapse and mud losses is frequently encountered, resulting in many downhole accidents. In the drilling operation of the well Nanpu27-Ping201, mud losses were encountered several times. One of the severe mud losses, lost circulation, took place when drilled to 4,574 m. Bridging method was tried twice without success in controlling the lost circulation. Based on the analysis of the downhole situations, it was decided to use the two-stage strengthened bridging method to cure the mud loss. In the first stage, the lost circulation control slurry was formulated mainly with fine and medium particles and 3% solidifying agent. Laboratory test results showed that when the solidifying agent was added, the lost circulation control slurry still has good pumpability, the particles pack much denser, and the internal friction of the slurry was increased by 6 times. In the second stage, a high temperature, high-temperature resin particles in triangular-cone shape were used to control the mud loss. The resin particles are easy to go into the channels through which the mud was lost, and are easy to be retained in the channels. If it is necessary, the resin particles are also easy to flow back. The lost circulation control slurry was pushed and squeezed into the channels and the mud loss was controlled in the first try. In subsequent drilling operation, no mud losses occurred again.