狮202井区裂缝性地层堵漏技术

狮202井区井漏主要发生在N₁和E₃2地层上部，N₁地层裂缝发育，E₃2地层裂缝和溶蚀孔洞双介质储层发育，地层承压能力低，裸眼井段长，容易漏失的层位多，同一裸眼井段内高低压同层，井漏复杂处理难度大，针对该区块的地层漏失特点，引入NTS片状颗粒，该材料坚固，承压能力强，进入漏层后具有翻转能力。通过室内实验优选出一套堵漏技术配方，根据现场钻井液漏失速度设计了3种不同配方:①循环浆+1.0% NT-DS+（2%~3%） NTS （细）+（1%~3%）核桃壳（0.5~1.0 mm）+（1%~3%） SDL+（1%~3%） SQD-98，总浓度为12%~13%；②基浆+2% NTS （细）+3%核桃壳（1~3 mm）+（3%~4%）核桃壳（0.5~1.0 mm）+1% NT-DS+3% SDL+3% SQD-98，总浓度为15%~16%；③基浆+3% NTS （中︰细=1︰2）+（3%~5%）核桃壳（1~3 mm）+（3%~5%）核桃壳（0.5~1.0 mm）+（1%~2%） NT-DS+3% SDL+5% SQD-98，总浓度为25%左右，并制定了相应的现场施工方案。在狮202井区进行了4口井的试验应用，应用效果良好，堵漏成功率为100%，提高了地层的承压能力，扩大了安全密度窗口，满足后续施工要求。 

Techniques for Mud Loss Control in Drilling Fractured Formations in Shi-202 Well Zone

Mud losses mainly took place in the upper part of the N1 and E32 formations in the Shi-202 well zone. The N1 formation is full of fractures and the E32 formation is a double-medium reservoir full of fractures and solution vugs. Low formation pressure bearing capacity, long open hole, multiple lose zones in the hole and coexistence of high pressure and low pressure in the same open hole section have made it difficult to deal with the mud losses. A flaky particle material, NTS, with high compressive strength and being able to roll over when going into mud loss channels, was introduced to drilling fluid to stop and control mud losses. Based on the rates of mud losses, three mud loss control slurries were formulated through laboratory experiment:1) active mud+1.0% NT-DS+(2%-3%) NTS (fine)+(1%-3%) walnut shell (0.1-1 mm)+(1%-3%) SDL+(1%-3%) SQD-98. The total concentration of these additives was 12%-13%. 2) base mud+2% NTS (fine)+3% walnut shell (1-3 mm)+(3%-4%) walnut shell (0.5-1 mm)+1%NT-DS+3% SDL+3% SQD-98. The total concentration of these additives was 15%-16%. 3) base mud+3% NTS (medium:fine=1:2)+(3%-5%) walnut shell (1-3 mm)+(3%-5%) walnut shell (0.5-1 mm)+(1%-2%) NT-DS+3% SDL+5% SQD-98. The total concentration of these additives was about 25%. Operational program for the use of these mud loss control slurries was also developed and tried on 4 wells in the Shi-202 well zone. Good results have been obtained using the mud loss control slurries and mud losses were 100% under control. Pressure bearing capacity of the targeted formation was enhanced, widening the safe drilling window of the formation. The success of the mud loss control has satisfied the requirements of subsequent operations.