卡塔尔DK-597井无损害取心钻井液工艺技术

DK-597井取心长度为220m．目的是获得贯穿整个杜汉油田储层的大量高质量、无污染岩心，收集新的数据，建立符合实际的饱和度剖面图。设计了无损害取心钻井液。该钻井液在无圃相生物聚合物钻井液基础上．添加了适当粒径的架桥粒子．如Baracarb(5)、Baracarb(50)等能够酸溶的固体颗粒，以有效形成钻井液滤饼。降低钻井液瞬时滤失量，克服无固相钻井液滤失量大的缺点；并加入了一定量的盐，使钻井液矿化度接近地层水矿化度。降低侵入滤液对岩心的损害。针对取心设计要求对该钻井液的性能进行了优选。现场应用表明，该钻井液达到了低侵入量、保护岩心的目的；而且体系性能稳定，维护方便，各处理剂间配伍性好。

The use of non-damaging coring fluid in well DK-597, Qatar

To obtain high quality, non-damaged core sample and then establish an actual profile map of degree of saturation is the purpose of well DK-597 drilling with coring length of 220 m. Non-damaging coring fluid is recommended. Based on free solid biopolymer mud and with appropriate solid bridging additives such as Baracarb(5) ,Baracarb(50) which are acid soluble, effective filter cake is formed and spurt loss is reduced. Owing to adding proper amount salt of the fluid salinity approaches that of the formation fluid, and the invasion damage to core by filtrate fluid is prevented. The fluid has been optimized according to the coring design and onsite using shows that the objectives of protecting core have been achieved because of its stable properties, easy maintenance and good compatibility with additives of the coring fluid.