隔离膜水基钻井液技术研究与应用

Study and application of Water based membrane drilling fluid.

隔离膜水基钻井液以隔离膜降滤失剂CMJ-2、高效高分子包被絮凝剂JH-1、降滤失剂CFJ-1、降粘剂JN-1为主要处理剂配制而成。其中,隔离膜降滤失剂CMJ-2是一种新型有机胺天然纤维聚合物,它由天然纤维经碱化,在高温条件下裂解后,在催化剂作用下与不饱和有机胺化合物进行缩聚反应而制得。介绍了CMJ-2的膜结构特征、抗高温降滤失性和润滑性能。评价了隔离膜水基钻井液的抑制性、抗盐、抗温、抗污染及油气层保护性能。室内评价结果表明,CMJ-2能有效降低钻井液的动滤失量和动滤失速率,可以减缓或阻止钻井液及其滤液渗入泥页岩体内,延缓孔隙压力的扩散,有效防止地层水化膨胀及坍塌;隔离膜水基钻井液具有较强的抗温、抗盐、抗污染能力,在高密度条件下也具有良好的封堵能力;无荧光、无毒性,满足环境保护要求。该钻井液在青海油田马海区块的马105井和涩南2井以及新疆油田T85388井进行了应用。现场应用表明,隔离膜钻井液在井壁外围形成隔离膜保护层,阻止钻井液及其滤液进入地层,从而有效地防止了地层的水化膨胀,封堵地层裂缝,防止井壁坍塌。

Water based membrane drilling fluid is mainly composed of membrane fluid loss additive CMJ-2, high efficiency high molecule polymer encapsulating flocculating agent GFJ-1-and viscosity reducer JN-1. CMJ-2, the fluid loss additive, is a natural polymer made from cracked natural fiber and undersaturated organic amine and in this paper, its membrane structure,properties-such as thermal,stability, filtration control and lubrication are discussed in detail. Performance evaluation on the water based membrane drilling fluid is conducted in lab. Results shows that; 1) CMJ-2 reduces dynamic filter loss-and loss velocity effeetively, delays even stops invasion by drilling fluid and the filtrate, alleviates pore pressure penetration and avoid formation hydration dilatation and hole collapse; 2) the fluid performs excellent thermal stability, salt tolerance and other anti-polluting properties; 3). it is an environmentally acceptable product with no fluorescence and no toxicity. This fluid has been used in Ma105 Well of Qinghai oilfield and T85388 well of Xinjiang Oilfield, and in-situ data verified its excellence.