东方1-1气田水基钻井液技术优化

Optimization of Water Based Drilling Fluid Technology for Dongfang1-1 Gas Field

东方1-1气田为我国海上最大的自营气田,由于地层的复杂性,且由于区块已开采多年,导致地层压力衰竭,φ311.15 mm井段存在着憋漏、溢流和卡钻等作业风险。针对东方1-1气田现场PLUS/KCl钻井液抑制性能和封堵性能的不足,通过引入胺基硅醇PF-HAS和润湿转向剂PF-HWR,将钻井液体系的抗钻屑污染能力提高了近一倍;通过大量实验优选出强化封堵的材料PF-LSF和PF-HFD,增强了钻井液对渗漏和微裂缝漏失的封堵能力,形成的封堵层承压能力强,渗漏量小。优化后的体系有利于保障类似区块和地层钻井作业安全,降低作业风险。

The Dongfangl-1 gas field is the largest offshore gas field in China. Complexity of the formations plus a long time of production, result in depleted formation, and mud losses （at overpressure）, well flow and pipe sticking are thus risks that might be encountered in the 311.15 mm interval. Presently the drilling fluid used in the Dongfang 1-1 gas field is Plus/KC1, which is weak in inhibitive capacity and mud loss control. PF-LSF, an amine based silanol, and PF-HWR, a wetting alteration agent, are introduced into the Plus/KCl fluid to double the drilled cuttings tolerance of the fluid. PF-LSF and PF-HFD, plugging agents selected through extensive laboratory studies, are added into the fluid to improve its performance of mud loss control, and the barrier to mud losses generated by these plugging agents also enhance the resistance of weak formations to pressure, which is beneficial to safe operation in similar blocks and formations.