气制油合成基钻井液流变性能影响评价

Evaluation on rheological properties of GTL based drilling fluids

关键词:  气制油合成基钻井液  流变性  塑性粘度  动切力 

Key words:  GTL based drilling fluid  rheological property  plastic viscosity  yield stress

摘要:

针对气制油合成基钻井液体系流变性的调控问题,研究了对其流变性影响的因素。实验结果表明:乳化剂应适量,不足或过量都会对体系流变性产生一定影响;有机土、增粘提切剂、油水比和温度是合成基钻井液流变性的主要影响因素。为了获得合适的流变性,一定要控制好有机土的加量,对于未加重体系,有机土加量可适当提高3%~4%(w)；而对于加重体系,有机土加量应控制在1.5%~3%(w);随着合成基钻井液中含水量的增加,体系塑性粘度和动切力明显增大。增粘提切剂和温度对合成基钻井液粘切都有很大影响,增粘提切剂的加量应控制在1%以下,高温时可适当加入抗温剂。

Abstract:

In view of rheology control problem for gas-to-liquid (GTL) based drilling fluid system, the influence of various factors on the rheological properties was studied. The results showed that the amount of emulsifier employed should be moderate, i.e., insufficient or excessive quantity will have a certain impact on the rheological properties. Further, organic clay, viscosifier, oil/water ratio and temperature are the main factors affecting the synthetic drilling fluid rheology. The organic clay content of 3%~4% is appropriate to a non-weighting drilling fluid, while 1.5%~3% content is desirable to a weighting drilling fluid. Usually the greater the density is, the smaller the amount of the organic clay is. The plastic viscosity and yield stress of a drilling fluid can be significantly increased with an increase of water content. Viscosifier and temperature have great influences on the viscosity and gels. Viscosifier dosage should be less than 1%, and a proper temperature resistant agent should be added at high temperatures.