适于深部取心钻探井超高温聚磺钻井液体系研究

Experimental Study on the Ultra-High Temperature Polysulfonated Drilling Fluid System Suitable For Deep Coring Drilling

东北松辽盆地强水敏泥岩、泥页岩、凝灰岩发育,地温梯度高达4.1℃/100m。深井钻进过程中易出现井壁失稳、钻井液抗温能力不足等复杂情况,研制深部取心钻进配套用超高温钻井液具有迫切的工程需要。通过造浆土、抗温抗盐处理剂、防塌剂等处理剂优选及复配试验,完成了抗高温聚磺钻井液配方设计。钠土与凹凸棒土复配保证了高温钻井液具有合适的粘土胶粒浓度,处理剂优选在满足良好护胶性能的基础上充分考虑了其粘度效应。综合测试结果表明,该聚磺钻井液在230℃条件下连续加热滚动24h后性能稳定,且具备良好的抑制性、润滑性及一定的抗污染能力。在东北松辽盆地某深井连续取心钻进过程中取得了良好的应用效果。

Due to the presence of water- sensitive strata such as mudstone, shale and tuff, and the geothermal gradient up to 4.1 ℃/100m, some problems often occur during deep well drilling projects in the Songliao Basin, such as borehole instability and insufficient resistance to drilling fluid tem- perature. Therefore, design of the drilling fluid suitable for deep core drilling wells is of great importance and an urgent and practical demand. To this tar- get, an ultra - high temperature polysulfonated drilling fluid was developed by optimization of attapulgite, treating agents of temperature and salinity toler- ance, anti - sloughing agents and so on. A suitable clay colloid concentration was ensured by the combination of sodium bentonite and attapulgite for high temperature drilling fluid formulation. The viscosity effect was taken into account for treating agent optimization on the basis of its good colloid protective effect. Comprehensive tests show that this new drilling fluid was stable in 24 hours after hot rolling at 230℃. In addition, this fluid system has good prop- erties in rheology, inhibition and anti - contamination. It has been successfully applied to a deep coring drilling project in the Songliao basin.