Selecting bridging agents properly is a critical factor in designing non-damaging or low-damaging drill-in fluids. Historically, Abrams＇ rule has been used for this purpose. However, Abrams＇ rule only addresses the ...Selecting bridging agents properly is a critical factor in designing non-damaging or low-damaging drill-in fluids. Historically, Abrams＇ rule has been used for this purpose. However, Abrams＇ rule only addresses the size of particle required to initiate a bridge. The rule does not give an optimum size nor an ideal packing sequence for minimizing fluid invasion and optimizing sealing. This paper elaborates an ideal packing approach to solving the sealing problem by sealing pores with different sizes, especially those large pores which usually make dominant contribution to permeability and thereby effectively preventing the solids and filtrate of drill-in fluids from invading into formations, compared with the conventionally used techniques. Practical software has been developed to optimize the blending proportion of several bridging agents, so as to achieve ideal packing effectiveness. The method and its use in selecting the best blending proportion of several bridging agents are also discussed in this paper. A carefully designed drill-in fluid by using the ideal packing technique （named the IPT fluid） for offshore drilling operations at the Weizhou Oilfield, Nanhai West Company, CNOOC is presented. The near 100% return permeabilities from the dynamic damage tests using reservoir cores demonstrated the excellent bridging effect provided by this drill-in fluid.展开更多
用水和压缩空气在常压下对气泡雾化喷嘴进行冷态试验,研究了水平喷射时气泡雾化喷嘴雾化流中粒子分布的特征以及气液质量百分比(气液比)对粒子分布的影响。结果表明,气泡雾化和气动雾化过程雾化流中粒子的分布存在明显不同,气动雾化过...用水和压缩空气在常压下对气泡雾化喷嘴进行冷态试验,研究了水平喷射时气泡雾化喷嘴雾化流中粒子分布的特征以及气液质量百分比(气液比)对粒子分布的影响。结果表明,气泡雾化和气动雾化过程雾化流中粒子的分布存在明显不同,气动雾化过程大颗粒集中在雾化流的中心部位,而气泡雾化过程的大颗粒集中在雾化流的中下部位。气泡雾化喷嘴雾化过程雾化流中粒子分布与粒子的体积分布存在很大的差异,在试验条件下,粒子分布有着近似正态分布的特征,峰值在50μm附近;粒子体积分布的峰值后移,峰值在75μm以上,且大颗粒的体积分数远大于大颗粒数目所占的分数,更能体现喷嘴的雾化效果。提高气液比改善雾化效果不仅体现在平均粒径的大小,更重要的在于对粒子分布产生的影响,气液比提高时,小颗粒和大颗粒所占的体积分数减小,雾化流的分布更好。在SMD(Sauter Mean Diameter)约为70μm,进水量适中(400 kg/h)时,雾化流可以取得较好的粒子体积分布。展开更多
基金supported by the National Natural Science Foundation(Project No.50574061)the Changjiang Scholars and Innovative Research Team(No.IRT0411),Ministry of Education
文摘Selecting bridging agents properly is a critical factor in designing non-damaging or low-damaging drill-in fluids. Historically, Abrams＇ rule has been used for this purpose. However, Abrams＇ rule only addresses the size of particle required to initiate a bridge. The rule does not give an optimum size nor an ideal packing sequence for minimizing fluid invasion and optimizing sealing. This paper elaborates an ideal packing approach to solving the sealing problem by sealing pores with different sizes, especially those large pores which usually make dominant contribution to permeability and thereby effectively preventing the solids and filtrate of drill-in fluids from invading into formations, compared with the conventionally used techniques. Practical software has been developed to optimize the blending proportion of several bridging agents, so as to achieve ideal packing effectiveness. The method and its use in selecting the best blending proportion of several bridging agents are also discussed in this paper. A carefully designed drill-in fluid by using the ideal packing technique （named the IPT fluid） for offshore drilling operations at the Weizhou Oilfield, Nanhai West Company, CNOOC is presented. The near 100% return permeabilities from the dynamic damage tests using reservoir cores demonstrated the excellent bridging effect provided by this drill-in fluid.
文摘用水和压缩空气在常压下对气泡雾化喷嘴进行冷态试验,研究了水平喷射时气泡雾化喷嘴雾化流中粒子分布的特征以及气液质量百分比(气液比)对粒子分布的影响。结果表明,气泡雾化和气动雾化过程雾化流中粒子的分布存在明显不同,气动雾化过程大颗粒集中在雾化流的中心部位,而气泡雾化过程的大颗粒集中在雾化流的中下部位。气泡雾化喷嘴雾化过程雾化流中粒子分布与粒子的体积分布存在很大的差异,在试验条件下,粒子分布有着近似正态分布的特征,峰值在50μm附近;粒子体积分布的峰值后移,峰值在75μm以上,且大颗粒的体积分数远大于大颗粒数目所占的分数,更能体现喷嘴的雾化效果。提高气液比改善雾化效果不仅体现在平均粒径的大小,更重要的在于对粒子分布产生的影响,气液比提高时,小颗粒和大颗粒所占的体积分数减小,雾化流的分布更好。在SMD(Sauter Mean Diameter)约为70μm,进水量适中(400 kg/h)时,雾化流可以取得较好的粒子体积分布。
