广谱型屏蔽暂堵保护油气层技术的探讨

he general- purpose temporary shield plugging technology in protecting hydrocarbon reservoir

采用广谱型屏蔽暂堵保护油气层钻井液技术,可以解决中高渗透率油气层和不均质储层的油气层保护技术难题,复配使用多种粒径的架桥粒子和多种粒径的充填粒子,有效封堵不均质油气层流动孔喉,在近井壁带形成渗透率接近零的屏蔽暂堵层,可以阻止钻井液固相和滤液侵入油气层,减少钻井液对油气层的损害。该技术要点为依据油气层流动孔喉直径变化规律、d流动50、dmax确定多种暂堵粒子的直径,按1/2～2/3储层的d流动50选择架桥粒子的d50,而且架桥粒子的d90应为1/2～2/3储层的dmax,其加量大干4％;按1/4储层的d流动50选择充填粒子的d50。,其加量大于1.5％。可变形粒子加量为2％,其软化点高于油气层井下温度10～50℃。

The general-purpose temporary shield plugging technology plays a main role in solving the technical problems of protecting medium-high permeability and heterogeneous reservoir. Multi-size bridging grains and multi-size infilling grains are used compatibly in the technology to plug available the pore throat of non-homogeneous reservoir and form a zero permeability temporary shield plugging zone near wellbore, thus drilling fluid solids and filter liquor penetrating reservoir can be prevented and formation damage can be reduced. The keys of the technology are: determining the diameters of multi temporary plugging grains according to the change law of available pore throat diameter d flow50 and dmax of the reservoir; selecting d50 of bridging grains according to one second to two thirds of dflow50 of the reservoir, further, d90 of bridging grains should be one second to two thirds of dmax of the reservoir and the dosage should be over 4%; determining d50 of infilling grains according to one fourth of dflow50 of the reservoir and its dosage should be over 1.5%; the dosage of deformable grains should be 2% and its softening point should be over 10-50 ℃ of the downhole temperature.