石英砂支撑剂破碎率影响因素探讨

Discussion on Influencing Factors of Crush Resistance of Sand Proppant for Hydraulic Fracturing

水力压裂是油气田增产、增注的有效措施,其效果与支撑剂性能密切相关,而支撑剂的破碎率是重要性能指标之一。石英砂支撑剂作为支撑剂的一个重要分支,其破碎率受产地、粒径、实验条件等因素影响。选取6个代表性产地、不同粒径段的石英砂支撑剂,按照行业推荐标准SY/T 5108—2014的方法进行实验,从粒径级配、不同矿化度液体浸泡等方面进行破碎率的影响因素研究。实验结果表明,石英砂支撑剂破碎率受产地影响较大;支撑剂的粒径组成对支撑剂破碎率亦有较大影响,规格范围内细粒径颗粒越少,支撑剂破碎率越低;不同液体浸泡对破碎率影响明显,矿化水浸泡后支撑剂的破碎率明显降低。因此,对石英砂支撑剂强度要求比较苛刻的储层,可选用质量较好产地的石英砂支撑剂,以提高其裂缝中的充填性能,增加裂缝导流能力。生产过程中可通过改变粒径分布使破碎率达到合格。同时,也可以采用矿化水浸泡、清水洗涤的方式降低石英砂支撑剂破碎率。

Hydraulic fracturing is an effective measure for increasing production and injection in oil and gas fields.Its effect is closely related to the performance of proppant,and the crush resistance of the proppant is one of its important performance indexes.As an important branch of the proppant,the crush resistance of sand proppant is affected by factors such as origin,particle size and experimental conditions.According to the methods introduced by SY/T 5108-2014,three sand proppants with different particle sizes from six representative producing areas are selected to study the influencing factors of crush resistance from particle size distribution and liquid immersion with different mineralization degree.The experimental results show that the crush resistance of sand proppant is greatly affected by the origin.Composition of grain diameters of the proppant has great influence on the crush resistance of the sand proppant,and the less the particle with fine size is within the specification range,the lower the crush resistance of the proppant is;different liquid immersion has obvious effect on the crush resistance,and the crush resistance may reduce obviously after immersion by the mineralized water.Therefore,for the reservoirs with strict strength requirements of the sand proppant,the sand proppant with better quality can be selected to improve the flling performance in fractures and increase the fracture conductivity.In the production process,changing the particle size distribution may get qualified crush resistance.At the same time,mineralized water soaking and water washing can also be used to reduce the crush resistance of the sand proppant.