非常规储层压裂砂比对支撑剂铺置质量影响的实验研究

Experimental Study on the Effect of Fracturing Sand Ratio on Proppant Placement in Unconventional Reservoirs

低孔超低渗透率的非常规储层需通过大规模的水力压裂形成支撑剂填充的高导流裂缝,才能获得有经济效益的油气产量,缝内支撑剂铺置规律直接影响压裂效果,影响支撑剂铺置的因素包括施工排量、施工压力、砂比等。为了研究砂比对支撑剂在缝内铺置的影响,运用了大型可视平板垂直裂缝模拟系统,研究了不同砂比下陶粒支撑剂在裂缝中的沉降运移规律。实验结果表明,砂比对20~40目陶粒砂堤形状有影响,但砂堤形状变化较小;当陶粒砂比增加时,陶粒堆积形成的砂堤坡度减小;陶粒砂比增加,陶粒颗粒之间的碰撞作用增强,沉降量减小,砂堤高度减小;陶粒支撑剂水平运移速度受砂比影响较小,接近液体流速;陶粒砂比增加,陶粒支撑剂的沉降速度减小。研究结果可为支撑剂沉降运移动态研究及支撑剂优选提供参考。

Unconventional reservoirs with low porosity and ultra-low permeability need to form high conductivity fractures filled with proppant through large-scale hydraulic fracturing to obtain economic oil and gas.Proppant placement in the fracture directly affects the fracturing effect.Factors affecting proppant placement include construction displacement, construction pressure, sand ratio, etc.In order to study the effect of sand ratio on the placement of proppant in the fracture, a large visual plate vertical fracture simulation system was used to study the settlement and migration law of ceramic proppant in the fracture under different sand ratio.The experimental results show that the sand ratio has an effect on the shape of 20-40 mesh ceramsite formed sand bank, but the shape of sand embankment changes little.When the ceramic sand ratio increases, the slope of ceramsite formed sand bank decreases;with the increase of ceramic sand ratio, the slope of the ceramsite formed sand bank accumulation decreases.With the increase of ceramic sand ratio, the collision between ceramic particles is enhanced, the settlement decreases and the height of sand bank decreases.Horizontal migration velocity of proppant is less affected by sand ratio, which is close to the liquid velocity.Sedimentation rate of proppant decreases with the increase of ceramic sand ratio.The results can provide reference for the study of proppant settlement and transport dynamics and proppant optimization.