Research On Proppant Transport Law Of Channel Fracture In Fracture Systems

Channel fracture is a novel fracturing technique which delivers a network of dispersive,open and infinitively conductive channels by substituting the homogeneous proppant pack instead of continuous proppant pack,overcoming the limitations inherent to restricted flow in porous media.Thus,the fracture is held open by discrete conglomerations of proppant pillars,while open channels play the role of low-resistance paths for the flow of reservoir fluids.As a result,much more production of oil and gas is extracted.lt should be pointed that the key of successful channel fracturing is to substitute the homogeneous proppant pillars.Unfortunately,there has been lack of effective means of studying the rule of proppant transportion of channel fracturing in main fracture,specially,in a network of fratures.At this point,it is meaningful to design a set of device which visullay presents the process of proppant transporation of channel fracture.Based on investigation of abundant literature,we have made several progress as follows:(1)After analysis of boundedness of exsiting devices,a set of visual apparatus used for simulation of homogeneous proppant transport in a network of fractures,by improving perforation cluster uint,pulse uint,mult-stage fracture parallel panel unit and data processing uint,is developed.(2)Based on Fluent Software,a single fracture CFD model and a mult-stage fracute with a angle of 90 CFD model are performed to verify the rationality of parameters in the designed device.(3)Abundant experiments are made to study the influences of different factors such as fracture liquid viscosity,perforation cluster and fibre on the channel ratio and distribution of proppant pillars in single fracture.At the end,sensitivity analysis of different factors is made by multi-factor analysis.(4)Futher researches of the transportion of proppant pillars in T geometry fracture network under different influential factors like secondary fracture width,proppant size,viscosity,displacement and fracture angle are made to analyse transportion rule of proppant in secondary fracture.Finally,the reseach on fracture conductivity of a certain channel ratio under different conditions of proppant displacement,proppant concentration,fiber concentration and reservoir lithology is made.The paper has provided a visualization research strategy and means for homogeneous proppant in main and secondary fractures,further revealing the mechanism of channel fracture.In addition,the results can also be a reference to channel fracturing design and treatment parameters optimization.