软硬煤岩导流能力影响因素及正交试验

Influencing factors and orthogonal experiment for the soft and hard coal-rock flow conductivity

煤岩导流能力分析对煤层气经济有效开发十分重要。针对软硬程度不同的2种煤岩,运用导流仪研究不同因素对导流能力的影响,利用正交试验分析各参数对导流能力的影响程度并优化实验组合。结果表明:各参数对导流能力的影响程度排序为闭合压力、铺砂浓度、测试介质、支撑剂类型;不同支撑剂类型中,陶粒和树脂砂相对于兰州砂适用性更好;硬煤相比软煤导流效果更好;兰州砂以16/20目和20/40目体积比为1的铺砂方式具有更高导流能力;低闭合压力下,支撑剂嵌入是影响导流能力的主要因素,而高闭合压力下,支撑剂破碎是影响导流能力的主要因素;高铺砂浓度下,导流效果更好。研究成果为煤岩现场施工和优化压裂设计提供了理论依据,对煤层气安全开发也具有重要意义。

The flow conductivity of the coal-rock is very important to the economical and effective development of the coalbed methane.The influence of different factors on the flow conductivity of two kinds of coal-rock with different degree of hardness and softness was studied by using the flow conductivity meter.The influence degree of each parameter on the flow conductivity was analyzed through orthogonal experiment and the combination of different experimental parameters was optimized.The results show that the order of the influence of each parameter on the flow conductivity is shown as follows:the closure pressure,proppant concentration,test medium and proppant type.For different types of the proppant,the ceramsite and resin sand have better applicability than Lanzhou sand,and the hard coal has better flowing effect than the soft coal;Lanzhou sand with the sanding way when the volume ratio of 16/20 mesh and 20/40 mesh is 1 has pretty higher flow conductivity.The proppant embedment is the main factor affecting the flow conductivity at low closure pressure,while the proppant breakage is the main factor affecting the flow conductivity at high closure pressure,and high proppantusage can obtain a much better flow conductivity.The study achievements have provided the theoretical evidences for the coal-rock field application and fracturing design optimization,which also possess an important significance for the safe development of the coalbed methane.