火山岩岩板长期导流能力试验

An experimental study of long-term flow conductivity of volcanic rock core plate

火山岩气藏的压后效果和压裂有效期取决于压裂支撑剂的长期导流能力,以往采用短期导流能力室内数据进行压裂优化设计,不能反映真实的裂缝导流能力,导致预测的气井产能差别较大。为了得到真实的长期导流能力,采用改进的压裂支撑剂导流能力测试装置对火山岩岩板进行了长期导流能力测试,发现支撑剂在火山岩岩板上有明显的嵌入,造成导流能力明显下降,并且50h后导流能力还没有完全稳定,导流能力的变化趋势也不同于钢板长期导流能力(而钢板长期导流能力50h后的导流能力数值基本稳定)。同时,对不同闭合压力下的岩板长期导流能力和钢板短期导流能力进行了对比,得出了两者之间的关系。岩板长期导流能力提供了模拟储层条件下的真实数据,也反映了裂缝的长期导流能力变化趋势,对于准确认识火山岩气藏的生产能力有着重要意义。

Both post-frac result and effective producing time after fracturing in volcanic gas reservoirs are determined by the long-term flow conductivity of the proppant.The fracturing optimization design based on the laboratory data of short-term flow conductivity can not reflect a real flow conductivity of fractures in field practices,which results in a large difference in the prediction of a gas well's productivity.In view of this,the improved equipments on testing flow conductivity of proppant are used to test the long-term flow conductivity of a volcanic rock core plate.The experiments show that there is obvious imbedding of proppant in the volcanic rock core plate,which results in a significant decrease of flow conductivity.Furthermore,after 50 hrs,the flow conductivity of the volcanic rock core plate,unlike that of a steel plate,is still unsteady and its changing trend is also different.Meanwhile,the long-term flow conductivity of a core plate and the short-term flow conductivity of a steel plate are compared and their relationship is drawn.The long-term flow conductivity of a core plate provides the real data under the simulated reservoirs and reflects the changing trend of the long-term flow conductivity of fractures.This study is of significance for the accurate evaluation of the productivity of volcanic gas reservoirs.