石英砂陶粒组合支撑剂导流能力实验研究

摘要

In order to optimize the proppant for the reservoirs with closure stress of 25-35 MPa, the FCES-100 fracture conductivity evaluation system was used to measure the percent reduction and flow conductivity of ceramsite and quartz sand that are used on site in the Changqing Oilfield, the flow conductivity of quartz sand-ceramsite mixed proppant by varying their volume ratio, and the flow conductivity of quartz sand-stern chase ceramsite proppant by varying their ratio, according to the recommended practices under SY/T 6302-2009. It is shown that, at different closure stresses, the flow conductivity of quartz sand-stern chase ceramsite proppant is higher than that of quartz sand-ceramsite uniform mixture when the volume ratio of quartz sand to ceramsite is 1:1, 2:1 and 3:1. The higher the closure stress is, the larger their difference is. In the same conditions, the stern chase type is preferred. When the volume ratio of quartz sand to ceramsite is 1:1, the mixed type is close to the stern chase type in terms of flow conductivity. As for the reservoirs with closure stress of 35 MPa, either mixed type (1:1) or stern chase type suitable, but considering the cost, it is recommended to select the stern chase type (2:1). It is suggested to adopt stern chase type (3:1) for the reservoirs with closure stress of 25 MPa and stern chase type (4:1) for the reservoirs with closure stress of 20 MPa. When the closure stress is 25-35 MPa, the proppant can provide sufficient flow conductivity if the ceramsite accounts for 50%, which can be taken as the upper limit of ceramsite. The experimental data provides the important basis for the optimization of proppant in reservoirs with in-situ closure stress of 25-35 MPa.%为优选现场压裂设计25~35 MPa 闭合应力下支撑剂，使用 FCES-100裂缝导流仪根据 SY/T 6302—2009推荐方法测量了长庆现场用陶粒和石英砂破碎率和导流能力、石英砂与陶粒不同体积比混合导流能力，以及石英砂后尾追不同比例陶粒导流能力。结果显示：不同闭合应力下石英砂与陶粒组合体积比为1∶1，2∶1，3∶1时，石英砂后尾追陶粒导流能力大于石英砂陶粒均匀混合导流能力，闭合应力越高，差距越明显，相同条件下优选尾追型；混合型和尾追型石英砂和陶粒体积比均为1∶1时，混合型导流能力接近尾追型。闭合应力35 MPa 储层，选用1∶1混合型或尾追型，考虑成本因素建议选择尾追型2∶1；闭合应力25 MPa 储层考虑成本推荐3∶1尾追型；闭合应力20 MPa 储层推荐4∶1尾追型。25~35 MPa 闭合应力下支撑剂组合中陶粒占比达到50%即可提供足够导流能力，其值可作为陶粒使用上限。实验数据为现场闭合应力在25~35 MPa 储层支撑剂的优选提供了重要依据。