掺锰超轻支撑剂的制备及性能研究

在保证支撑剂高强度的条件下，尽可能降低支撑剂的视密度是页岩气清水压裂技术开发的关键。本工作以低品位铝矾土、微米SiO2为主原料，水玻璃、纳米SiO2、氧化锰为辅料，用等离子动态烧结和后期高温烧结法制备方法制备超轻支撑剂，探讨了不同氧化锰掺杂量和不同烧结时间对其物相成分、体积密度、视密度和承压69 MPa下破碎率的影响。并基于经典PKN压裂模型模拟超轻支撑剂在裂缝中沉降与运移规律进行研究。结果表明，成功制备了视密度为1.639 g/cm3，在69 MPa下破碎率8.91%的超轻支撑剂，其最佳氧化锰掺杂量为7.5wt%，最佳烧结温度和烧结时间为950℃和2 h。超轻支撑剂比常规支撑剂在水平方向上运移了更长的距离，支撑剂在裂缝内部的分布也相对更均匀，可以满足中深油井的清水压裂要求。

Study on the preparation and performance of Mn-doped ultra-low density proppants

Under the condition of ensuring the high strength of the proppant, reducing the apparent density of the proppant as much as possible is the key to the development of shale gas clean water fracturing technology. In this work, low-grade bauxite and micro-SiO2 were used as the main raw materials, and water glass, nano-SiO2 and manganese oxide were used as auxiliary materials. The ultra-low density proppants were prepared by plasma dynamic sintering and later high-temperature sintering methods. The effects of different manganese oxide doping and different sintering time on phase composition, bulk density, apparent density and crushing rate at 69 MPa of proppants were discussed. And based on the classic PKN fracturing model, the settlement and migration of ultra-low density proppant in simulated fractures were studied. The results showed that an ultra-light proppant with an apparent density of 1.639 g/cm3 and a breakage ratio of 8.91% under 69 MPa was successfully prepared. The optimal manganese oxide doping content was 7.5wt%, and the optimal sintering temperature and sintering time were 950℃ and 2 h. Ultra-low density proppant migrated a longer distance in the horizontal direction than conventional proppants, and the distribution of proppant inside the fracture was relatively more uniform, which can meet the requirements of clean water fracturing for medium and deep oil wells.