煤基固体废弃物制备压裂支撑剂研究进展

Review on the preparation of fracturing proppant from coal-based solid waste

近年来我国非常规油气勘探开发取得重要进展,水力压裂技术已成为油气增产的重要措施,作为压裂技术中重要组成部分的支撑剂,其种类、参数、压裂液携带和自身运移等问题受到关注。压裂支撑剂是水力压裂过程中用于支撑裂缝使其保持张开状态的一种重要材料,是提高非常规油气采收率的关键。但压裂支撑剂面临原材料过度开采带来的资源枯竭以及生产成本高等问题,因此,与压裂支撑剂原材料成分相契合的煤基固体废弃物为原料制备压裂支撑剂备受关注。概述了煤基固体废弃物的产生、性质及综合利用现状,重点讨论了国内外煤基固体废弃物制备压裂支撑剂的研究进展。煤矸石、粉煤灰是最常见、污染最严重的煤基固废,其化学组成以SiO_(2)和Al_(2)O_(3)为主。煤矸石、粉煤灰中残余的碳和有机物在烧结过程中逸出的CO_(2)、水蒸气以及有机质的分解可产生气孔,被液相包裹形成闭气孔,起到类似造孔剂的作用,可有效降低压裂支撑剂的视密度和体积密度,提高支撑剂的导流能力。利用煤基固体废弃物制备压裂支撑剂既可有效减少天然矿物的消耗、降低生产成本和缓解环境污染,又可获得符合行业标准的压裂支撑剂,实现了煤基固体废弃物的资源化利用。最后对煤基固体废弃物制备压裂支撑剂发展和应用趋势进行展望,未来支撑剂材料向着低成本、低密度、高强度、多功能的方向发展。

In recent years,the unconventional oil and gas exploration and development has made important progress in China.Hydraulic fracturing technology has become an important measure to increase oil and gas production.As an important part of fracturing technology,proppants have attracted attention in terms of the types,parameters,fracturing fluid carrying and self-migration.Fracturing proppant is an important material for supporting fractures to keep open during hydraulic fracturing,which is the key to improve unconventional oil and gas recovery.However,fracturing proppants are faced with the problems of resource depletion and high production costs caused by over-exploitation of raw materials.In order to solve these problems,the preparation of fracturing proppants from coal-based solid wastes that are consistent with the composition of fracturing proppant raw materials has attracted much attention.The production,properties and comprehensive utilization of coal-based solid wastes were summarized.The research progress of fracturing proppants prepared from coal-based solid wastes at home and abroad was mainly discussed.Coal gangue and fly ash are the most common and polluted coal-based solid wastes,and their chemical compositions are mainly composed of SiO_(2) and Al_(2)O_(3).Pore can be produced by CO_(2),water vapor and organic matter in the residual carbon and the decomposition of organic matter in coal gangue and fly ash during the sintering process,which are wrapped by the liquid phase to form closed pores,playing a similar role as pore-forming agent,to effectively reduce the apparent density and volume density of fracturing proppant and improve the conductivity of proppant.The use of coal-based solid waste to prepare fracturing proppants cannot only effectively reduce the consumption of natural minerals,reduce production costs and alleviate environmental pollution,but also obtain fracturing proppants that meet industry standards,realizing the resource utilization of coal-based solid waste.Finally,the development and application trends of fracturing proppants prepared from coal-based solid wastes were prospected.Proppant materials will develop towards low-cost,low density,high-strength and multi-functional development direction in the future.