页岩气层氧化改造的可行性

发布时间：2018-06-17 09:19

本文选题：页岩 + 有机质　；参考：《油气地质与采收率》2017年06期

【摘要】：体积压裂是页岩气有效开发的关键技术,其利用水力作用形成水力裂缝,沟通天然裂缝,实现缝网改造,但仍不能改善页岩基块渗透性,导致页岩气井存在改造有效期短、产量递减快等问题。通过分析页岩中有机质和黄铁矿等还原环境产物,测试有机质吸附能力,分析页岩有机质和黄铁矿氧化对气体传输能力的影响,探讨页岩氧化增渗的地质条件和工程可行性。研究结果表明:页岩普遍发育有机质和黄铁矿等易被氧化的还原环境产物;氧化页岩中有机质和黄铁矿可影响页岩气体的传输能力;有机质氧化后易形成有机酸,氧化后溶液p H值可低至3,从而溶蚀方解石等碳酸盐矿物;氧化已用于过热蒸汽钻井、消除滤饼、压裂液破胶、杀菌解堵、热采和增产处理等方面,为在工程应用过程中利用氧化改造页岩气层提供了重要经验。页岩气层氧化改造,可溶蚀有机质、黄铁矿和部分碳酸盐矿物,从而产生溶蚀孔缝,形成高温、高压环境,改变页岩气层的矿物组成、孔隙结构和吸附/解吸等特性,进而达到改造页岩气层的目的。
[Abstract]:Volume fracturing is the key technology for the effective development of shale gas. Hydraulic fracturing is used to form hydraulic fractures, to communicate natural fractures, and to realize fracture network reconstruction. However, the permeability of shale base block can not be improved, which leads to the short period of life of shale gas well reconstruction. Problems such as rapid decline in production. By analyzing the environmental products such as organic matter and pyrite in shale, the adsorption capacity of organic matter is tested, the influence of oxidation of organic matter and pyrite on gas transport ability is analyzed, and the geological conditions and engineering feasibility of oxidation and infiltration of shale are discussed. The results show that organic matter and pyrite are widely developed in shale and oxidized environmental products such as pyrite, organic matter and pyrite in oxidized shale can affect the gas transport ability of shale, organic acid is easy to form after organic matter is oxidized, The pH value of the oxidized solution can be as low as 3, thus eroding carbonate minerals such as calcite, and oxidation has been used in superheated steam drilling, eliminating filter cake, breaking glue of fracturing fluid, sterilizing and removing plugging, thermal recovery and production increase treatment, etc. It provides an important experience for using oxidation to transform shale gas reservoir in engineering application. By oxidation and transformation of shale gas layer, organic matter, pyrite and some carbonate minerals can be dissolved, resulting in dissolution pore fracture, forming high temperature and high pressure environment, changing mineral composition, pore structure and adsorption / desorption characteristics of shale gas layer. Thus, the purpose of reforming shale gas reservoir is achieved.
【作者单位】：页岩油气富集机理与有效开发国家重点实验室;西南石油大学石油与天然气工程学院;
【基金】：国家自然科学基金项目“富有机质页岩氧化致裂增渗加速气体传输机理研究”(51674209) 非常规油气层保护四川省青年科技创新研究团队项目“水力压裂页岩气井热处理解除损害及强化产能研究”(2016TD0016)
【分类号】：TE37

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