摘要
天然气水合物泥质粉砂岩储层具有弱胶结、强度低等特性,水合物分解,储层强度降低,渗流通道宽度减小甚至闭合。“双增”改造浆液是一种固化后能增强储层强度与渗透率的浆液,但双增浆液的流变性质与压裂液差异较大且不含砂,浆液劈裂施工参数对射孔簇内浆液扩展情况的影响机理尚不明确。本文基于扩展有限元法建立了二维水合物储层劈裂注浆数值模拟模型,研究射孔参数与劈裂模式对裂缝扩展的影响规律。研究结果显示:射孔簇间距诱导应力场在射孔簇间距较小时对裂缝扩展影响较大,浆液扩展转向明显,随着射孔簇间距的增大,簇间应力干扰逐渐减小,原始地应力对浆液扩展方向起主要作用;相同簇间距下射孔数量越多,簇间应力干扰越强,射孔簇间距越小;同步劈裂模式下浆液扩展距离不均匀,顺序劈裂与交替劈裂时,先前形成的裂缝会被逐渐挤压,裂缝宽度逐渐变小,增加了后续射孔簇的起裂压力,不利于储层起裂。研究结果为天然气水合物储层劈裂注浆设计提供了一定参考依据。
Natural gas hydrate muddy siltstone reservoirs are characterized by weak cementation and low strength.Hydrate decomposition reduces the strength of the reservoir and the width of the seepage channel decreases or even closes.The“double‑added”reforming slurry is a type of slurry that can enhance the strength and permeability of the reservoir after curing,but the rheological properties of the double‑added slurry differ greatly from those of the fracturing fluids and it does not contain sand,and the influence mechanism of the construction parameters of slurry splitting on the expansion of the slurry in the shot‑hole clusters is not clear yet.In this paper,a two‑dimensional hydrate reservoir fracturing grouting numerical simulation model is established based on the extended finite element method to study the influence of shot hole parameters and fracturing mode on fracture expansion.The results show that:the stress field induced by the cluster spacing of injection holes has a greater influence on the fracture extension when the cluster spacing of injection holes is small,and the slurry extension becomes obvious,and with the increase of the cluster spacing of injection holes,the stress interference between clusters decreases gradually,and the original geostress plays a main role in the direction of the slurry extension;the more the number of injection holes under the same cluster spacing,the stronger the stress interference between clusters is,and the smaller the cluster spacing of injection holes is;the distance of the slurry extension under the synchronous splitting mode is not uniform,and the sequence splitting and intersecting splitting modes are not uniform,and the distance of slurry extension under the simultaneous splitting mode is not uniform.In synchronized fracturing mode,the distance of slurry expansion is not uniform,and when fracturing in sequence and alternating fracturing,the previously formed cracks will be gradually squeezed,and the width of the cracks will gradually become smaller,which increases the fracturing pressure of the subsequent shot hole clusters,and is not conducive to the fracturing of the reservoir.The results of the study provide a reference basis for the design of fracture grouting in natural gas hydrate reservoirs.
作者
刘喜龙
齐赟
谢鹏飞
孙骞
张国彪
李冰
LIU Xilong;QI Yun;XIE Pengfei;SUN Qian;ZHANG Guobiao;LI Bing(School of Energy Resource,China University of Geosciences,Beijing 100083,China;Key Laboratory of Polar Geology and Marine Mineral Resources,Ministry of Education,Beijing 100083,China;School of Engineering Technology,China University of Geosciences,Beijing 100083,China)
出处
《钻探工程》
2025年第4期26-36,共11页
Drilling Engineering
基金
国家重点研发计划(编号:2023YFC2811002)
国家自然科学基金面上项目“南海浅层气藏多翼人工井壁近井增渗及控砂机理”(编号:28912023038)。
关键词
天然气水合物
劈裂注浆
扩展有限元
双增改造技术
射孔簇间距
natural gas hydrate
split grouting
extended finite element
double increase reconstruction technology
perforation cluster spacing
