致密灰岩水平井复合缝网加砂压裂技术研究与矿场实践  

Research and application of composite fracture network sand fracturing technology for tight limestone in horizontal well

作　　者：古永红[1,2] 周长静 马占国[1,2] 肖元相 何平[1,2] 曹庾杰 杨尚儒[1,2] Gu Yonghong;Zhou Changjing;Ma Zhanguo;Xiao Yuanxiang;He Ping;Cao Yujie;Yang Shangru(National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields;Oil and Gas Technology Research Institute,PetroChina Changqing Oilfield Company)

机构地区：[1]低渗透油气田勘探开发国家工程实验室 [2]中国石油长庆油田公司油气工艺研究院,陕西省西安市710018

出　　处：《中国石油勘探》2024年第3期159-169,共11页China Petroleum Exploration

基　　金：中国石油天然气集团公司科技项目“长庆页岩油/致密气体积改造技术提升攻关与现场试验”(2022ZS0602)。

摘　　要：鄂尔多斯盆地太原组石灰岩资源丰富,是长庆油田天然气勘探开发的重要接替领域。但由于储层致密、厚度薄、酸岩反应速率快等因素,以往多种酸压工艺均未能获得产量突破。为此,转变增产技术思路,强化裂缝扩展规律实验研究、压裂液及关键材料研发配套、体积压裂模式精细刻画,形成“多段少簇密集造缝、酸压—加砂双元复合”为一体的水平井复合缝网加砂压裂技术。通过开展大露头压裂物理模拟实验,结合储层地质特点及岩石力学特征,明确储层高脆性、低两向水平主应力差、微裂缝发育特征,采用体积压裂工艺能够实现复杂缝网改造;集“深度酸压+大规模加砂”双重技术优势,构建“水力缝网+酸蚀裂缝”相结合的高导流裂缝流动通道,结合水平井密切割压裂大幅提高裂缝改造体积;针对石灰岩高杨氏模量、高破裂压力、高裂缝延伸压力、低裂缝宽度的三高一低特征,通过提高套管承压等级、差异化裂缝铺砂设计,形成多尺度小粒径连续加砂模式,解决了高杨氏模量储层加砂难问题;基于基质、壁面、裂缝三级伤害评价,研发低伤害变黏滑溜水体系,实现高杨氏模量储层造缝、成网、携砂需求。现场试验4口井,平均单井产量为59.7×10^(4)m^(3)/d,较酸压直井提高5~20倍以上,增产效果显著。目前,水平井复合缝网加砂压裂技术已成为太原组石灰岩水平井储层改造的主体技术,为该类气藏的勘探突破及有效开发提供了有力的技术保障。Ordos Basin has abundant natural gas resources in Taiyuan Formation limestone reservoir,which is a major replacement field for gas exploration and development in Changqing Oilfield Company.However,no gas production breakthrough has been made before by using various acid fracturing technologies due to the factors such as tight limestone,thin reservoir thickness,and fast acid-rock reaction rate.As a result,after changing idea of well stimulation technology,study on fracture propagation mechanism,research and development of support technologies of fracturing fluids and key materials,and fine characterization of volume fracturing mode have been strengthened,developing an integrated horizontal well composite fracture network sand fracturing technology with“multiple stages,less clusters,dense fractures,and composite acid-sand fracturing”.Based on the physical simulation experiments on large outcrop,and combined with geological characteristics and rock mechanic properties,the reservoir characteristics of high brittleness,low difference between the two horizontal principal stresses and well-developed natural fractures are determined,and the volume fracturing technology enables to obtain complex fracture network.By applying the double technological advantages of“deep acid fracturing+large-scale sand fracturing”,a high-conductivity fracture flow pathway with“hydraulic fracture network+acid corrosion fracture”has been constructed,which supports to significantly increase fracture volume together with densely cutting fracturing in horizontal well.In view of the limestone characteristics of high Young’s modulus,high fracture pressure,high fracture propagation pressure and low fracture width,the anti-pressure level of casing pipe has been improved and differential design of sand placement for fractures has been conducted,forming a continuous sand adding mode with multi-scale small size proppants,which solves the problem of difficult sand fracturing of reservoir with high Young’s modulus.Based on the three-level

关 键 词：鄂尔多斯盆地 太原组 致密灰岩 酸压 高杨氏模量 水平井 缝网加砂压裂 

分 类 号：TE377[石油与天然气工程—油气田开发工程]