换热单元体展布特征对水平井多级压裂的EGS采热的影响  

IMPACT OF HEAT TRANSFER UNIT DISTRIBUTION CHARACTERISTICS ON HEAT EXTRACTION FROM EGS WITH HORIZONTAL WELLS USING MULTISTAGE FRACTURING

作　　者：翟海珍[1] 金光荣 古锐开 苏正[1] 刘丽华[1] 金云龙 Zhai Haizhen;Jin Guangrong;Gu Ruikai;Su Zheng;Liu Lihua;Jin Yunlong(CAS Key Laboratory of Gas Hydrate,Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development,Guangzhou Center for Gas Hydrate Research,Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences(CAS),Guangzhou 510640,China;Environmental Geological Prospecting Institute of Guangdong Province,Guangzhou 510080,China;Guangdong Hydrogeology Battalion,Guangzhou 510510,China)

机构地区：[1]中国科学院广州能源研究所,天然气水合物重点实验室,广东省新能源和可再生能源研究开发与应用重点实验室,广州天然气水合物中心,广州510640 [2]广东省环境地质勘察院,广州510080 [3]广东省水文地质大队,广州510510

出　　处：《太阳能学报》2020年第7期64-72,共9页Acta Energiae Solaris Sinica

基　　金：中国科学院天然气水合物重点实验室开放基金(y807jf1001);国家自然科学基金(41776071)。

摘　　要：借鉴页岩气等低渗透非常规油气资源体积压裂技术,水平井分段多级压裂技术可用于构建增强型地热系统(EGS)人工热储。基于EGS储层压裂呈现出的较强非均匀性,构建EGS水平双井非均匀多级压裂模型,通过调整换热单元体(HTU)厚度、展布类型分别设计多组算例,研究换热单元体展布特征对水平井多级压裂的EGS采热的影响。为表征换热单元体展布的非均匀性,引入优势厚度比的概念。研究结果表明:非均匀压裂的热储层中,系统产出温度与压裂级数呈不严格的正相关性,还受到换热单元体展布特征的影响,与储层换热单元体的优势厚度比呈负相关性;非均匀压裂的热储层中,通过封堵劣势换热单元体或增强储层压裂使换热单元体均匀化,均可增强系统的采热性能。By referring to the volume fracturing technology widely used in shale gas and other unconventional oil and gas resources with low-permeability,the segmented multistage fracturing technology of horizontal wells can be introduced to construct the EGS(Enhanced Geothermal System)artificial reservoir.Since the EGS reservoir fracturing exhibits in a form of strong non-uniformity,a horizontal dual-well non-uniform multistage fracturing model is constructed.By adjusting the thickness and distribution types of heat transfer unit(HTU),several sets of cases are designed to study the influence of HTU distribution characteristics on heat extraction performance of EGS using multistage fracturing in horizontal wells.In order to characterize the non-uniformity characteristic of HTU distribution,the new concept of preference thickness ratio is introduced.The results show that in non-uniform fracturing EGS reservoirs the production temperatures are not strictly positively correlated with the reservoir fracturing stage,and is also affected by the distribution characteristics of HTU.Moreover,the production temperatures are negatively correlated with the preference thickness ratio.In the EGS reservoir with non-uniform fracturing,the heat extraction performance can be enhanced by plugging the inferior HTU or strengthening the fracturing of the reservoir to make an homogeneous HTU.This study has certain guiding significance for the fracturing of reservoirs and the construction of artificial thermal reservoirs in EGS geothermal field.

关 键 词：地热能 水平井 计算机模拟 增强型地热系统(EGS) 多级压裂 换热单元体(HTU) 

分 类 号：P314[天文地球—固体地球物理学]