基于示踪剂返排的致密油压裂缝网评价方法  

Techniques for Assessments of Hydraulic Fracture Network in Tight Oil Reservoirs Based on Tracer Discharging

作　　者：李林凯[1,2,3] 姜汉桥 李俊键[1] 孟凡乐[1] 秦积舜 

机构地区：[1]中国石油大学(北京),北京102249 [2]中国石油勘探开发研究院,北京100083 [3]University of Calgary, Calgary Alborta T2N1N4, Canada

出　　处：《特种油气藏》2017年第5期102-106,共5页Special Oil & Gas Reservoirs

基　　金：国家重点基础研究发展计划“973”计划“陆相致密油高效开发基础研究”(2015CB250900);国家自然科学基金“多段压裂水平井示踪剂单井吞吐运移机理及缝网识别方法”(51674271)

摘　　要：由于致密油藏渗透率极低,常采用多级水力压裂提高单井产能,压裂后形成复杂的裂缝网络。针对压裂缝网表征的问题,在压裂过程中,示踪剂添加到压裂液中注入油藏并返排至地面,基于示踪剂返排曲线,运用时间矩理论,建立了累计流动能力与累计储存能力图版用于评价裂缝网络。研究结果表明:在半对数坐标系下,示踪剂返排曲线峰值过后呈现明显的直线段。图版导数曲线能够判断压裂缝网的类型,并与微地震结果进行了验证。如果导数曲线无明显突变,裂缝网络可视为均匀分布;导数曲线有明显突变,近水平段个数代表裂缝网络主裂缝或裂缝簇的个数。该研究成果能够为地质模型的建立提供约束,对致密油藏的开发具有十分重要的意义。With consideration to the extremely low permeability in tight reservoirs, multi-stage hydraulic fracturing operations are required to enhance productivities of individual wells. Such fracturing operations may generate com- plicate fracture networks. To characterize network of these hydraulic fractures, tracers era1 be deployed in fractnring fluids during implementation of such fracturing operations. Through eumprehensive application of curves of tracer discharging and the time moment theory, the chart for assessments of fracture network with capacity to determine cu- mulative flow and preservation ean he established. Research results show under the semi-logarithmic coordinate, tracer-discharging plots are characterized by obvious straight line features after the peak. Derivatives of the chart can he used to determine properties of the hydraulic fracture network. Results of micro-seismic data were use to ver- ify relevant conclusions. In eases with no significant change in derivative curves, fracture networks may be consid- ered as evenly distritmted; In eases with significant change in derivative curves, the number of approximately hori- zontal intervals may reflect the number of main fractures or fracture clusters of fracture network. The research may play a key role in providing necessary limitations for construction of the geologic model and for developmenl of tight reservoirs.

关 键 词：示踪剂返排 压裂缝网 致密油 洛伦兹系数 时间矩理论 新疆油田 

分 类 号：TE345[石油与天然气工程—油气田开发工程]