四川盆地东部页岩气水平井裂缝识别方法及应用

Method for identification of fractures in shale gas horizontal wells in eastern Sichuan Basin and its application

彭勇民 董世雄 边瑞康 杜伟 乔辉 刘曾勤

PENG Yongmin DONG Shixiong BIAN Ruikang DU Wei QIAO Hui LIU Zengqin

1. 中国石化 石油勘探开发研究院, 北京 102206; 2. 中国石化页岩油气勘探开发重点实验室, 北京 102206; 3. 页岩油气富集机理与高效开发全国重点实验室, 北京 102206

1. SINOPEC Petroleum Exploration and Production Research Institute, Beijing 102206, China; 2. SINOPEC Key Laboratory of Shale Oil/Gas Exploration and Production Technology, Beijing 102206, China; 3. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development, Beijing 102206, China

根据地质(岩心)、成像测井、测井评价、地震预测等资料，利用四川盆地东部南川—武隆地区裂缝与气测关系，研究了页岩气水平井裂缝的识别方法。针对该区岩心、成像测井缺乏和页岩气水平井的天然裂缝难识别，首先从地质上通过直井建立起岩心尺度级别的页岩天然裂缝识别模式，岩心高角度裂缝的发育与全烃异常高值、尖峰较为吻合；其次，结合裂缝识别模式，基于全烃信息可快速、低成本定性识别出无取心直井裂缝发育层段，在裂缝发育段中会出现全烃值突增的现象，特别是低有机碳含量(TOC)的页岩段，全烃值的突增代表着裂缝的存在；最后，利用TOC值与归一化全烃相关性图版法，定量识别无取心、无成像测井资料的直井与水平井裂缝段，将归一化全烃值大于等于0.4、TOC值大于等于0.5%所圈定的区域作为水平井裂缝发育段。基于识别出的水平井裂缝段，从地质—工程一体化角度出发，压裂时可提前避开或注意这些密集发育的大型或巨型裂缝，从而提高单井产量。

The relationship between fractures and gas logging in Nanchuan-Wulong area in eastern Sichuan Basin is utilized to study the identification of fractures in shale gas horizontal wells based on geological (core), imaging logging, logging evaluation, seismic prediction, and other data. First, to solve the problems of lack of core and imaging logging and difficulty in identifying natural fractures in shale gas horizontal wells, a core scale shale natural-fracture identification model is established through vertical wells from a geological perspective in this paper, and the development of high angle fractures in the core is consistent with the high values and peaks of total hydrocarbon anomalies. Second, in combination with the fracture identification mode, the fracture development section of non-coring vertical wells can be quickly and qualitatively identified at a low cost based on total hydrocarbon information. There will be a sudden increase in the total hydrocarbon value in the fracture development section, especially in the shale section with low total organic carbon (TOC). The sudden increase in the total hydrocarbon value also represents the existence of fractures. Finally, the plate method of TOC and normalized total hydrocarbon correlation is used to quantitatively identify vertical and horizontal well fracture sections without coring and imaging logging data. The area delineated by a normalized total hydrocarbon value ≥0.4 and TOC ≥0.5% are considered as the fracture development section of a horizontal well. Based on the identified horizontal well fracture section, from the perspective of geological engineering integration, it is possible to avoid or pay attention to these densely developed large or giant fractures in advance, thereby increasing the production of a single well.

国家科技重大专项 (2016ZX05061)和中国石化科技部攻关项目(P21087-6、P21042-3)联合资助。

https://doi.org/10.11781/sysydz20230611960