摘要
岩石脆性指数是水平井压裂施工的重要参数,现有获取脆性指数的方法受限于成本高和时效性差,现场推广应用困难。基于录井岩屑资料明确其分形规律,建立岩屑分形维数计算方法,考虑岩石力学参数修正矿物组分计算脆性指数方法,获取岩屑脆性指数后,进一步建立研究区块岩屑分形维数与脆性指数相关性模型,形成基于岩屑资料快速获取岩石脆性指数方法。研究表明:水平段岩屑分形规律符合G-S分布函数,分形维数相关性系数r^(2)平均大于0.89,具有明显的分形特征;岩屑分形维数与脆性指数相关性系数r^(2)大于0.95。该方法在邻井应用效果较好,岩屑分形维数计算的岩石脆性指数与矿物组分法计算的岩石脆性指数绝对误差小于4%,该方法为脆性指数的现场推广应用提供了一种新思路。
Rock brittleness index is an important parameter in horizontal well fracturing construction.The existing methods to obtain brittleness index are limited by high cost and poor timeliness,so it is difficult to popularize and apply in the field.The fractal law is clarified,and the calculation method of cuttings fractal dimension is established based on mud logging cuttings data.Considering the rock mechanical parameters,the mineral composition to calculate the brittleness index is modified.After the cuttings brittleness index is obtained,the correlation model between cuttings fractal dimension and brittleness index in the research block is further established,and finally the method to quickly obtain the rock brittleness index has been obtained based on cuttings data.The research shows the fractal law of rock cuttings in horizontal section conforms to G-S distribution function,and the average correlation coefficient(r^(2))of fractal dimension is greater than 0.89,which has obvious fractal characteristics.The correlation coefficient(r^(2))between cuttings fractal dimension and brittleness index is greater than 0.95.The application results of adjacent wells show that the absolute error between the rock brittleness index calculated by cuttings fractal dimension and that calculated by mineral composition method is less than 4%.This method provides a new idea for the field popularization and application of brittleness index.
作者
常小龙
曹旭
刘锐
方少伯
孙志高
田泽华
CHANG Xiaolong;CAO Xu;LIU Rui;FANG Shaobo;SUN Zhigao;TIAN Zehua(CNPC XDEC Mud Logging Branch Company,Karamay,Xinjiang 834000,China)
出处
《录井工程》
2022年第4期19-24,共6页
Mud Logging Engineering
基金
中国石油西部钻探工程有限公司科技项目“基于岩屑分形算法的水平井工程甜点评价方法研究”(编号:2022XZ302)
关键词
岩屑
分形维数
修正矿物组分法
脆性指数
相关性分析
cuttings
fractal dimension
modified mineral composition method
brittleness index
correlation analysis
