Gardner formula with an additional correction term
Yuan Xiaoyu1, Zhang Shaonan2, Meng Xianghao1, Wang Zhongv1
1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu,Sichuan 610059,China;
2. College of Resources and Environment Engineering,Southwest Petroleum University,Chengdu,Sichuan 610500,China
Abstract：Based on Gardner empirical formula,one method is proposed in this paper to reveal a more accurate relationship between the formation density and P-wave velocity through experimental study.First we estimate the formation density with Gardner empirical formula,and then we calculate the error dt between the measured density and estimated density.Taking into account the impact of the five logs GR,RD,PE,CNL,and AC on the formation density,we utilize multiple regression analysis to acquire the relation of these five elements and the error dt,i.e.the error model.Finally,the density of the Gardner formula with an additional correction term dt is obtained with the Gardner predicted value plus the predicted error.We make comparative analysis of the results of the Gardner formula,the polynomial,exponential empirical formula presented by Castagna,and the proposed method.The results show that our method has higher predicted accuracy than others.
