Abstract: In application of production rate formula for horizontal well, anisotropy and eccentricity should often be encountered, and dealing with this problem relates to the reliability of the calculated results. At present, such formulas considering these two factors were all proposed by Joshi. However, only the results from one factor or two factors were provided by Joshi without related concrete derivations, hence remaining the issues of reliability and validity of the formulas. In appendix of this paper, the production rate formulas for horizontal well considering anisotropy and eccentricity are re-deduced and new results and recognitions are obtained. The application of the formulas by Joshi and by Chen Yuan-qian indicates that: (1)the influence of anisotropy on horizontal well production rate is very obvious, and that of eccentricity on it is relatively small; (2)there exist big problems with the formula only considering eccentricity by Joshi; (3) in Joshi's formula considering these two factors, the influence of anisotropy should not be taken into account in the eccentricity term expressed by log form; moreover, the mark before the eccentricity should be plus sign but not minus sign.

Key words: horizontal well, anisotropy, eccentricity, production rate formula, comparison, application, analysis