Commonly used methods for design of rod pumping installations presume vertical wells. This paper introduces a wave equation methodology which applies to wells that are deviated, either intentionally or unintentionally. Restrictions on surface locations and interest in horizontal drilling are increasing the number of deviated wells needing to be designed. Together with long standing crooked hole problems, these are promising subjects for further study.
This paper describes a predictive method that applies to 3 dimensional problems. A study is made of a well deemed too crooked to pump and a procedure is presented for designing intentionally deviated wells. The relative friction effects of rod guides are discussed and the effect of borehole path on power consumption is treated. The concept of dogleg severity is examined and deemed inadequate as a measure of difficulty in pumping deviated wells. The type of errors that result when vertical hole diagnostic methods are applied to deviated holes is discussed. Finally a new formulation of the radius of curvature concept is derived together with techniques for deducing rod-tubing friction from dynamometer valve checks. Comparisons with actual measurements are included to demonstrate the validity of the methods.
It is concluded that deviated wells can be adequately designed with wave equation methods. Also it is seen that highly deviated wells can be produced with rod pumping equipment when care is taken to control the path of the borehole. This paper should be considered as a progress report since much remains to be learned about application of the technology.