Buckling of Tubing in Pumping Wells, Its Effects and Means for Controlling It (includes associated paper 1053-G)

Abstract

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 73–88. Abstract It is explained why the bottom portion of freely suspended tubing in a pumping well buckles and straightens in succession during the pumping cycle. Field evidence of resulting rod-on-tubing wear and excessive polished rod load and horsepower are given. The possibility that buckling hastens pump wear is strongly suggested. Means for either prevention of buckling or for minimizing its effects are explained, their relative merits compared, and field results of their use given. These means are: tension anchors, tail pipe, sucker rod guides, arid corrosion inhibitors Charts and formulae for best use of tension anchors, tail pipe, and guides are given. Buckling which generally occurs above compression anchors is more harmful than buckling of freely suspend tubing. Buckling above a compression anchor may be prevented by a heavy tail pipe below the pump. Introduction It is well known that a column must be subjected to some compression in order to buckle; and also that a structural member does not buckle if subjected to a tension. when consideration is given to a tubular column, the question may be asked, "How is the buckling phenomenon affected by inside or outside pressure?" At first, it would seem that it should not be affected. However, this is not so. In order to arrive at a correct answer to the question one should first understand the basic reasons for buckling of a column under loading. Then he should add to the effect of that loading the effect of pressure. Following this procedure, one may discover quite unexpected phenomena. In some cases, when subjected to more pressure inside than outside, a pipe may buckle under tension. In some other cases, a pipe may remain straight, although subjected to a very large compression.