Research and application of tubeless oil production technology for small cased wells

In recent years, the small cased wells with inner diameter less than ?101.6 mm have become more popular in Linpan Oil Production Plant and have become an important part of crude oil production. But due to restriction by inner diameter of casing, the pump diameter is small and the clearance between pipe and the rod is small, which cause difficulties in liquid extraction and eccentric wear of rod-pipe. A technical concept of tubeless lift in small cased wells is presented, with completion of tubeless rod pump anchoring technology, anti-eccentric technique for hollow rod by injection molding, tubeless wellhead oil production system with lifting tools. Thus, a set of complete practical tubing-free lift technique for small cased wells is formed. The site tests show that this technique satisfies the requirements of liquid extraction and anti-eccentric wear in small cased wells, effectively reduces the production costs and is a technically reliable. It is easy to use and its cost is low, which has great significance to the efficient development of small cased wells.