Paper: The Thru-Tubing Bridge Plug

The economic benefits to be obtained from use of a through-tubing bridge plug have long been known by the petroleum industry. However, early attempts to produce a reliable through-tubing bridge plug for casing were not successful. Sustained engineering effort was begun by Schlumberger in the middle 60's to devise a through-tubing bridge plug that would give consistent plugging results. Many problems that had not been previously recognized were highlighted. This engineering effort produced the "Plus Plug", a new concept in through-tubing bridge plugs, which was introduced to the field in the late 60"s. Actual usage in the field has brought additional problems into focus. Additional engineering effort is being expended to improve the plus plug so that it will be capable of a wider range of usage.