Completion options to overcome liquid loading in the tail end production phase of gas wells

Research output: ResearchMaster's Thesis


This thesis is dealing with the application of so called “Velocity Strings” in gas wells. A velocity string is a production string with a smaller cross-section, which is implemented into an existing production tubing or casing to increase the velocity of the gas stream and therefore guarantee a continuous water disposal of the wellbore. A lot of gas and oil wells experience in the course of time a decrease in their production ability or in the end completely abandon their production. Factors that cause this problem are on the one hand the falling reservoir pressure and along with this the diminishing of the production velocity. On the other hand there is to recognize an increase of water accumulation in the area of the perforation. This water is coming from the reservoir and is caused by the condensation in the production tubing through temperature and pressure changes. The growth of this water production can lead to the establishing of a water column in the wellbore, which inhibits the gas production from the reservoir into the production tubing. This phenomenon is known as “Liquid Loading” of a gas well. This thesis firstly gives all the important background information of the “Liquid Loading” topic itself and summarizes the most common artificial lift methods. Furthermore, the different possibilities for “hanging off” a velocity string in the existing completion are listed. This work should also contain the current state of the art for the velocity string installation, therefore individual products and systems from German service companies are specified and described in detail. In the end these different systems are compared and the optimal solution for the Company is found.


Original languageEnglish
Award date22 Mar 2013
StatePublished - 2013