Unloading Liquid Loaded Wells- How Conventional Solutions Contribute to Sustainability Targets

Abstract

In the normal life of an oil or gas well, sometimes the well produce water in conjunction with the desired hydrocarbons. In the initial stage of life of the wells, the wells have sufficient energy to carry undesired water through the well bore and out of well to the surface. With the passage of time, the reservoir pressure depletes, and it leads to a decrease in well production. When this occurs the flowing pressure decrease and have an adverse effect on the well to carry and remove the undesired water being produced by the well. When the well can't carry said water out of the well bore it builds up in the production tubing and the well shuts off flow to the surface. Soap sticks are deployed on the wells to generate foam and to overcome the liquid loading, thereby reducing the surface tension and lowering the fluid density.

The customer was experiencing liquid loading in many of its older gas wells which has a considerable impact on production targets. The liquid loading was a major challenge for the customer. The customer was using coil tubing and nitrogen kick off to offload the liquid loaded wells. The cost associated with nitrogen kick off was vey high. The customer was looking for a cost-effective solution to offload liquid loaded wells. This paper describes the application of Soap Sticks on liquid loaded wells and demonstrates that the use of Soap Sticks is cost effective and sustainable alternative to unloading by coil tubing. Initially, two liquid loaded wells were selected for Soap Sticks treatment. The data for two wells, Well X-1 and Well X-2 was used for analysis and to prepare best treatment plan. The Well X-1 was a deviated well with 4-1/2-inch single string completion. The well was producing 4944Mscf/d and 39 bbl/day liquids. The well was loaded up with water and was unable to deliver the desired production rates. As per the analysis, the Soap sticks were launched, and the well was unloaded successfully.

The Well X-2 located in the same field and was a vertical well with 4-1/2" single string completion. Based on historical data, this well was producing around 4310 Mscf/day. The production from this well dropped to 1704Mscf/day and it was kept dropping continusly. Prior to the field trial the liquid column height was determined, and the required number of Soap Sticks was calculated for the candidate well. Commencing the field trial, Soap Sticks were dropped in the well and wellhead pressure was building up. After several hours of pressure build up the well was opened whilst monitoring the flow rate and wellhead pressure.