Abstract
A critical design component on any steam injection project is to ensure steam containment. Loss of steam containment is not only a safety hazard, but also leads to poor well performance. Large changes in temperature have always been challenging to maintaining cement integrity not only during temperature ramp up, but certainly over the life of the well. Using high temperature swellable technology as part of the design for containment has proven to be highly effective.
In the design of a well, there are multiple casing strings, each with containment criteria and challenges. Challenges typically are due to difficulties in placing the cement and uncertainties on borehole shape. For years swellable packers have been used in conjunction with cement to overcome these challenges where cement alone has a low probability of providing successful containment. These challenges become more difficult in steam applications. Advancements in packer design and elastomer technology has led to the development of packers that can be run in casing designs which will encounter temperature up to 575°F (302°C). During the well design, critical containment areas are reviewed and consideration for the inclusion of a high temperature swellable packer is performed.
An operator of a cyclical steam injection project typically has seen steam at surface within days or weeks after initial heat up of the well. This results in additional steps to operate, maintain, and report on the well. High temperature swellable packers were piloted over a selected number of wells. It was found that wellhead pressure on cemented annuli was eliminated or significantly reduced after the first cycle of steam injection. The practice of including the packers now is used on every well and success is still being observed after multiple cycles of temperature. This reduces safety hazards as well as improve performance of the wells.
