Super-Cement for Annular Seal & Long-Term Integrity in Deep, Hot Wells

Authors: Fred Sabins, Kevin Edgely, and Larry Watters, CSI Technologies, LLC, Houston, TX.

Venue: 2007 Drilling Engineering Association Workshop, Moody Gardens Hotel, Galveston, TX, June 19-20, 2007 (http://www.dea-global.org) [external site]).

Abstract: Successful laboratory and field testing of Ultra-Seal® R and Pre-Stressed Cement will be presented. The application of these materials can dramatically reduce the costs of re-establishing annular seal integrity in deep, hot wells, thereby significantly lowering life-cycle well costs. CSI Technologies chose two cement types for further field testing in the third phase of the project to develop a “supercement” for work in high-temperature/high-pressure (HT/HP) wells. HT/HP wells often encounter problems with isolation of production zones due to cement failures. This can result in expensive repair jobs and costly shut-ins of high-volume wells. CSI determined that resin and magnesium oxide cements showed very good mechanical properties and bonding characteristics and are controllable at HT/HP conditions. The resin cement has been used successfully in more than 50 field plugging jobs and in one HT/HP squeeze job. CSI developed a second supercement formulation that is Portland cement- based and functions by generating substantial expansion during the curing process. This material functions in the confined wellbore environment by developing significant cement matrix compressive stress during cure, resulting in a compressive pre-load. In practice, the compressive pre-load functions to elevate the effective tensile strength of the material because the compressive stress must be relieved before the material can experience tensile stress. Additionally, the pre-load functions to keep the material tightly bound to the wellbore tubulars, thereby reducing the tendency of repeated stress cycles to form a microannulus.

Related NETL Projects: The goal of the related NETL project DE-FC26-03NT41836, “Supercement for Annular Seal and Long-term Integrity in Deep, Hot Wells,” is to develop a supercement capable of sealing the annuli of and providing long-term integrity in deep, hot wells.

NETL Project Contacts
NETL –Virginia Weyland (virginia.weyland@netl.doe.gov or 918-699-2041)
CSI – Fred Sabins (fsabins@csi-tech.net or 281-784-7902)