Thomas Wayne Ray

High Pressure/High Temperature (HP/HT) Seals for Oil and Gas Production

The drilling and completion of wells between 15,000 and 20,000 feet vertical depth has been actively pursued since the early 1950s because of the increased production capacities associated with these deeper wells. The high temperatures and high pressures inherent to this type environment, however, require special equipment to withstand the demands of the severe conditions to which the equipment will be subjected. Selecting seals or sealing systems for oil and gas production necessitates a comprehensive knowledge of the chemistry of both the seal material(s) and the conditions of the environment in which the seals will be used. Understanding the unique characteristics of viscoelastic response is the key to understanding elastomers in general and applying them to specific uses. This paper will discuss elastomer usage as sealing media in the oilfield ; specifically, the use of polymeric seal materials will be followed from their usage in the oilfield from 1977 to the present and their evolution to the elastomeric element packages that have been developed for todays needs in traditional as well as in severe service and high pressure/high temperature (HP/HT) applications. Of particular interest will be testing to which the newly developed seal element packages have been subjected. including the testing that was conducted in a deep well simulator. Case histories will support the enhanced capabilities of the new generation of polymeric seal assemblies. In addition to the new generation of elastomeric sealing packages, composite sealing materials have also been developed for certain applications in which elastomeric materials have not been able to provide long-term integrity. Progress being made in this area will also be discussed.

Nonelastomeric sliding sleeve maintains long term integrity in HP/HT application : Case histories

The problem of erosion that sealing systems subjected to high pressure equalization have exhibited has been a challenge to designers of downhole completion equipment for a number of years. The increase in the drilling and completion of wells between 15,000 and 20,000 feet vertical depth in pursuit of the increased production capacities associated with these deeper wells has further intensified this problem. The high pressures and temperatures inherent to the deeper environments accelerate seal degradation, and subsequently, have increased the need for more specialized sealing packages that will maintain integrity in severe service conditions. Although the capabilities of a new generation of polymeric seal materials have been significantly enhanced, in certain extreme conditions, they still have not been able to provide the necessary long-term degree of sealing efficiency required for applications such as those requiring sliding sleeve devices for high pressure/high temperature (HP/HT) applications or applications in which high pressure equalization of tubing and annulus pressure is required. This paper will present a new sliding sleeve device that employs a newly developed nonelastomeric sealing system that can maintain completion integrity in systems that must withstand high temperature and rigorous equalization of pressure.

Case Histories Verify Long-Term Operational Integrity of New Nonelastomeric Sliding Sleeves in All Wellbore Conditions

The increase in the drilling and completion of wells between 15,000 and 20,000 feet vertical depth in pursuit of the increased production capacities associated with these deeper wells has challenged designers of downhole completion equipment for a number of years. One of the primary problems in these wells has been the erosion that sealing systems subjected to high pressure equalization have exhibited. The high pressures and temperatures inherent to the deeper environments accelerate seal degradation, and subsequently, have increased the need for more specialized sealing packages that can maintain integrity in severe service conditions. Although the capabilities of a new generation of polymeric seal materials have been significantly enhanced, in certain extreme conditions, they still have not been capable of providing the necessary long-term degree of sealing efficiency required for many applications. New completion technologies that require sliding sleeve devices for high pressure/high temperature (HP/HT) applications or for applications in which high pressure equalization of tubing and annulus pressure continue to be developed. Thus, the need to develop sealing integrity for the more corrosive conditions has also increased. Developmental efforts have finally succeeded in providing an enhanced sealing system that can meet these needs. A new sliding sleeve device that employs an innovative nonelastomeric sealing system capable of maintaining completion integrity in systems that must withstand high temperature and rigorous equalization of pressure will be the primary topic of this paper. The case histories discussed will provide data that illustrate the capabilities of the new sleeve in many types of completions and will show that the sleeves have provided long-term integrity and reduced maintenance requirements. In analysis of production potentials and cost efficiency, these benefits are significant in the planning of developmental strategies.