This electronic brochure highlights our capabilities and activities in the area of Research and Development in Tubular Products. Please sign our guestbook. For additional information, e-mail George K. Wolfe, Southwest Research Institute.

Research and Development in Tubular Products

Failures of steel tubular products cost the oil and gas industry more than one-half billion dollars annually, and the incidence of failure is expected to rise due to increasingly hostile environments. Much interest has been aroused in prevention of in-service failures through better development of new designs, pre-service verification of existing designs, and the development of empirical methods for improving performance.

Southwest Research Institute (SwRI) has been involved in all areas of tubular products research and development for more than 25 years. Institute personnel are skilled in the analytical and empirical development of such products as casing, tubing, drill collars, drill pipe, riser pipe, stiffened cylinders, complex joints, and threaded and welded connections. The Institute maintains a large tubular products laboratory in support of these activities, with special capabilities for:

Full-scale fatigue and fracture testing to four million pounds
Downhole and subsea environmental simulation
External pressure vessels to 90 in I.D. x 20 ft deep, and capacity to 30,000 psig
Sour gas laboratory capable of high concentrations of H₂S, CO₂, methane, and other downhole mixture combinations
Temperature cycling of downhole connections while subjected to high axial loading, internal gas pressure, and internal spray quenching
Realistic simulation of rig-floor connection handling practices using a 12-1/4- in I.D. x 1150 ft deep test hole and actual drilling rig, or a specially designed laboratory test stand
Full analytical and experimental stress analysis capabilities, including finite element, strain gage, photoelastic, and stress-coat analyses
On-site, real time, computer-assisted data collection, reduction, and analysis
Custom design, fabrication, and installation of specialized tubular product testing equipment

At SwRI, tubular joints in offshore platforms are often evaluated under a variety of complex loadings by analytical means. However, prior to widespread application of an analytical model, a physical model is frequently made and the results compared to the analytical prediction. Here a quarter-scale model of one side of an offshore platform is subjected to an equivalent heave loading, and the strains in the members are monitored. These results are transferred back to the analytical model for comparison and validation of the model for parametric studies.

The integrities of downhole tubular connections are significantly affected by the practices used when connecting them. In a program conducted on Institute grounds, several types of commonly used premium connection designs were studied using a full-scale drilling rig. The program was successful in verifying a number of commonly held, but previously unproven, beliefs about proper makeup, and in identifying several unsuspected causes of damage.

Subsea pipelines are subjected to many different loading regimes, ranging from high tension and bending as the pipe comes off the lay-barge, to high external pressure at service depth. In an SwRI study, engineers were able to simulate these complex loadings using loading apparatus that could be operated from outside a large pressure vessel.

The search for petroleum in areas where deep hot and sour conditions exist requires that tubular performance be measured directly against such environment. In a unique SwRI facility, CRA tubular connections are evaluated at conditions of high load (500 kips), high pressure (15,000 psi), high temperature (500 degrees F), and a variety of sour well fluids, which include intruding H₂S, CO₂, methane, and brine. This facility is completely computer-controlled, with eight stations that can be set and controlled independently.

With the increased use of highly alloyed and less damage-resistant steels in the production strings of corrosive wells, the problem of connection galling during make-up has become much more important in recent years. In this laboratory study, premium connections made from 13-chrome and 25-chrome materials were subjected to repeated make-up and break-out sequences to study the resultant damage characteristics.

This brochure was published in May 1990. For more information about research and development in tubular products, contact George K. Wolfe, Mechanical Engineering Division, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510, Phone (210) 522-2428, Fax (210) 522-3042.

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