Mini-pipe testing has been used to expose miniature low-alloy carbon steel pipes to one-sided and two-sided hydrogen sulfi de (H 2 S) combined with high internal pressures (20,000+ psi) and axial loads. This paper explains the types of tests that have been performed and the results that have been observed. One-sided vs two-sided H 2 S exposure combined with stress gradients across the pipe wall is shown to lead to differences in pipe performance. Test results indicate a substantial increase in pipe material performance when one-sided H 2 S exposure is taken into account compared with two-sided H 2 S exposure. Tests of prenotched mini-pipes are introduced, which indicate that a fracture mechanics formula using K ISSC from the double-cantilever beam (DCB) test is nonconservative and overpredicts the pipe failure pressure due to sulfi de stress cracking. Use of the limiting value, K ISSC-Limit , is shown to improve the prediction of pipe cracking failure signifi cantly, making it almost conservative. Use of K ISSC-Limit combined with a design factor accounting for DCB uncertainty fi nally makes the fracture formula a conservative predictor of C110 pipe cracking. Tests of mini-pipes without preexisting notches are shown to indicate that a fracture mechanics formula alone cannot reliably predict pipe cracking performance; i.e., the tests indicate that both a three-dimensional stress formula and an improved fracture mechanics formula are needed to conservatively predict pipe material performance in H 2 S. The tests of mini-pipes have been consistent with tests conducted by the American Petroleum Institute (API, Washington, DC) on full-sized casing. Three-dimensional mini-pipe testing is shown to be a tool to better understand and quantify pipe per-formance in H 2 S. Results to date suggest that much understanding and benefi t can be gained through additional threedimensional testing by the sour testing community. SUMMARY OF KEY OBSERVATIONS FROM MINI-PIPE TESTSBecause of their three-dimensional (hollow) nature, mini-pipe tests have been able to quantify a difference between pipe performance with one-sided and two-sided H 2 S exposure. For a high-quality sample of C110 material in 100% hydrogen sulfi de (H 2 S), the pipe performance improved roughly 10% under onesided H 2 S exposure. However, for a poor-quality, lower-strength sample of T95 material, the improvement of pipe performance was much greater, on the order of 75% gain upon changing to one-sided (inner diameter [ID]-only) H 2 S exposure. Differences between pipe-material performance under one-sided and twosided exposure to H 2 S can be used to advantage in the design of well casing.Mini-pipes tested in H 2 S have been able to match the passing and failing behavior of full-sized (full-wall) casing made of the same T95 material and tested in H 2 S by the American Petroleum Institute (API, Washington, DC). This seems to indicate that the reduced wall thickness of the mini-pipe does not impact its passing vs failing performance compared with full-0010-9312/08/00...
Shell Exploration and Production Company (SEPCo) has spent millions of dollars since 1980 to qualify connections for well service pressure greater than 8,000 psi internal differential pressure. Prior to 1998, API RP 5C5(1) was used to qualify connections. Since 1998, SEPCo has been qualifying connections consistent with ISO 13679:2002(2). These connections have been qualified by testing, by product line qualification, or through extrapolation/interpolation from fully tested connections. In light of the potential for corrosion on metallic surfaces or handling damage, SEPCo requires that the connections for wells above 8,000 psi have two different types of sealing mechanisms: a metal seal and an independent resilient seal. Qualification and usage of tested connections with two proven seals has resulted in only four connection issues in wells (all attributed to incorrect rig make-up) over the last 20 years. The actual connection test data are the property of the thread design company. For details of any of the test protocols and results, the appropriate thread design company should be contacted. Qualification Method Appendix A lists connections which SPECo uses for well service above 8,000 psi differential pressure. In many cases these connections are rated to much higher pressures; some are rated to 15,000 psi and 18,000 psi. Similarly, all of these connections have maximum pressure ratings (above 8,000 psi), and the load-pressure usage envelopes are different for the respective connections. Details of these ratings are available from the thread design companies. ISO 13679:2002, an industry test protocol to qualify connections, is used by SEPCo to qualify connections. ISO 13679 testing requirements include internal and external pressure, tensile and compressive loading, bending and elevated temperature tests.
TX 75083-3836, U.S.A., fax 01-972-952-9435.z` AbstractDesigning casing for ultra-high pressure, high temperature (HPHT), hydrogen sulfide bearing wells creates a need to characterize the sour performance uncertainty (scatter) of higher strength, low alloy carbon steels casing such as grade C110. Casing properties generally vary by: source mill, degree of hot working, product type (seamless pipe vs. electric resistance welded pipe), steel chemistry, size and wall thickness, particular heat lot, particular joint of pipe, and location on the joint of pipe. Measured properties also can vary according to the number of and choice of laboratories doing the testing. All of these factors can contribute to the perceived scatter in the sour material properties associated with the product. In order to determine the mean and scatter of sour properties which characterize grade C110 casing and create a benchmark for the minimum possible scatter that can be achieved in a production order at a level practical for well design, Shell International E&P and Grant Prideco-TCA jointly generated a population of sour property test data across a single, commercially produced, heat lot of casing and using the services of a single NACE testing laboratory, OMNI Metals Laboratory. Grade C110 is a high strength sour service material, which is currently being considered for standardization by the American Petroleum Institute (API). This paper details the results of sixty-six NACE Method D (DCB) tests and seven NACE Method A (tensile) tests conducted across one single, commercial production heat lot of Grant Prideco-TCA grade C110 low alloy carbon steel. All tests were conducted at OMNI Metals Laboratory. The data conceptually represent the tightest possible practical spread of sour material properties since all the data were obtained from a single heat lot of pipe sampled every 10 th pipe-end and along a joint of pipe within the single lot. Hardness was found to be remarkably uniform. Results of the data are correlated in terms of model uncertainty for K ISSC vs. hardness. The paper also presents a correlation between hardness measured on pipe-ends and hardness measured on the corresponding NACE specimens. Tests were performed in standard NACE A Solution and at milder conditions. For this grade material, the mean DCB results were significantly higher than the industry trend and the scatter was unusually low indicating high product consistency across the heat. Results quantify the impact of reducing the H 2 S concentration to a fit-for-purpose environment based on NACE Method D test data.
TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractShell Exploration and Production Company (SEPCo) has spent millions of dollars since 1980 to qualify connections for well service pressure greater than 8,000 psi internal differential pressure. Prior to 1998, API RP 5C5 (1) was used to qualify connections. Since 1998, SEPCo has been qualifying connections consistent with ISO 13679:2002 (2).These connections have been qualified by testing, by product line qualification, or through extrapolation/interpolation from fully tested connections. In light of the potential for corrosion on metallic surfaces or handling damage, SEPCo requires that the connections for wells above 8,000 psi have two different types of sealing mechanisms: a metal seal and an independent resilient seal. Qualification and usage of tested connections with two proven seals has resulted in only four connection issues in wells (all attributed to incorrect rig make-up) over the last 20 years.The actual connection test data are the property of the thread design company. For details of any of the test protocols and results, the appropriate thread design company should be contacted. NomenclatureHPHT -High-pressure, High-temperature ISO -International Standards Organization QA/QC -quality assurance and quality control procedures VME -von Mises equivalent stress envelope SI Metric Conversion FactorsPsi x 6.894756= kPa
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.