Titanium Drilling Risers—Application and Qualification

High pressure drilling risers represent the most challenging application for composite materials in the offshore industry. Therefore, their successful field qualification should serve to eliminate the emotional barriers and pave the way for the broad usage of composites in similar but less demanding applications such as production risers, catenary risers, tubings, etc. The primary goal of the project discussed in this paper is to demonstrate the technical feasibility and cost effectiveness of advanced composite materials for high-pressure drilling risers. This is achieved by the design, manufacture, qualification, certification and field testing of a 558 mm ID (22 in.) composite drilling riser joint on Heidrun Tension Leg Platform (TLP) A composite drilling riser (CDR) joint is designed to be interchangeable with the Standard Titanium Drilling Riser Joints (STDRJ's) currently in use on the Heidrun platform. The CDR joint has identical flange configurations as the titanium joints and is designed to satisfy all dimensional constraints to make it suitable for installation on Heidrun. The tube body weight of the CDR joint is 87 lb/ft versus 130 lb/ft for an equivalent Ti joint. The fatigue life of the CDR joint exceeds 150 years (10 times the 15 year service life), and its internal pressure rating exceeds 12,600 psi, which is about 2-¾ times the maximum operating pressure of 4500 psi. In addition, the CDR joint, without the need for any special impact protector, maintains its pressure and structural integrity after being subjected to a dropped object impact of 50kJ.The structural capability of the CDR tube body is provided by a carbon fiber/epoxy composite overwrap, with load transfer between the composite overwrap and Ti flange extensions accomplished through a carefully designed traplock Metal-to-Composite Interface (MCI). Detailed analysis of the CDR joint confirmed that it is capable of safely supporting all of the expected loadings, including internal and external pressures, axial tension, bending moments, and impact loads. The bore of the CDR joint is provided with a 0.125-inch (3.2 mm) Ti liner welded to the flanges for fluid-tightness and damage resistance, and an elastomeric wear liner identical to the one currently in use on Heidrun. The design, analysis and qualification of the CDR joints have benefited from the design and the extensive qualification activities on the 10-¾ inch high pressure composite production riser joints as part of the NIST ATP project.The paper summarizes the performance requirements called for by Heidrun TLP Drilling Riser System, and presents the design and analysis procedures and results to ensure that the composite riser joint satisfies all requirements. The paper reviews the basis for the analysis and the validation of its accuracy, and presents the rationale for the qualification program.

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“…The elastomeric liner is used to protect the titanium from wear [2]. The elastomeric liner is used to protect the titanium from wear [2].…”

Section: Figure 2 Compriser™ Cdr Metal Assemblymentioning

confidence: 99%

Design Consideration for Composite Drilling Riser

Salama

Murali

Baldwin³

et al. 1999

All Days

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“…Ti is also widely used in such industries as automobile (Anonymous, 1989;Yamashita et al, 2002), chemical (Farthing, 1979;Orr, 1982;Salama et al, 2000;Schutz et al, 2001), medical (Abdullin et al, 1988;Froes, 2002), metallurgic (Anonymous, 2004;Orr, 1982), military (Montgomery and Wells, 2001;Lerner, 2004), and sporting goods (Froes, 2002). The rapid advance of the application of Ti in the past several decades has been matched by a dramatic growth of the Ti industry.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Drilling Processes for Titanium Alloys: A Literature Review

Zhang

Churi

Pei

et al. 2008

Machining Science and Technology

120

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Titanium and its alloys (Ti) are attractive for many applications due to their superior properties.However, they are regarded as hard-to-machine materials. Drilling is an important machining process since it is involved in nearly all Ti applications. It is desirable to develop cost-effective drilling processes for Ti and/or improve the cost-effectiveness of currently-available processes. Such development and improvement will be benefited by a comprehensive literature review of drilling processes for Ti. This paper presents a literature review on mechanical drilling processes for Ti, namely, twist drilling, vibration assisted twist drilling, ultrasonic machining, and rotary ultrasonic machining. It discusses cutting force, cutting temperature, tool wear and tool life, hole quality (diameter and cylindricity, surface roughness, and burr), and chip type when drilling of Ti using these processes.

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“…The Ti-29 corrosion-fatigue data in the sour brine environment are shown in Figure 6-10 (red data points). For comparison, literature data on Ti-23 in air [13] are also shown (green data points), as well as RTI's recommended design curve for welded Ti-29 [12]. As can be seen the corrosion-fatigue lives out to about 4x10 5 cycles are just below the scatter of the air data, thereby indicated a mild reduction in fatigue life of about a factor of two or less due to the sour brine environment.…”

Section: Ti-29 S-n Corrosion-fatigue In Sour Brinementioning

confidence: 95%

“…It should also be pointed out that only three of the five steels assessed here are recommended for use in sour service; thus only these three steels were tested in sour brine environment. Since Ti-29 corrosion-fatigue data in sour environment are limited, testing on this material was performed in sour brine, but not in seawater since ample data in the latter environment are presently available [12][13][14][15][16][17][18][19]. Fatigue crack growth rates and S-N fatigue data were generated in three environments: 1) laboratory air, which provided a baseline for comparison of the effects of the more aggressive environments; 2) simulated seawater plus cathodic protection (SW + CP), which was prepared per ASTM D1141 and included cathodic protection at -1050 millivolts (mv) versus the Standard Calomel Electrode, to represent the external environment of the riser; and 3) a sour brine (SB) environment, which was prepared with a production brine with 35 percent hydrogen sulfide (H 2 S) and 65 percent carbon dioxide (CO 2 ) and oxygen below 10 parts per billion (ppb), to represent the internal environment of the riser.…”

Section: Materials and Environmentsmentioning

confidence: 99%

“…Typical S-N fatigue strip specimen and examplecutting plan for specimen removal from pipe; depending on pipe diameter, three-to-five specimens were removed from each pipe segment ................................................................. Photograph of convex and concave brass inserts used in the grips to apply a uniform clamping force across the curved section of the strip fatigue S-N specimens .............................................................................................................. 10 4-4 Triple-containment chamber components for S-N fatigue testing in sour brine environment ................................................................................................ Summary of fatigue crack growth rate data for five different steels in lab air showing trend, at a given ∆K, of increasing rates with increasing material yield strength (YS) ................................................................................................. 13 5-2 Frequency-scan results in 848 MPa YS steel in seawater environment ............... 14 5-3 Frequency-scan results in 910 MPa YS steel in seawater environment ............... 15 5-4 Frequency-scan results in 924 MPa YS steel in seawater environment ............... 15 5-5 Frequency-scan results in 945 MPa YS steel in seawater environment ............... 16 5-6 Frequency-scan results in 1080 MPa YS steel in seawater environment ............. Summary of frequency response in seawater versus steel yield strength (YS) .... 17 5-8 Frequency-scan results in 848 MPa YS steel in sour brine environment ............. 18 5-9 Frequency-scan results in 924 MPa YS steel in sour brine environment ............. 18 5-10 Frequency-scan results in 945 MPa YS steel in sour brine environment ............. 19 5-11 Summary of frequency response in sour brine versus steel yield strength (YS) ........................................................................................................................ 19 5-12 The effect of frequency schedule on the seawater corrosion-fatigue crack growth rates in the 848 MPa YS steel ................................................................... 22 5-13 The effect of frequency schedule on the seawater corrosion-fatigue crack growth rates in the 910 MPa YS steel ................................................................... 23 xi LIST OF FIGURES (Continued)14 Theeffect of frequency schedule on the seawater corrosion-fatigue crack growth rates in the 924 MPa YS steel ................................................................... 23 5-15 The effect of frequency schedule on the seawater corrosion-fatigue crack growth rates in the 945 MPa YS steel ................................................................... 25 5-16 The relative K-independence of seawater corrosion-fatigue crack growth rate in the 1080 MPa YS steel ............................................................................... 27 5-17 The effect of frequency schedule on the sour brine corrosion-fatigue crack growth rates in the 848 MPa YS steel ................................................................... 28 5-18 The effect of frequency schedule on the seawater corrosion-fatigue crack growth rates in the 945 MPa YS steel ................................................................... 29 5-19 Influence of frequency on crack growth in an aqueous H 2 S + CO 2 environment [8, 9] ................................................................................................ 30 5-20 Variation in crack closure and effective crack-driving force over time for experiments conducted in aqueous H 2 S + CO 2 environment at various cyclic frequencies [8, 9] .................................................................................................. 31 5-21 Notional representation of complex dependence of fatigue crack growth rates on cyclic frequency hypothesized based on current understanding of crack closure associated with corrosion-product induced wedging .................…”

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Corrosion-Fatigue Performance of High-Strength Riser Steels in Seawater and Sour Brine Environments

Hudak

Robledo

Hawk

2011

Volume 3: Materials Technology; Jan Vugts Symposium on Design Methodology of Offshore Structures; Jo Pinkster Symposium on Seco

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Although new high-strength steels have recently been developed to meet the demands of increased reservoir pressures, and sour production fluids, the corrosion-fatigue performance of these new higher-strength materials is largely unknown. The goal of this study was to fill this knowledge gap by generating corrosion-fatigue data in two aggressive environments: 1) a sour production brine, and 2) seawater with cathodic protection. The focus of the current paper is on stress-life (S-N) corrosion-fatigue results in these environments, as well as a baseline air environment. Experiments were performed on five different steels with yield strengths ranging from 848 MPa to 1080 MPa. Prior frequency-scan results based on corrosion-fatigue crack growth rate data demonstrated that not all of these material-environment combinations exhibit a saturation frequency where the detrimental environmental effect approached a constant value as the cyclic loading frequency is decreased. Consequently, S-N tests were performed at different frequencies (0.01 Hz, 0.17 Hz, and 1 Hz), depending on the fatigue life regime, in attempting to match the loading frequencies experienced in service. Corrosion-fatigue occurred at stresses well below the fatigue endurance limit in laboratory air, and cyclic lives in the seawater with cathodic protection environment were found to be 2X to 10X less than those in the baseline air environment, while cyclic lives in the sour brine environment were found to be 30X to 100X less than those in the baseline air environment. In both environments, degradation was greatest at lower stresses in the high cycle fatigue regime. The effect of material strength level had little or no measurable effect on the S-N corrosion-fatigue performance, and the effect of cyclic frequency on the corrosion-fatigue performance was mixed. The S-N response to these two variables differed significantly from recently measured fatigue crack growth kinetics in these same materials that were performed in a companion study. Possible reasons for these differences are discussed.

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Titanium Drilling Risers—Application and Qualification

Cited by 11 publications

References 3 publications

Design Consideration for Composite Drilling Riser

Design Consideration for Composite Drilling Riser

Mechanical Drilling Processes for Titanium Alloys: A Literature Review

Corrosion-Fatigue Performance of High-Strength Riser Steels in Seawater and Sour Brine Environments

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