Coiled Tubing in High-Pressure Wells

Newman, K.R.; Allcorn, Marc

doi:10.2118/24793-ms

Cited by 4 publications

(1 citation statement)

References 6 publications

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“…If the compressive load on the CT increases too much, it causes catastrophically buckle in this unsupported interval. 1 Y Yang 2 studied the failure of straight tubing under the outer diameter pressure and found a relationship between the collapsed compressive stress and the tensile force. K Newman et al 3 used the equation from Gordon-Rankine and obtained the buckling load of the CT, but he assumed that the CT is straight.…”

Section: Introductionmentioning

confidence: 99%

Buckling load of bending coiled tubing under an injector

Zhu

Zheng

Hao³

2018

Advances in Mechanical Engineering

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When coiled tubing is applied in high oil-gas wells, buckling load of a coiled tubing under the injector is the key for functionality. The coiled tubing is curved, but it is simplified to straight tubing for buckling load solved in the past. These calculations were not sufficient for the problem. In this article, buckling load of a bent coiled tubing is discussed based on the actual details of the exploitation. First, the coiled tubing curvature changes during the working period reaching the shape presented in analysis of the article. To determine the distribution of stress and the zones to failure, a coiled tubing was studied using the theory of curved beam moment, and buckling load of the bending coiled tubing was derived. The study has indicated that the gooseneck curve radius and the yield strength enable to determine the residual curvature of coiled tubing. The axial stress along the convex and concave sides is a half periodic sine and cosine distribution along the length of the coiled tubing, and the maximum axial stress is on the middle of the concave side of the outside diameter of the coiled tubing. There is an inversely proportional relationship between buckling load and length of the tubing, and a proportion of buckling load and the diameter-thickness ratio. Moreover, buckling load was more sensitive to the tubing length than its wall-thickness.

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Section: Introductionmentioning

confidence: 99%

Buckling load of bending coiled tubing under an injector

Zhu

Zheng

Hao³

2018

Advances in Mechanical Engineering

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Application of Velocity String to Improve Productivity from Bottom pays after Hydraulic Fracturing in Multilayered Low Permeability Reservoir

Anand¹,

Johri²,

Chandak³

et al. 2018

IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition

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Raageshwari gas field is located in RJ-ON 90/1 Block in western India with Cairn Oil & Gas, a vertical of Vedanta Limited as operator of the field. Multistage hydraulic fracturing is required to achieve commercial production from the highly laminated retrograde gas condensate reservoir. It has been observed in almost all wells that the top high PI zones produce a majority of the gas. The wells have a water column across bottom few fracs which prohibits production from these zones. Water unloading through increased drawdown was not successful because of higher PI of the upper fracs. Coiled tubing-based nitrogen lift of the water column is not commercially feasible. It is important to find a low-cost solution for water unloading since bottom zones account for approximately 30% of total gas in place. A solution has been developed using a customized velocity string design, which can unload the water while maintaining high well production. Conventional velocity strings are only installed in late life of gas wells when liquid loading is observed. These conventional designs limit the maximum rate to 2-3 MMSCFD and therefore cannot be used in Raageshwari gas field for water unloading as high individual well rates (8 to 12 MMSCFD) is required to meet field plateau production. After reviewing various options, an innovative and unique velocity string system design was developed which incorporates a customized surface spool and string hanging system. This customized design allows combined or independent gas flow conduits as described below: Through the annulus of velocity string and tubing when higher gas rates are required. Through the velocity string to facilitate liquid unloading due to high gas velocity. Production from both the conduits to meet higher demands than the annulus flow alone. Well integrity was assured by maintaining two independent barriers during commissioning, production phase and also during future string retrieval. This paper will discuss in detail the design considerations of the velocity string and surface hanger system to achieve liquid unloading while maintaining high rate gas production. It will also have details on the dual barrier selection process and the design customization that have been done to ensure cyclic liquid unloading and high rate gas production. This innovative velocity string design is technically a dual completion with a much lower cost and footprint. The same design can be implemented across a wide variety of applications to address well integrity issues, selective zonal production etc. The application of this design in Raageshwari field will ensure planned recovery of gas from the field and will also support plateau production phase. This design can be an efficient and economic technique to develop similar fields.

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Collapse Pressure of Oval Coiled Tubing

Newman

1992

European Petroleum Conference

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This paper was selected for presentation by an SPE Program Committee following review of information contained in an abstract submitted by the author@). Contents of the paper. as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author@). The material, as presented, does not necessarily reflect any positlon of the Society of Petroleum Engineers, its officers, or members. Papers presented at SPE meetings are subject to publication review by Editorial Committees of the Society of Petroleum Engineers. Permission to copy is restricted to an abstmct of not more than 300 words. Illustrations may not be copied. The a b s t r a c t s of where and by whom the paper is presented.

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Coiled Tubing in High-Pressure Wells

Cited by 4 publications

References 6 publications

Buckling load of bending coiled tubing under an injector

Buckling load of bending coiled tubing under an injector

Application of Velocity String to Improve Productivity from Bottom pays after Hydraulic Fracturing in Multilayered Low Permeability Reservoir

Collapse Pressure of Oval Coiled Tubing

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