Detecting Ultra-small Leaks With Ultrasonic Leak Detection-Case Histories
From the North Slope, Alaska

Julian, Jennifer Yvonne; King, G.E.; Johns, Joel E.; Sack, Janet; Robertson, Daniel

doi:10.2523/108906-ms

Cited by 5 publications

(2 citation statements)

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“…Before the ultrasonic log, the general belief was that multiple thread leaks in the tubing caused slow tubing-to-annulus communication in WAG injectors (Julian et al, 2007). The completion included nine gas lift mandrels with dummy valves.…”

Section: Figure 15 -Example Of Borax-pnl Log Run On Injection Well Fimentioning

confidence: 99%

Well Integrity Technical and Regulatory Considerations for CO2 Injection Wells

Syed

Cutler²

2010

All Days

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Geologic carbon sequestration may involve injection of large quantities of carbon dioxide (CO 2 ) into primarily deep saline aquifers for storage purposes or, where feasible, into oil and gas reservoirs for enhanced oil recovery objectives. The literature and experience from industrial analogs indicates that well-bores (active or inactive/abandoned) may represent the most likely route for leakage of injected CO 2 from the storage reservoirs. Therefore, sound CO 2 injection well design and well integrity, operation and monitoring are of critical importance in such projects. This paper presents design considerations for (1) the construction of CO 2 injection wells including down-hole tubular (casing/tubing/packer) and cements, (2) methods to verify that the wells have mechanical integrity (both internal and external) and monitoring approaches applicable to CO 2 geo-sequestration in the U.S. and a short discussion of the risks posed by abandoned wells within a storage field and the safety aspect of CO 2 wells.

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Section: Figure 15 -Example Of Borax-pnl Log Run On Injection Well Fimentioning

confidence: 99%

Well Integrity Technical and Regulatory Considerations for CO2 Injection Wells

Syed

Cutler²

2010

All Days

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“…In addition, an ultrasonic leak detection logging tool was introduced to detect very small leaks and also it can be used to determine the leaks in the production tubing and outside the pipe (Julian et al 2007a). Johns (2007b) presented an ultrasonic leak detection method to locate small leaks behind the tubing and in casing as well. This method is based on ultrasonic signature and/or an audible signature.…”

Section: Literature Reviewmentioning

confidence: 99%

A numerical method to predict crossflow rate resulted from downhole leaks

Al-Hajri

Al-Ajmi

Mahmoud

2018

J Petrol Explor Prod Technol

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Water injection wells often develop casing leaks that result in crossflow between two formations. The crossflow can be upward or downward depending on the respective location of each formation and the gravitation hydrostatic column between the formations. Traditionally, crossflow rates are measured by running production logs (flowmeter); a process that require well intervention. Such intervention in a well with compromised downhole integrity is not preferred as it incur additional cost and exposes the oilfield operator to possible mechanical risks such as stuck tools. In this work, we present a numerical method to predict crossflow rates without such intervention. The method requires readily available input from the water injection that includes injection flow rates and pressures, in addition, to shut-in well data. The workflow developed in this study includes nodal analysis and well performance modeling. A water injection well (Well-XYZ) was selected to validate the developed workflow as a case study in this paper. Well-XYZ has an upward crossflow that resulted from a downhole leak. The numerical method starts with building a well performance model before the leak develops. The injection data (pressure and flow rates) before leak development are used for this model. Second, a well with the same physical dimensions of Well-XYZ is imagined and modeled as a producing well from the downhole formation to the leak point. The shut-in well data of Well-XYZ are used to build the production well model. Third, we choose the leak point as the system node and obtain its pressure either by direct measurement or through calculation. Once the system node pressure is obtained, it is inputted as the wellhead producing pressure of the imagined well and its production rate will be the crossflow rate. The results of this method were tested by running a production log on Well-XYZ. The results of the production log showed that the method was able to accurately predict the crossflow rate with a less than 2% error. Keywords Downhole leaks · Crossflow · Nodal analysis · Well performance · Water injection List of symbols

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