Coiled tubing

Novel Approach Removes Scale Contaminated With Naturally Occurring Radioactive Material

This paper describes a case history in the UAE in which the cleanout of scale contaminated with naturally occurring radioactive material was conducted successfully.

Fig. 1—PPE used included radiation protection such as lead glass, lead apron, lead gloves, half facemask with Rd90 ABEK Filter 3 cartridge, and NORM personal dosimeter.
Fig. 1—PPE used included radiation protection such as lead glass, lead apron, lead gloves, half facemask with Rd90 ABEK Filter 3 cartridge, and NORM personal dosimeter.
Source: SPE 220493.

Upper Zakum is one of the largest offshore oil fields in the world, approximately 80 km offshore Abu Dhabi. One of its developmental challenges is its shallow depth of 5–15 m, which makes conventional drilling and production platforms impractical and costly. The operator has created four artificial islands to serve as bases for drilling and production facilities. The islands are designed to minimize environmental impact, maximize oil recovery, and reduce operational costs.

Overview of Radioactive Scales in Oil and Gas

Generation and Nature of Naturally Occurring Radioactive Material (NORM). The cause of the formation of NORM as scale adhering to equipment and tubulars is water-soluble radiochemical compounds that occur naturally in the geological formation of the hydrocarbon reservoir and are transferred through the system together with the produced water, where they form commonly less-soluble compounds and precipitate as a mineral scale under certain chemical, mechanical, and thermodynamic conditions.

The primary radioisotopes of concern in oil and gas industry NORM, forming the metal part of this scale, are related to the uranium/radium decay series and the thorium/radium decay series but also to potassium-40; these occur freely in the Earth’s crust.

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