Abstract

Cement plugs are a widely used well intervention method to achieve zonal isolation and well plug and abandonment. The current practice of cementing using wireline was reviewed on a system level to identify the primary challenges. Existing cement mix properties, such as compressive strength and wait-on-cement (WOC) time, were characterized using standard API RP 10B-2 (2013) tests. The sensitivity of these mixes to various wellbore temperature and pressure conditions was also studied. Based on the understanding of the current practice, modifications of the compositions, packaging, and mixing procedures in the field were proposed and tested accordingly. Based on the experimental results, the properties of the current cement mixes showed high sensitivity to temperature variations as small as 10°F. To achieve a cement plug as expected, accurate knowledge of the well temperature profile and precise selection of the best additives for such small temperature intervals are necessary. If crossflow occurs, then setting a plug itself can change the temperature profile. This makes cement plug operations even more challenging during actual field practice. The cement mixes were modified and tailored to reduce their sensitivity to temperature without affecting the dump time and strength development. This paper discusses the challenges associated with wireline-run cementing operations and presents a simple and streamlined process developed to help reduce operational time and minimize costs. The study also discusses cement mixes customized for dump bailer operations.

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