Portal de Periódicos da CAPES

Innovative Remedial Cementing Solution Provides Annular Isolation in Duyong B-4

2006; Volume: 21; Issue: 01 Linguagem: Inglês

10.2118/88017-pa

1930-0204

Thomas Morris, M. Zuki Bidi, Youssef Elmarsafawi, Devan Nair, Rifat Said, Reha Tugcu, Jane Ong,

Reservoir Engineering and Simulation Methods

Summary Whether a cement-squeeze operation results in an annular seal depends heavily on how far the cement can penetrate and disperse in the fine channels of a partially cemented annulus. In many cases, a conventional- or microfine-cement slurry will dehydrate and bridge off before it can achieve its objectives (Nelson et al. 1990). This paper describes the use of an engineered, optimized slurry for a squeeze operation in the Duyong B-4 well, which had a perforated zone that demonstrated a low rate of seawater injectivity. This paper also presents the slurry design and properties, execution procedure, and prejob and post-job log evaluations. After several years of production, gas bubbles appeared in various locations throughout the Duyong field. Shallow seismic readings showed gas charging in several shallow gas layers throughout the Duyong field. Several wells were investigated as possible contributors to the charging of the shallow sandstone layers, and Duyong B-4 was selected as a probable contributor. Duyong B-4 is a gas well that was completed in November 1983 with four producing zones. In September 2003, this well was selected as a test well to evaluate the cement quality behind the casing. Both cement-bond logs and ultrasonic-imaging logs showed gas and fluid channels behind the casing. An optimized cement slurry (OCS) was engineered and tested in the laboratory under well conditions. Results showed excellent penetration in narrow gaps, optimum fluid-loss control, and low rheology, both at surface and downhole conditions. The slurry was used in the squeeze operation; post-job logs demonstrated the success of the treatment. The slurry penetrated the narrow gaps without dehydrating, and good mechanical properties were achieved in short setting times (Moulin et al. 1997). These properties are especially important in gas-producing wells, and they met all the objectives set forth by the client.