Cement Designs for High-Rate Acid Gas Injection Wells

Abstract

High rate acid gas injection wells pose a significant challenge for the design of cementing systems. CO2 conversion of Portland cement to calcium carbonate is a significant problem. This paper describes the design and use of two cement systems for high rate acid gas injection wells. The paper compares risks and benefits of a high alumina cement slurry to those of a specialty Portland based system. Case history reviews of the application of both systems on liner cement jobs are detailed. The systems were used on wells designed for a 65% H2S, 35% CO2 injection stream at a rate of 65 million scf/day. High alumina cement is used in many applications to address the problem of CO2 conversion of Portland cement. The cement is resistant to CO2, but high temperature fluid loss control was not available, preventing its application on long liners. Lack of an effective high temperature fluid loss additive required the development of an alternate Portland based system. Later development of an effective high temperature fluid loss additive ultimately allowed use of the high alumina cement system. A CO2 resistant Portland system was developed by limiting the cement concentration and reducing total system permeability by use of specialty sized particles. This paper discusses the development and testing of a Portland based cement system and the associated risks with the use of this specialty system. Quality control steps to address the complex blending process and steps taken to improve system reliability are presented. Background Two acid gas injection wells (AGI 3–14 and 2–18) were drilled in the western United States as part of an overall gas plant de-bottlenecking. Plant throughput capacity was being increased by converting the plant to acid gas disposal by injection. The anticipated waste gas stream was 65% H2S and 35% CO2, with the design volume for the wells being based on the capacity of the plant plus adequate backup.

A review on cement degradation under CO 2 -rich environment of sequestration projects

“…iii. Using Non-Portland cements (Benge, 2005). Non-Portland cement is not generally recommended though because of its unavailability and cost (Benge, 2009).…”

“…A precautionary note was given in selecting the elastomer, as excessive swelling may cause stress and lead to cracks in the cement. It was also recommended to use latex as one of the procurement methods for resisting CO 2 attack (Bai et al, 2015;Shahval et al, 2014;Benge, 2005). According to recent studies, adding latex in the cement structure improves the bonding strength, controls the filtration loss and allows good strength in the hardened cement paste.…”

Types of Permanent Plugging Materials

“…Compared to Portland cement, these types of cements are low in silica content [5]. The calcium aluminate cements have high resistance to corrosive environments, rapid hardening properties, and are stable at high temperatures [15]. Addition of Portland cement to calcium aluminate cements results in flash setting.…”

Presença De Co2 Em Projetos De Desenvolvimento De Campos De Petróleo: Arcabouço Teórico E Estudo De Caso

“…As equações abaixo descrevem estas etapas:(i) CO 2 + H 2 O  H 2 CO 3 (ii) H 2 CO 3 + Ca(OH) 2  CaCO 3 (iii) C-S-H + H 2 CO 3  CaCO 3 + sílicaO processo continua com o carbonato de cálcio reagindo com ácido carbônico, levando a formação de bicarbonato de cálcio (Ca(HC 3 ) 2 ), que por sua vez reage com o cimento, levando à formação de mais CaCO 3 e H 2 O. A contínua presença de água permite que mais ácido seja gerado, em uma reação em cadeia(BENGE, 2005). (iv) CaCO 3 + H 2 CO 3  Ca(HC 3 ) 2 (v) Ca(HC 3 ) 2 + Ca(OH) 2  2 CaCO 3 + H 2 O Como a reação do CO 2 com cimento é termodinamicamente favorável, a mesma não pode ser integralmente prevenida.…”