Performance of Oilwell Cementing Compositions in Geothermal Wells

Gallus, J.P.; Watters, Larry; Pyle, D. E.

doi:10.2118/7591-pa

Cited by 12 publications

(2 citation statements)

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“…This was confirmed by the natural CO 2 producer [ 9 ] and by pilot storage wells [ 10 ] that proved to operate without issues for extended periods of time. Cement sample well exposure tests also confirmed the OPC/silica HT blend to be stable for extended periods of time at temperatures below 200 °C [ 11 ]. In this study, formulations with higher silica content were shown to be preferential for good mechanical performance and lower porosity of cement after up to a year of field exposure.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Cementitious Composites for High-Temperature Geothermal Wells

Pyatina,

Sugama,

Moghadam

et al. 2024

Materials

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High-temperature (HT) geothermal wells can provide green power 24 hours a day, 7 days a week. Under harsh environmental and operational conditions, the long-term durability requirements of such wells require special cementitious composites for well construction. This paper reports a comprehensive assessment of geothermal cement composites in cyclic pressure function laboratory tests and field exposures in an HT geothermal well (300–350 °C), as well as a numerical model to complement the experimental results. Performances of calcium–aluminate cement (CAC)-based composites and calcium-free cement were compared against the reference ordinary Portland cement (OPC)/silica blend. The stability and degradation of the tested materials were characterized by crystalline composition, thermo-gravimetric and elemental analyses, morphological studies, water-fillable porosity, and mechanical property measurements. All CAC-based formulations outperformed the reference blend both in the function and exposure tests. The reference OPC/silica lost its mechanical properties during the 9-month well exposure through extensive HT carbonation, while the properties of the CAC-based blends improved over that period. The Modified Cam-Clay (MCC) plasticity parameters of several HT cement formulations were extracted from triaxial and Brazilian tests and verified against the experimental results of function cyclic tests. These parameters can be used in well integrity models to predict the field-scale behavior of the cement sheath under geothermal well conditions.

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Section: Introductionmentioning

confidence: 99%

Assessment of Cementitious Composites for High-Temperature Geothermal Wells

Pyatina,

Sugama,

Moghadam

et al. 2024

Materials

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“…The high temperatures pose challenges while the well is being drilled and completed and after construction has been completed. [1][2][3] In a geothermal well, carbon dioxide (CO 2 ) may be encountered in some of the formations, which can be a serious corrosive threat to both the cement and the casing in the well.…”

Section: Introductionmentioning

confidence: 99%

High-Temperature Wells With Lost-Circulation Demands and Reverse-Circulation Techniques Using Foamed-Cement Systems: Two Case Histories

Moore¹,

Bour

Reed

et al. 2005

SPE Drilling &Amp; Completion

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Drilling activities in diverse areas can pose significant challenges for conventional cement systems and circulation methods. To overcome these challenges, a unique cementing system and a circulation method have been tested in the field with great success. This paper details how these technologies and techniques were successfully used in the cementation process of one casing string in a relatively shallow geothermal well in central California and a relatively deep string in central Wyoming.Globally, many wells experience lost-circulation problems that require the reduction of circulation pressures to allow proper placement of cement to provide annular coverage. To help minimize these circulation pressures, cement was directly pumped into the annulus, significantly reducing placement pressures and allowing placement of the cement with no apparent losses-a process referred to as the reverse-circulation placement technique (RCPT). In the deep and shallow applications discussed, the placement technique and the individual slurry designs address temperature issues.

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