Time-dependent wellbore instability and ballooning in naturally fractured formations

Helstrup, Ole A.; Chen, Zhixi; Rahman, Sheik S.

doi:10.1016/j.petrol.2004.01.001

Cited by 23 publications

(8 citation statements)

References 14 publications

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“…was pumped down the hole to plug the permeable zones. However, the resulting reduction in mud Within three of these Corona Ridge wells which encountered drilling fluid losses through the Balder Formation (213/26-1, Rosebank Main; 214/4-1, Tobermory; 214/9-1, Bunnehaven), the lost drilling fluid later returned to the wellbore in a process called wellbore ballooning (Helstrup et al 2004). Ballooning can be problematic as returning drilling fluid can be interpreted wrongly as an influx of formation fluid (known as a "kick").…”

Section: Drilling Fluid Losses and Gains (Ballooning)mentioning

confidence: 99%

Raiders of the Lost Mud: the geology behind drilling incidents within the Balder Formation around the Corona Ridge, West of Shetland

Watson

Schofield

Maguire

et al. 2019

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The Faroe-Shetland Basin, NE Atlantic continental margin, hosts a number of important hydrocarbon fields, though deep water and narrow weather windows mean drilling costs are considerably higher than other parts of the UK Continental Shelf. Any additional drilling complications are therefore important to predict and negate as such issues can result in avoidable multi-million pound cost implications. This study focuses on the Corona Ridge, an intra-basinal high which contains the Rosebank Field, where a plethora of drilling issues, of enigmatic origin, are common within a key stratigraphic marker known as the Balder Formation. Drilling fluid loss, bit balling, wellbore breakouts, and wellbore "ballooning", where lost drilling fluid returns to the wellbore, are all recognised within the Balder Formation along the Corona Ridge. We find that many of the drilling incidents can be traced back to both the lithological character of the Balder Formation, and the mid-Miocene tectonic inversion of the Corona Ridge. Moreover, we find that this geological explanation has wider implications for exploration in the region, including mitigation of drilling incidents in future wells through drill bit selection.The Faroe-Shetland Basin, located on the NE Atlantic continental margin, represents one of the last remaining exploration frontiers of the UK Continental Shelf, with arguably the greatest remaining potential for significant new discoveries (Ellis & Stoker 2014;Austin et al. 2014). One particularly prospective area of the Faroe-Shetland Basin is the Corona Ridge (Fig. 1), an intra-basinal high which hosts a number of oil and gas discoveries, notably the ~240 million barrels of oil equivalent Rosebank Field (Austin et al. 2014). A challenging aspect of exploring around the Corona Ridge area, though, is high drilling costs associated with deep water (up to 1.5 km in places) and extreme weather conditions (Austin et al. 2014), necessitating the use of either fifth generation semi-submersible drill rigs ($125,000/day) or dynamically positioned drillships ($145,000/day) (IHS Markit 2018) in order to drill exploration and appraisal wells. Further exploration costs result from a myriad of drilling complications, particularly through thick volcanic sequences. Previous research has focused on drilling efficiency through these volcanic sequences, emphasising how key lithological properties contribute to different drilling and well control issues (

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Section: Drilling Fluid Losses and Gains (Ballooning)mentioning

confidence: 99%

Raiders of the Lost Mud: the geology behind drilling incidents within the Balder Formation around the Corona Ridge, West of Shetland

Watson

Schofield

Maguire

et al. 2019

View full text Add to dashboard Cite

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“…Wellbore stability is mainly studied from the three aspects of mechanics, chemistry, and multiphysical coupling. Mechanical research studies the stress distribution around the wellbore and the influence of anisotropy on wellbore stability from the perspective of mechanical energy [1][2][3][4]. Chemical research studies the influence of hydration of drilling fluid filtration and shale on the rock strength from the perspective of chemical energy, which leads to borehole wall falling or collapse [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Application of Configuration Force to Dynamic Crack of Shale under Hydration

Fan

Zhao

et al. 2021

Mathematical Problems in Engineering

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The natural microdefects of shale and the expansion of microcracks under hydration and overlying rock loadings are important for the wellbore stability. According to the conservation of energy, the force of the microdefects and microcracks under finite deformation is studied by the method of configuration force through the migrating control volume in the spatial observer. Under the hydration stress and rock pressure, the equation of hydration stress and its work in reference configuration has been obtained, and the equations of configuration forces and configuration moment have been established as a consequence of invariance under changes. The relationship between the configuration and deformation forces is determined by the second law. The energy dissipation equation of the crack tip has been deduced, which shows that the projection of the concentrated internal configuration body force at the crack tip in the opposite direction of the crack is equal to the energy dissipation of the crack tip per unit length. The inertial and internal parts of the concentrated configuration body force at the crack tip have been derived; it is indicated that the internal configuration force plays a leading role in the irreversible fracture process. Moreover, the energy release rate of shale under hydration is proved to depend on constitutive responses and hydration stress. In the theoretical system of configuration force, the migrating control volume at the crack tip contains inclusions, microcracks, microvoids, and heterogeneity of the rock itself. We use the configuration force theory to solve the problem of rock crack propagation and rock fracture. The factors considered are more comprehensive, which can better reflect the actual situation and provide a theoretical basis for the study of wellbore stability.

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“…In the process of drilling, the economic losses caused by wellbore instability reaches more than one billion dollar every year [11], and the lost time is accounting for over 40% of all drilling related nonproductive time [12]. It is also reported that shale account for 75% of all formations drilled by the oil and gas industry, and 90% of wellbore stability problems occur in shale formations [13–18]. When a well is drilled, the formation around the wellbore must sustain the load that was previously taken by the removed formation.…”

Section: Introductionmentioning

confidence: 99%

Wellbore Stability in Oil and Gas Drilling with Chemical‐Mechanical Coupling

Yan

Deng

2013

The Scientific World Journal

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Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced. The diffusion coefficient of shale hydration is measured with the downhole temperature and pressure condition, then the penetration migrate law of drilling fluid filtrate around the wellbore is calculated. Furthermore, the changing rules of shale mechanical properties affected by hydration and water absorption are studied through experiments. The relationships between shale mechanical parameters and the water content are established. The wellbore stability model chemical-mechanical coupling is obtained based on the experimental results. Under the action of drilling fluid, hydration makes the shale formation softened and produced the swelling strain after drilling. This will lead to the collapse pressure increases after drilling. The study results provide a reference for studying hydration collapse period of shale.

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Time-dependent wellbore instability and ballooning in naturally fractured formations

Cited by 23 publications

References 14 publications

Raiders of the Lost Mud: the geology behind drilling incidents within the Balder Formation around the Corona Ridge, West of Shetland

Raiders of the Lost Mud: the geology behind drilling incidents within the Balder Formation around the Corona Ridge, West of Shetland

Application of Configuration Force to Dynamic Crack of Shale under Hydration

Wellbore Stability in Oil and Gas Drilling with Chemical‐Mechanical Coupling

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