Stochastic modelling of wellbore leakage in British Columbia

Trudel, E.; Frigaard, I.A.

doi:10.1016/j.petrol.2022.111199

Cited by 8 publications

(9 citation statements)

References 36 publications

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“…Wellbore leakage (SCVF/GM) is a complex process with many possible, yet poorly understood, drivers. , For example, poor curing/installation of wellbore cement can result in permanent fluid transmission pathways for SCVF/GM; ,− production type, geography, and geology may influence emissions; ,− and well casing/cement degradation can result in issues that develop over time. , GM study is further complicated since gas may not be emitted uniformly around a wellhead, if at all. − Perhaps because of these complexities, well integrity tracking in Canada has largely relied on periodic testing.…”

Section: Methodsmentioning

confidence: 99%

Highly Uncertain Methane Leakage from Oil and Gas Wells in Canada Despite Measurement and Reporting

Seymour,

Xie,

Kang

2024

Energy Fuels

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Leakage of fluids from oil and gas wells is a source of the key greenhouse gas methane, and presents environmental risks, including groundwater contamination. A loss of well integrity can result in fluid leakage into the annular space between subsequent well casings (which is often vented to the atmosphere) or into the surrounding subsurface. In Canada, industry reporting on well integrity is often incomplete, leading government inventories to disagree on emission magnitudes. In this study, we model wellbore methane emissions using industry data in British Columbia and Alberta, Canada, finding that differing model assumptions to handle unclear/missing data have a strong influence on estimated emissions. Considering estimates derived from industry reporting and from independent measurement, wellbore emissions in the two provinces range anywhere from 23 to 176 kt of methane, representing 1.7−11.4% of their upstream sector methane emissions. Further, finding over 130 examples of measured leaks seemingly missing from industry reporting, we conclude that wellbore emissions, groundwater contamination, and broader environmental risks are underestimated. We provide recommendations to improve well integrity tracking through data quality assurance measures and increased testing. Finally, we find that ongoing optical gas imaging camera surveys could be an effective tool to augment wellbore testing requirements to minimize industry burden.

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Section: Methodsmentioning

confidence: 99%

Highly Uncertain Methane Leakage from Oil and Gas Wells in Canada Despite Measurement and Reporting

Seymour,

Xie,

Kang

2024

Energy Fuels

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“…Results from experimental studies thus point to microannuli being highly varied in the azimuthal direction but presenting some continuity in the well axis direction and with microannulus thicknesses ranging from 0 to upwards of 200µm. Taking these basic features Trudel and Frigaard [18] derived a probabilistic model for microannulus thickness along sections of well. The base model parameters were calibrated against the distribution of well leakage data collected from over 3000 wells.…”

Section: Aquifermentioning

confidence: 99%

“…Our study is mostly focused on the establishment of a viable method for assessing the effectiveness of squeeze cementing operations, which depends on the degree of blockage of the microannulus after the cement slurry has been pumped. To do this we select the microannulus thickness using a stochastic model based on [18]; see §3.2. We use the geometry to study two types of invasion problem in this paper: a planar invasion and a radial (perforation squeeze) invasion.…”

Section: Model Parameters and Scope Of Studymentioning

confidence: 99%

“…The distribution of microannulus thickness one might encounter is best described using right-skewed distributions as detailed by [16]. Based on these observations, in [18] we developed a stochastic model for microannulus thickness variation and calibrated the model against BC wellbore leakage data. We describe this model below.…”

Section: Micro-annulus Modelmentioning

confidence: 99%

“…stronger variations azimuthally than axially, is controlled by selecting m x m y . In [18] each microannulus geometry is used in a leakage model based on the typical parameters of a BC well, resulting in computation of a leakage rate; an example is given in Fig. 5.…”

Section: Micro-annulus Modelmentioning

confidence: 99%

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