Well-Integrity Issues Offshore Norway

Vignes, Birgit; Aadnøy, Bernt S.

doi:10.2118/112535-pa

Cited by 30 publications

(4 citation statements)

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“…Casing leaks can occur through faulty pipe joints, corrosion, or mechanical failure due to thermal stresses or overpressuring (52). Vignes & Aadnøy (63) found that leaks through steel tubing and casing accounted for most failures in offshore Norway. Schwind et al (64) observed that 90% of casing failures were attributable to faulty connections.…”

Section: Mechanisms Of Wellbore-integrity Failurementioning

confidence: 99%

The Environmental Costs and Benefits of Fracking

Jackson

Vengosh

Carey

et al. 2014

Annu. Rev. Environ. Resour.

376

203

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Unconventional oil and natural gas extraction enabled by horizontal drilling and hydraulic fracturing (fracking) is driving an economic boom, with consequences described from "revolutionary" to "disastrous." Reality lies somewhere in between. Unconventional energy generates income and, done well, can reduce air pollution and even water use compared with other fossil fuels. Alternatively, it could slow the adoption of renewables and, done poorly, release toxic chemicals into water and air. Primary threats to water resources include surface spills, wastewater disposal, and drinking-water contamination through poor well integrity. An increase in volatile organic compounds and air toxics locally are potential health threats, but the switch from coal to natural gas for electricity generation will reduce sulfur, nitrogen, mercury, and particulate air pollution. Data gaps are particularly evident for human health studies, for the question of whether natural gas will displace coal compared with renewables, and for decadal-scale legacy issues of well leakage and plugging and abandonment practices. include data for (a) estimated ultimate recovery (EUR) of unconventional hydrocarbons, (b) the potential for further reductions of water requirements and chemical toxicity, (c) whether unconventional resource development alters the frequency of well integrity failures, (d ) potential contamination of surface and ground waters from drilling and spills, (e) factors that could cause wastewater injection to generate large earthquakes, and ( f ) the consequences of greenhouse gases and air pollution on ecosystems and human health.

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Section: Mechanisms Of Wellbore-integrity Failurementioning

confidence: 99%

The Environmental Costs and Benefits of Fracking

Jackson

Vengosh

Carey

et al. 2014

Annu. Rev. Environ. Resour.

376

203

View full text Add to dashboard Cite

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“…Erno and Schmitz [1996], for example, reported that 22% of 435 abandoned wells monitored between 1987 and 1993 in Saskatchewan, Canada, were leaking because of well integrity failure. Elsewhere, the Norwegian Petroleum Safety Authority (PSA) has reported that 15% of 323 production wells, and 33% of 83 injection wells drilled between 1970 and 2006 on the Norwegian Continental Shelf (NCS) had some kind of well integrity problem (related to tubing, annulus safety valves, casing or cement), while 7% of these wells had to be shut-in (closed) due to well integrity issues [Vignes and Aadnøy, 2010]. In a more recent investigation, Davies et al [2014] reported that 6.3% of 8030 wells drilled between 1958 and 2013 in the Marcellus shale of Pennsylvania in the northeast United States showed well integrity and barrier failure and 1.3% of these wells were leaking to surface.…”

Section: Water Resources Researchmentioning

confidence: 99%

Numerical investigation of methane and formation fluid leakage along the casing of a decommissioned shale gas well

Nowamooz

Lemieux

Molson

et al. 2015

Water Resources Research

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Methane and brine leakage rates and associated time scales along the cemented casing of a hypothetical decommissioned shale gas well have been assessed with a multiphase flow and multicomponent numerical model. The conceptual model used for the simulations assumes that the target shale formation is 200 m thick, overlain by a 750 m thick caprock, which is in turn overlain by a 50 m thick surficial sand aquifer, the 1000 m geological sequence being intersected by a fully penetrating borehole. This succession of geological units is representative of the region targeted for shale gas exploration in the St. Lawrence Lowlands (Qu ebec, Canada). The simulations aimed at assessing the impact of well casing cementation quality on methane and brine leakage at the base of a surficial aquifer. The leakage of fluids can subsequently lead to the contamination of groundwater resources and/or, in the case of methane migration to ground surface, to an increase in greenhouse gas emissions. The minimum reported surface casing vent flow (measured at ground level) for shale gas wells in Quebec (0.01 m 3 /d) is used as a reference to evaluate the impact of well casing cementation quality on methane and brine migration. The simulations suggest that an adequately cemented borehole (with a casing annulus permeability k c 1 mD) can prevent methane and brine leakage over a time scale of up to 100 years. However, a poorly cemented borehole (k c ! 10 mD) could yield methane leakage rates at the base of an aquifer ranging from 0.04 m 3 /d to more than 100 m 3 /d, depending on the permeability of the target shale gas formation after abandonment and on the quantity of mobile gas in the formation. These values are compatible with surface casing vent flows reported for shale gas wells in the St. Lawrence Lowlands (Quebec, Canada). The simulated travel time of methane from the target shale formation to the surficial aquifer is between a few months and 30 years, depending on cementation quality and hydrodynamic properties of the casing annulus. Simulated longterm brine leakage rates after 100 years for poorly cemented boreholes are on the order of 10 25 m 3 /d (10 mL/d) to 10 23 m 3 /d (1 L/d). Based on scoping calculations with a well-mixed aquifer model, these rates are unlikely to have a major impact on groundwater quality in a confined aquifer since they would only increase the chloride concentration in a pristine aquifer to 1 mg/L, which is significantly below the commonly recommended aesthetic objective of 250 mg/L for chloride.

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“…With the development of deepwater drilling technology, wellbore integrity is increasingly under scrutiny. According to the survey of wellbore integrity conducted by Norwegian Petroleum Safety Authority (PSA) on 106 offshore wells with different development years and production categories, 18% of them had problems with wellbore integrity, and 7% of them were forced to close wells because of wellbore integrity, which caused significant environmental and economic losses. , In the process of deep-well testing and production, the high-temperature (HT) flow produced in the deepwater wells will cause additional pressure in casing annulus. If the axial force generated by excessive temperature change is greater than the bearing capacity of the shear pin at the wellhead, the wellhead will move up and seriously threaten wellbore integrity. − In Marlin oilfield in the Gulf of Mexico, excessive annular pressure during oil production resulted in the deformation and fracture of the casing and tubing of well A-2 few hours after production .…”

Section: Introductionmentioning

confidence: 99%

Influence of Cement Return Height on the Wellhead Uplift in Deep-Water High-Pressure–High-Temperature Wells

Zheng

2021

ACS Omega

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In oil and gas production in deep-water high-pressure−hightemperature (HP−HT) wells, wellhead uplift may cause the seal failure of wellbore integrity. Aiming at the oil and gas production stage in deep-water HP−HT wells, we considered the influence of cement sheath cementation and developed a model for calculating the height of wellhead uplifts, and simulation experiments for wellhead uplifts were carried out under the condition of the double pipe string at different cement return heights and multilayer pipe string coupling cementing and noncementing based on a self-developed HP−HT wellhead uplift simulation device. The results show that the elongation of the double pipe string under the condition of a cement return height of 100% is reduced significantly compared with that under the condition of a cement return height of 50%. Also, the maximum elongation of the multilayer pipe string under the condition of coupling and cementing is significantly reduced compared with that under the condition of noncementing. These show that cement sealing has a binding effect on wellhead uplifts. The error between the calculated and the experimental results is less than 10%; thus, the model can be used to predict the wellhead uplift height under different working conditions and provide technical guidance for designing scientific measures to prevent wellhead uplifts.

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Well-Integrity Issues Offshore Norway

Cited by 30 publications

References 0 publications

The Environmental Costs and Benefits of Fracking

The Environmental Costs and Benefits of Fracking

Numerical investigation of methane and formation fluid leakage along the casing of a decommissioned shale gas well

Influence of Cement Return Height on the Wellhead Uplift in Deep-Water High-Pressure–High-Temperature Wells

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