Coupled Flow and Geomechanics Model for CO 2 Storage in Tight Gas Reservoir
01 Jan 2019-pp 955-967
TL;DR: In this article, a fully coupled fully implicit flow and geomechanics simulator is introduced to describe the physics associated with the injection of CO2 into tight shales, and assess and mitigate the risks associated with reservoir overpressure.
Abstract: The process of injection and withdrawal from tight gas reservoirs is a multiphysics and multicomponent problem. The aim of the present work is to capture the physics associated with the injection of CO2 into tight shales, and assess and mitigate the risks associated with reservoir overpressure. The overpressure caused by CO2 injection usually triggers the onset of formation–deformation, which inadvertently affects the state of the stress in the target geological formations and its surroundings, the monitoring of which is critical to understand the risks in conjunction with CO2 storage. In the present work, a novel fully coupled fully implicit flow and geomechanics simulator is introduced to describe the physics in conjunction with an extended injection phase of CO2. The developed model solves for pressure saturation and porosity and permeability changes considering a multicomponent system while principally focusing on the adsorption and diffusion of CO2 and stress-dependent reservoir deformation employing cell-centred finite volume method. It is envisaged that the injection of CO2, while with the primary purpose of storage, will parallelly enhance the recovery from shale gas due to lateral sweep effects. Based on these mechanisms, for the case study of a tight gas field, the applicability of the simulation model is tested for formations with varied rock and fluid moduli in a 20-year simulation period.
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TL;DR: An overview of pore-scale modeling and micro-CT scan imaging technique for CO2 sequestration including a background of basic concepts related to storage, CO2 enhanced oil recovery, simulators used, and storage estimation is provided in this paper.
Abstract: Global warming is increasing at a perpetual rate due to the emission of greenhouse gases in recent years. This spectacle has been mainly caused by the increase of carbon dioxide (CO2) in the environment. It is in need to find a path to reduce the greenhouse gases along with the additional benefit of energy demand in a sustainable way. A favorable long-term way out to mitigate global warming is to inject CO2 into geological formations of oil fields to achieve a goal of a combination of CO2 sequestration and enhanced oil recovery by CO2 flooding. Understanding the mechanism of CO2 sequestration under impermeable rock formation requires the knowledge of the pore-scale modeling concept. This review article provides an overview of pore-scale modeling and micro-CT scan imaging technique for CO2 sequestration including a background of basic concepts related to storage, CO2 enhanced oil recovery, simulators used, and storage estimation. Trapping mechanisms, geological description of the formation for CO2 sequestration, and reactions that have taken place during the trapping in underground formation are also discussed elaborately. Macro-scale and pore-scale modeling are depicted based on the current literature available. This review also presents petrophysical data that comes from the pore network modeling of CO2-brine pore structure for the formation of carbon-containing sandstone reservoirs. A discussion on the challenges of CO2 sequestration and modeling in pore-scale is also furnished to point out the problems and solutions in near future. Finally, the prospect of CO2 sequestration and pore-scale modeling are described for its uncountable value in greenhouse gas reduction from the environment.
28 citations
TL;DR: In this paper , the authors present the results of analysing geological structure of the Famennian deposits (Devonian) in the Perm Region, where numerical finite element models of near-wellbore zones were created considering slotted and cumulative perforation.
Abstract: The article presents the results of analysing geological structure of the Famennian deposits (Devonian) in the Perm Region. Numerical modelling of the distribution of inhomogeneous stress field near the well was performed for the two considered types of perforation. With regard for the geometry of the forming perforation channels, numerical finite element models of near-wellbore zones were created considering slotted and cumulative perforation. It is ascertained that in the course of slotted perforation, conditions are created for a significant restoration of effective stresses and, as a result, restoration of reservoir rock permeability. Stress recovery area lies near the well within a radius equal to the length of the slots, and depends on the drawdown, with its increase, the area decreases. From the assessment of failure areas, it was found that in case of slotted perforation, the reservoir in near-wellbore zone remains stable, and failure zones can appear only at drawdowns of 10 MPa and more. The opposite situation was recorded for cumulative perforation; failure zones near the holes appear even at a drawdown of 2 MPa. In general, the analysis of results of numerical simulation of the stress state for two simulated types of perforation suggests that slotted perforation is more efficient than cumulative perforation. At the same time, the final conclusion could be drawn after determining the patterns of changes in permeability of the considered rocks under the influence of changing effective stresses and performing calculations of well flow rates after making the considered types of perforation channels.
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References
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TL;DR: In this article, the authors present a long-term energy scenario study for Europe, in which they assess the significance for climate policy making of leakage of CO2 artificially stored in underground geological formations.
Abstract: Geological CO2 capture and storage (CCS) is among the main near-term contenders for addressing the problem of global climate change. Even in a baseline scenario, with no comprehensive international climate policy, a moderate level of CCS technology is expected to be deployed, given the economic benefits associated with enhanced oil and gas recovery. With stringent climate change control, CCS technologies will probably be installed on an industrial scale. Geologically stored CO2, however, may leak back to the atmosphere, which could render CCS ineffective as climate change reduction option. This article presents a long-term energy scenario study for Europe, in which we assess the significance for climate policy making of leakage of CO2 artificially stored in underground geological formations. A detailed sensitivity analysis is performed for the CO2 leakage rate with the bottom-up energy systems model MARKAL, enriched for this purpose with a large set of CO2 capture technologies (in the power sector, industry, and for the production of hydrogen) and storage options (among which enhanced oil and gas recovery, enhanced coal bed methane recovery, depleted fossil fuel fields, and aquifers). Through a series of model runs, we confirm that a leakage rate of 0.1%/year seems acceptable for CCS to constitute a meaningful climate change mitigation option, whereas one of 1%/year is not. CCS is essentially no option to achieve CO2 emission reductions when the leakage rate is as high as 1%/year, so more reductions need to be achieved through the use of renewables or nuclear power, or in sectors like industry and transport. We calculate that under strict climate control policy, the cumulative captured and geologically stored CO2 by 2100 in the electricity sector, when the leakage rate is 0.1%/year, amounts to about 45,000 MtCO2. Only a little over 10,000 MtCO2 cumulative power-generation-related emissions are captured and stored underground by the end of the century when the leakage rate is 1%/year. Overall marginal CO2 abatement costs increase from a few €/tCO2 today to well over 150 €/tCO2 in 2100, under an atmospheric CO2 concentration constraint of 550 ppmv. Carbon costs in 2100 turn out to be about 40 €/tCO2 higher when the annual leakage rate is 1%/year in comparison to when there is no CO2 leakage. Irrespective of whether CCS deployment is affected by gradual CO2 seepage, the annual welfare loss in Europe induced by the implementation of policies preventing “dangerous anthropogenic interference with the climate system” (under our assumption, implying a climate stabilisation target of 550 ppmv CO2 concentration) remains below 0.5% of GDP during the entire century.
87 citations
01 Jan 2009
76 citations
TL;DR: Based on data from the gas field at Fuling, the first large-scale shale gas field in China, this paper concluded that the water intensity for shale gas development in China (water demand per unit lateral length) is likely to exceed that in the US by about 50%.
Abstract: Development of shale gas resources is expected to play an important role in China's projected transition to a low-carbon energy future. The question arises whether the availability of water could limit this development. The paper considers a range of scenarios to define the demand for water needed to accommodate China's projected shale gas production through 2020. Based on data from the gas field at Fuling, the first large-scale shale gas field in China, it is concluded that the water intensity for shale gas development in China (water demand per unit lateral length) is likely to exceed that in the US by about 50%. Fuling field would require a total of 39.9–132.9 Mm3 of water to achieve full development of its shale gas, with well spacing assumed to vary between 300 and 1000 m. To achieve the 2020 production goal set by Sinopec, the key Chinese developer, water consumption is projected to peak at 7.22 Mm3 in 2018. Maximum water consumption would account for 1% and 3%, respectively, of the available water resource and annual water use in the Fuling district. To achieve China's nationwide shale gas production goal set for 2020, water consumption is projected to peak at 15.03 Mm3 in 2019 in a high-use scenario. It is concluded that supplies of water are adequate to meet demand in Fuling and most projected shale plays in China, with the exception of localized regions in the Tarim and Jungger Basins.
71 citations
TL;DR: In this paper, an integrated geomechanical analysis has been performed for the construction of a one-dimensional Mechanical Earth Model (MEM) for a vertical well drilled in a naturally fractured tight carbonate gas reservoir of Oxfordian age in the Persian Gulf.
63 citations
TL;DR: In this article, a joint model is introduced to describe joint reactivation during injection of CO2, assuming equally spaced anisotropic joint sets with non-linear normal stiffness and linear shear stiffness.
52 citations