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Abstract Enhanced oil recovery (EOR) using CO2 is an important recovery process that can increase recoverable hydrocarbons and sequester CO2 simultaneously. For light oils, CO2 injection is particularly interesting and is considered a win-win strategy that sequesters CO2 and provides additional oil reserves at the same time. Saudi Aramco has designed and implemented the first CO2-EOR demonstration project in one of the fields. It is worth mentioning that while Saudi Aramco does not require EOR oil for decades to come, this project is being pursued primarily to demonstrate the feasibility of sequestering CO2 through EOR in the Kingdom and using it as grounds to test new monitoring and surveillance (M&S) techniques. The project consists of two components: the actual EOR project in a small part of a field, and the CO2 capture plant. An overall plan covering laboratory and research studies, reservoir modeling and simulation, monitoring and surveillance, construction of a CO2 capture facility, project implementation and evaluation will be presented for this first demonstration project. The project uses 40 million standard cubic feet per day (MMscf/d) of CO2 that is being captured and processed from an existing facility and piped about 85 km to the field location. An innovative progressive infill line drive has been implemented to take advantage of the east-west fluxes in the field. This includes a row of four injectors and four producers, and another set of observations wells for monitoring and surveillance. The CO2 is being injected in a water-alternating-gas (WAG) mode. An elaborate monitoring and surveillance program has been established and currently being implemented to evaluate the performance of the project. It includes the deployment of several new technologies including seismic, inter-well tracers, gravity, geochemical sampling and analyses that will be discussed in the paper. The main objectives of the demonstration project are estimation of sequestered CO2, determination of incremental oil recovery, addressing the risks and uncertainties involved, including migration of CO2 within the reservoir and operational concerns. It is estimated that up to ~40% of the injected CO2 will be sequestered permanently in the reservoir.
Balasubramanian, Senthilmurugan (Saudi Aramco) | Sanni, Modiu (Saudi Aramco) | Kokal, Sunil (Saudi Aramco) | Oduro, Harry (Saudi Aramco) | Yu, Haichao (Saudi Aramco) | Al-Hajji, Adnan (Saudi Aramco) | Adam, Frederick (Saudi Aramco)
Abstract Saudi Aramco is implementing its first carbon-dioxide enhanced oil recovery (CO2-EOR) carbon capture, utilization and storage (CCUS) demonstration project in a small depleted part of a carbonate reservoir, as part of its environmental stewardship and its efforts to mitigate CO2 emissions. It is worth mentioning that Saudi Aramco does not require EOR oil for many decades to come. This project is being implemented primarily to demonstrate the feasibility of sequestering CO2 through EOR in the Kingdom and using it as grounds to test new monitoring and surveillance (M&S) technologies. The injected CO2 is expected to react with formation fluid (oil and water) and rock minerals for geological storage to occur. Reservoir simulation studies suggest about 40-50% of the injected CO2 will be sequestered permanently in the reservoir. To understand the geological trapping process and also to identify and quantify any inadvertent "out-of-zone" CO2 leakage, a comprehensive geochemical monitoring (geochem) program has been developed and is being deployed. The objectives of the geochem program are to monitor the project before, during and after CO2 injection to assess the efficacy of the sequestration process. In addition, the geochem data will provide the pertinent information for calibrating the CO2 reactive transport model to be used to quantify and predict the amount of CO2 that will be sequestered over a long period. The geochem plan includes monitoring the changes in basic ionic compositions of reservoir and aquifer water, pH, dissolved organic carbons (DOCs), volatile organic carbons (VOCs), BTEX, etc., and changes in isotopes of carbon, oxygen, hydrogen. Furthermore, the plan also includes monitoring the changes in soil gas (CO2, CH4, O2, Ar, Rn, and He) concentration. Baseline and time-lapse data are being collected. These provide the basic input to our reactive transport model. The results from the analyses of the reservoir fluid indicate very little value may be derived from monitoring time-lapse isotopic changes. Isotope clumping is considered as a better approach to understand and quantify the amount CO2 being sequestered. This paper reviews the design and implementation of the geochem plan for the project, operational issues, the results obtained to date and the use of "clumped-isotope" geochemistry. Plans for further implementation of the geochem program and the lessons learned will be shared. The geochem plan is deemed robust and will help with understanding, tracking, monitoring and predicting the geo-sequestration process.
Abstract CO2 Capture and geological Storage (CCS) is a technology that is available today and that can cost-effectively solve up to a quarter of the global Greenhouse gas (GHG) problem. CCS can be applied to any fixed, point-source of CO2, and will likely be most cost-effective when applied to large sources close to large sinks. While CCS has application in the oil and gas sector (both upstream and downstream), the largest sources of CO2 exist in the power sector. Oil and gas sources are typically less than one million metric tonnes per annum (mmtpa) CO2, whereas power sector sources are typically more than 5mmtpa CO2. Hence a large-scale sequestration project should store in the order of 1mmtpa CO2. Around 30mmtpa CO2 is being injected into EOR projects, mostly in the USA and Canada. Those EOR projects are being managed to recover and re-inject the CO2 (that they have to buy), rather than sequester it - little or no monitoring is carried out for the purpose of assuring CO2 geological storage. As of today, there are only 4 large-scale projects on the planet which sequester anthropogenic CO2 on the 1mmtpa-scale: Sleipner (Norway), In Salah (Algeria), Weyburn-Midale (Canada) and Snøhvit (Norway). Of these the two most significant (in terms of cumulative volume injected and experience of CO2 storage) are Sleipner (which has been in operation for 13 years) and In Salah (5 years). Weyburn-Midale is a CO2 EOR project involving CO2 cycling and monitoring. Although a portion of the cycled CO2 will be permanently stored, the primary objective of the project is to recover EOR oil. Snøhvit is relatively new (starting injection in 2008) and has not yet stored a significant volume of CO2. We focus therefore on the experience from the two large and mature projects Sleipner and In Salah. These two projects both capture CO2 produced during natural gas processing and store CO2 in deep saline formations. For both projects, the storage was part of the integrated Field Development Plan. They were both permitted under hydrocarbon law, and they illustrate significantly different aspects of storage: technical and commercial. Commercial Frameworks The Sleipner project was mainly stimulated by the introduction in 1991 of the Norwegian offshore CO2 tax (~$50/tonne). The project costs (capex and opex) are essentially covered by avoiding this tax and the project has now passed the break even point in the investment cycle. In contrast, the In Salah project was initiated without tax incentives, but as an initiative by the Operators to avoid excessive additional CO2 emissions to the atmosphere. It is however hoped that the project will qualify for CDM credits under the Kyoto Protocol (but those have not been approved to date).
Abstract To achieve substantial national and global greenhouse gas abatement, carbon capture and sequestration (CCS) must be deployed at large scale in many locations. Individual large projects (5 million tons/y) will inject volumes on the order of 80,000–130,000 bbls/day equivalent continuously for 30 years or more. This requires explicit consideration of and management of growing reservoir pressure unlike CO2-EOR. Accurate reservoir descriptions of fault networks and the in-situ stress tensor are critical to successful management. Small uncertainties in the structural geometry or stress tensor azimuth can potentially produce very different results for fault activation and risk, which in turn affect the potential for induced seismicity in an active injection. Although smaller than the injection pressure wave, the large injection footprint will make monitoring and verification challenging. Key challenges involve reduction of cost and improvement of accuracy using non-seismic methods. Careful integration of monitoring results and understanding of uncertainties are critical to avoid subsurface trespass and far-field migration. Demonstrations of InSAR, microseismic, and electrical survey methods have improved understanding of these technologies and may lead to improved monitoring suites. Seafloor monitoring has received little attention, but will be central to shelf deployments. Direct monitoring of groundwater systems may also be required by regulations, but have received little attention. In order to avoid excessive local build-up of pressure and to maintain a small injection footprint, active management of the reservoir may be needed. Co-production and treatment of reservoir brines could provide a cost-effective means of reducing both operational risk and project costs. More aggressive reservoir management (interception wells and induced flow fields) may be needed to avoid trespass onto adjacent properties. Such measures are standard practice in many oilfield operations, suggesting that the incremental cost and risk posed by active management is likely to be small. Introduction Since first proposed (Marchetti, 1977), carbon capture and sequestration (CCS) through geological storage has gained in prominence as a greenhouse gas abatement strategy. This is reflected in part through the three commercial CCS projects (Weyburn, In Salah, and Snohvit) and the numerous field demonstrations (e.g., Frio, Otway, Nagaoka, CO2SINK) which have entered the field in the last 10 years (Michael et al., 2009). It is also reflected in conclusions by the IPCC, EIA, IEA, WEC, MIT, and others that CCS is a key component of any strategy for steep CO2 emissions reductions (REFS), as well as the creation of institutions like the DOE regional partnerships, the Carbon Sequestration Leadership Forum, and the Global CCS Institute. Finally, the large number of proposed large CCS projects has grown dramatically in the past 3 years, including ZeroGen, Gorgon, GreenGen, Schwartzepumpe, HECA, NowGen, and FutureGen.
Abstract Fossil fuel fired plants are responsible for the one third of the carbon dioxide (CO2) emissions which thought to be a major contributor to the current rise in the Earth's surface temperature. Reducing CO2 atmospheric concentrations by capturing emissions at the source---power plants or chemical units---and then storing them in subsurface reservoirs is thought by many scientists to be a reliable solution until emission-free energy sources are developed and viable. The current options for captured CO2 utilization are; Enhanced Oil Recovery (EOR), Enhanced Coal Bed Methane Recovery (ECBM), Enhanced Gas Recovery (EGR), Food processing applications, Mineral products, Fertilizer manufacture, Algae growth promoter, Enhanced plant growth. The capture and storage of CO2 continues to accelerate as new projects are initiated and existing projects confirm the development scenarios. A crucial element in CO2 storage is reliable monitoring of CO2 migration behavior and storage volumes. An innovative seismic monitoring techniques, has recently been awarded a U.S. Department of Energy (DOE) project that will examine the application of time-lapse (4D) seismic technology and advanced reservoir simulation to optimize CO2 EOR operations. Well design, cementing, completions techniques and long life cycle mechanical integrity assurance are currently subject of many R&D projects. Industry expertise also is being tapped in CO2 projects across Europe and in Australia, including four major EU proposals under the Framework Program Six and the Australian CO2CRC Otway Project. These projects address pertinent issues in CO2 capture and storage such as site selection, storage monitoring and verification techniques, developing local CO2 storage sites from hydrogen- and power-generation plants, and industry training. In our paper framework of CO2 sequestration and vital aspects such as; site selection, reservoir characterization, modeling of storage and long term leakage monitoring techniques will be illustrated. Introduction The prospect of global warming is a matter of genuine public concern. The concentration of carbon dioxide in the atmosphere has been increasing since industrialization in the 19th century, and consensus is forming that mankind is having a visible impact on the world's climate. It is generally acknowledged that the most important environmental impact of fossil fuel burning is an increased global warming from the buildup of greenhouse gases in the atmosphere. This warming occurs when the added greenhouse gases trap more of the earth's outgoing heat radiation. There is a wide consensus from extensive research in the last three decades that rapid climate change is already happening, that global average temperatures are increasing at unprecedented rates. In parallel, CO2 emissions from anthropogenic sources have also been increasing in the same time frame and these are known to produce a greenhouse effect. The greatest contributor to global warming over the past century has been carbon dioxide, mostly from deforestation and fossil fuel burning. Methane is second and arises from coal deposits, leaking natural gas pipelines, landfills, forest fires, wetlands, rice growing, and cattle rising. Nitrous oxide, also known as "laughing gas," is third and arises from agricultural practices, fuel burning and industrial processes (Figure 1). The foremost contributor to increased atmospheric CO2 is fossil fuel combustion for power generation, transport, industry, and domestic use. Energy from fossil fuels has provided a high standard of living in industrialized countries and the demand for energy continues to grow as developing countries seek to raise their standards of living.