CO2 sequestration-EOR in Yanchang oilfield, China: Estimation of CO2 storage capacity using a two-stage well test

With recent concerns on CO2 emissions from coal fired electricity generation plants; there has been major emphasis on the development of safe and economical Carbon Dioxide Capture and Sequestration (CCS) technology worldwide. Saline reservoirs are attractive geological sites for CO2 sequestration because of their huge capacity for sequestration. Over the last decade, numerical simulation codes have been developed in U.S, Europe and Japan to determine a priori the CO2 storage capacity of a saline aquifer and provide risk assessment with reasonable confidence before the actual deployment of CO2 sequestration can proceed with enormous investment. In U.S, TOUGH2 numerical simulator has been widely used for this purpose. However at present it does not have the capability to determine optimal parameters such as injection rate, injection pressure, injection depth for vertical and horizontal wells etc. for optimization of the CO2 storage capacity and for minimizing the leakage potential by confining the plume migration. This paper describes the development of a “Genetic Algorithm (GA)” based optimizer for TOUGH2 that can be used by the industry with good confidence to optimize the CO2 storage capacity in a saline aquifer of interest. This new code including the TOUGH2 and the GA optimizer is designated as “GATOUGH2”. It has been validated by conducting simulations of three widely used benchmark problems by the CCS researchers worldwide: (a) Study of CO2 plume evolution and leakage through an abandoned well, (b) Study of enhanced CH4 recovery in combination with CO2 storage in depleted gas reservoirs, and (c) Study of CO2 injection into a heterogeneous geological formation. Our results of these simulations are in excellent agreement with those of other researchers obtained with different codes. The validated code has been employed to optimize the proposed water-alternating-gas (WAG) injection scheme for (a) a vertical CO2 injection well and (b) a horizontal CO2 injection well, for optimizing the CO2 sequestration capacity of an aquifer. These optimized calculations are compared with the brute force nearly optimized results obtained by performing a large number of calculations. These comparisons demonstrate the significant efficiency and accuracy of GATOUGH2 as an optimizer for TOUGH2. This capability holds a great promise in studying a host of other problems in CO2 sequestration such as how to optimally accelerate the capillary trapping, accelerate the dissolution of CO2 in water or brine, and immobilize the CO2 plume.

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Two-Stage, Integrated, Geothermal-CO2 Storage Reservoirs: An Approach for Sustainable Energy Production, CO2-Sequestration Security, and Reduced Environmental Risk

10.2172/1035606 ◽

2012 ◽

Cited By ~ 3

Author(s):

T Buscheck ◽

M Chen ◽

Y Sun ◽

Y Hao ◽

T Elliot

Keyword(s):

Environmental Risk ◽

Co2 Sequestration ◽

Energy Production ◽

Sustainable Energy ◽

Co2 Storage ◽

Two Stage ◽

Storage Reservoirs

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ASCAPE: A Flexible and Efficient Analytical Tool to Evaluate Aquifer Storage Capacity for CO2 Sequestration

10.2118/208222-ms ◽

2021 ◽

Author(s):

Fabrizio Freni ◽

Vincenzo Napolitano ◽

Silvia Mancini ◽

Roberto Buscaglia

Keyword(s):

Co2 Sequestration ◽

Storage Capacity ◽

Water Pressure ◽

Co2 Storage ◽

Economic Feasibility ◽

Preliminary Evaluation ◽

Water Production ◽

Co2 Solubility ◽

Aquifer Storage ◽

Pressure Increment

Abstract In recent years, carbon neutrality has emerged as an important social and political focus globally, where carbon sequestration plays a key role. The present work is aimed at introducing ASCAPE (Aquifer Storage CAPacity Evaluation tool), a fast and flexible tool useful in case of CO2 aquifer sequestration to preliminarily evaluate the required storage capacity as a function of the maximum allowable pressure increment. ASCAPE is based on the volumetric method included in SPE "Guidelines for Applications of the CO2 Storage Resources Management System" (SPE, 2020) for aquifer sequestration. The analytical formula was integrated to include additional physical phenomena as CO2 solubility in water, pressure control through water production, effect of gas pools connected to aquifer. The tool, implemented in Excel/VBA environment, allows to easily obtain a theoretical Pressure increment vs. Aquifer Volume curve useful to estimate the required aquifer volume to store a given quantity of CO2. ASCAPE results were validated comparing to a simplified 3D model simulated by a compositional commercial dynamic simulator. The validation showed a very good alignment with the 3D dynamic simulation results under several conditions. Many tests were performed with and without the CO2 solubility model, demonstrating that this phenomenon acts as pressure increment reducer. The original volumetric model can be therefore considered slightly conservative, since it neglects this physical contribution, which allowed to improve the reliability of the proposed analytical model. The proposed methodology is a general-purpose application being not related to a specified candidate and, therefore, it can be tailored on the specific scenario to be evaluated. ASCAPE was developed for preliminary screening of CO2 sequestration concepts in greenfield development areas, where the absence of brown or exhausted fields makes the storage in aquifer the only viable solution. Different aquifers were compared under certain assumptions of carbon to be stored with and without water production, allowing a preliminary evaluation that will be used to rank the concepts in terms of technical/economic feasibility.

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