| 1. |
- Joodaki, Saba, et al.
(författare)
-
Model analysis of CO2 residual trapping from single-well push pull test - Heletz, Residual Trapping Experiment II
- 2020
-
Ingår i: International Journal of Greenhouse Gas Control. - : ELSEVIER SCI LTD. - 1750-5836 .- 1878-0148. ; 101
-
Tidskriftsartikel (refereegranskat)abstract
- Residual or capillary trapping is one of the key trapping mechanisms for CO2 geological storage. At the Heletz, Israel, pilot injection site, two dedicated field experiments have been carried out to characterize it in-situ. This paper presents the model analyses of the second of these tests, the Residual Trapping Experiment II (RTE II). In the experiment hydraulic, tracer and thermal tests before and after the generation of the residually trapped zone are used to quantify residual saturation. The creation of the residually trapped zone is based on injection of CO2-saturated-water following injection of free-phase supercritical CO2. For the modeling, both a radial-symmetric model with homogeneous layer properties and 3D model with stochastically heterogeneous properties were used. Extensive parameter sensitivity studies were carried out and various well-geometry related fluid injection/withdrawal scenarios were considered. In terms of the best estimate for the maximum residual saturation, this experiment, like the previous RTE I experiment, gave the best agreement with a residual gas saturation of 0.1, this value being somewhat lower than the core-measured value of 0.2. Overall, the pressure response provided a very robust signal enabling to distinguish different values of residual saturation as well as the extent of sections where gas blocking for water flow could have occurred. Analysis of the tracer data indicated the presence of phenomena such as gas-blocking water flow, the importance of multi-layer and channelized flow and transport, and the importance of taking into account the processes in the actual injection/production well also.
|
|
| 2. |
- Khormali, Azizollah, et al.
(författare)
-
Development of a new chemical solvent package for increasing the asphaltene removal performance under static and dynamic conditions
- 2021
-
Ingår i: Journal of Petroleum Science and Engineering. - : Elsevier. - 0920-4105 .- 1873-4715. ; 206
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, a new solvent package (named TPMDS) for asphaltene removal under static and dynamic conditions was developed through a set of experiments. TPMDS consists of toluene, pyridine, methanol, surfactant dodecylbenzenesulfonic and sodium hydroxide. The optimum concentrations of TPMDS components were determined based on the efficiency evaluation of the chemical reagents to eliminate the asphaltene precipitation under static conditions. The highest effectiveness of the developed solvent package under static conditions was found to be 98%, which was observed at a soaking time of 6 h and a mass concentration of 1%. TPMDS had high performance (more than 97.5%) for asphaltene removal in four different oil samples containing various asphaltene concentrations. The results of the turbidity and dissolution rate experiments of asphaltene in the presence of TPMDS and toluene showed that the performance of TPMDS for asphaltene removal is significantly better than toluene. In addition, core flood tests were carried out with the use of TPMDS and toluene. Pressure drop due to asphaltene precipitation in the carbonate core samples was reduced eight times using the developed solvent package. The damaged permeability due to asphaltene deposition was 51% of the initial rock permeability before injection of any solvent. The results of core flood tests showed that the rock permeability has reached about 94% and 71% of the initial permeability after injection of TPMDS and toluene, respectively. Despite the increase in the amount of asphaltene precipitation in the core samples by increasing injection rate, the efficiency of the developed solvent was not decreased by changing the injection rate since the performance of the TPMDS was improved by the appearance of a synergistic effect for asphaltene dissolution. Furthermore, oil viscosity reduction with the use of TPMDS was more significant than with the use of toluene. The corrosion rate of the metal samples in the presence of the developed solvent package solution was less than 0.08 mm/year in a temperature range from 25 degrees C to 100 degrees C, which is less than an acceptable threshold corrosion rate of 0.1 mm/year. Moreover, the results of field analysis showed that the oil production rate could be enhanced by 3.3 times after treatment by TPMDS. Asphaltene removal effectiveness in the production wells using the industrial reagent and TPMDS has reached 84 and 96%, respectively. The rock permeability after treatment by TPMDS was increased by about 290%. TPMDS can be used for asphaltene removal in the near-wellbore region, production equipment, and tubing.
|
|
| 3. |
- Moghadasi, Ramin, et al.
(författare)
-
A Stochastic Model for Interpreting the Partitioning Tracer Recovery from Residual Trapping Experiment at Heletz, Israel, Pilot Injection Site
- 2019
-
Konferensbidrag (refereegranskat)abstract
- Residual trapping is one of the key trapping mechanisms for geological storage of CO2. While relatively abundant experimental data exists on laboratory cores, only very few experiments have attempted to address this parameter in the field. As part of the experimental program at Heletz, Israel, pilot CO2 injection site (Niemi et al. 2012, 2016), two small-scale push-pull CO2 injection experiments were carried out to determine residual trapping in-situ (Niemi et al. 2012). In the second one of these experiments, carried out in 2017, the main method for characterizing the residual trapping was injection of partitioning tracer Krypton before and after creating the residually trapped zone. This paper presents one of the model interpretations of the tracer experiment, by assuming a stochastically heterogeneous interpretation of the properties of the storage reservoir. Based on field data on layer properties, heterogeneous models are generated using geostatistical library GSLIB (Finsterle and Kowalsky 2007) and multiple realization Monte Carlo simulations of the experiment test sequence are carried out using the simulator iTOUGH with the equation of state modules EOS7C/ECO2N (Pruess 2005: Oldenburg et al. 2004). Effect of heterogeneity characteristics on simulated tracer recovery is analyzed and compared to that from the field data. The results provide us a better understanding on how heterogeneity effects can influence partitioning tracer behavior and its partitioning into trapped CO2.
|
|
| 4. |
- Moghadasi, Ramin, et al.
(författare)
-
Determining Gas Re-Mobilization and Critical Saturation : From Field Scale CO2 Injection Experiments to Pore-Scale Modelling
- 2022
-
Ingår i: Proceedings of the 16th Greenhouse Gas Control Technologies Conference (GHGT-16) 23-24 Oct 2022. - : Greenhouse Gas Control Technologies (GHGT).
-
Konferensbidrag (refereegranskat)abstract
- Residual trapping is a key mechanism in geological CO2 storage, which is quantitively characterized by residual gas saturation (Sgr). Remobilization of residually trapped CO2 can occur during pressure depletion, which can take place due to dissipation of near wellbore pressure build-up or any type of leakage. The occurrence of remobilization is characterized quantitively by critical gas saturation (Sgc). In this study, we present the first ever field-scale observations of trapped gas remobilization in the context of CO2 storage. We then present the preliminary results from pore-network modelling (PNM) study using a 3D network constructed from a series of X-ray computed tomography (CT) on Heletz sandstone. Our findings provide a multi-scale insight into the remobilization process in the context of CO2 storage and outline future work in terms of modelling the process to achieve a better assessment of stability of CO2 residual trapping in long-terms.
|
|
| 5. |
- Moghadasi, Ramin, et al.
(författare)
-
Determining residual gas remobilization and critical saturation in geological CO2 storage by pore-scale modelling
- 2022
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Remobilization of residually trapped CO2 as a result of pressure depletion occurs inherently at the pore-scale but affects the long-term stability of the residual trapping of CO2 at larger scales. In this study, pore-network modelling (PNM) is used to investigate this phenomenon under pressure depletion conditions. 3D networks of Bentheimer and Heletz sandstone as well as statistically generated generic 2D and 3D networks are used. The gas remobilization does occur at a higher gas saturation than residual saturation, so-called critical saturation. The difference is denoted as mobilization saturation, which varies according to the network properties (e.g., dimensionality) and the processes/mechanisms involved. Slightly smaller values are obtained for 3D networks due to the higher order of geometric connectivity between the pores and the effects of gravity. Regardless of the network types and properties, Ostwald ripening tends to slightly increase the mobilization saturation, thereby enhancing the security of residual trapping. Moreover, a significant hysteresis and reduction in gas relative permeability is observed during the depletion process, implying slow reconnection of the trapped gas clusters. These observations are safety enhancing features, due to which the remobilization of the residual trapped CO2 is delayed. The results, which are consistent with our previous analysis of field-scale Heletz experiments, have important implications for underground gas and CO2 storage. In the context of geological CO2 storage, they provide important insights into the fate of residual trapping in both the short and long term.
|
|
| 6. |
- Moghadasi, Ramin, et al.
(författare)
-
Pore-scale characterization of residual gas remobilization in CO2 geological storage
- 2023
-
Ingår i: Advances in Water Resources. - : Elsevier. - 0309-1708 .- 1872-9657. ; 179
-
Tidskriftsartikel (refereegranskat)abstract
- A decrease in reservoir pressure can lead to remobilization of residually trapped CO2. In this study, the pore-scale processes related to trapped CO2 remobilization under pressure depletion were investigated with the use of highresolution 3D X-ray microtomography. The distribution of CO2 in the pore space of Bentheimer sandstone was measured after waterflooding at a fluid pressure of 10 MPa, and then at pressures of 8, 6 and 5 MPa. At each stage CO2 was produced, implying that swelling of the gas phase and exsolution allowed the gas to reconnect and flow. After production, the gas reached a new position of equilibrium where it may be trapped again. At the end of the experiment, we imaged the sample again after 30 hours. Firstly, the results showed that an increase in saturation beyond the residual value was required to remobilize the gas, which is consistent with earlier field-scale results. Additionally, Ostwald ripening and continuing exsolution lead to a significant change in fluid saturation: transport of dissolved gas in the aqueous phase to equilibriate capillary pressure led to reconnection of the gas and its flow upwards under gravity. The implications for CO2 storage are discussed: an increase in saturation beyond the residual value is required to mobilize the gas, but Ostwald ripening can allow local reconnection of hitherto trapped gas, thus enhancing migration and may reduce the amount of CO2 that can be capillary trapped in storage operations.
|
|
| 7. |
- Moghadasi, Ramin, et al.
(författare)
-
Pore-scale characterization of residual phase remobilization in geological CO2 storage using X-ray microtomography and pore-network modelling
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this study, the pore-scale characteristics of trapped CO2 remobilization under pressure depletion conditions were studied with the use of 3D X-ray microtomography and pore-network modelling. Three-dimensional X-ray microtomographic images of a sandstone sample with a voxel size of 3.83 mm were acquired from which a pore network was extracted. Experimental results show that trapped CO2 remobilization during pressure depletion is an intermittent process in nature, due to which the CO2 relative permeability is significantly reduced. This serves as a safety enhancing feature as it delays CO2 remobilization and migration. Ostwald ripening plays a significant role in the CO2 phase redistribution, which could potentially lead to remobilization even in the absence of pressure depletion. According to the pore network simulation results, weakly wetting conditions enhances the reconnection of the trapped CO2 ganglia, which in turn promotes the remobilization of the trapped phase. The simulation and experimental results agree in terms of the saturation increment needed to remobilize the CO2 – approximately 0.06 – and the pressure at which the CO2 connects – around 7 MPa. The findings of the current study provide valuable insights into the pore-scale aspects of trapped phase remobilization, a phenomenon that affects the fate of CO2 residual trapping in both the short and long term.
|
|
| 8. |
- Moghadasi, Ramin, et al.
(författare)
-
Pore‐Scale Determination of Residual Gas Remobilization and Critical Saturation in Geological CO2 Storage : A Pore‐Network Modeling Approach
- 2023
-
Ingår i: Water resources research. - : American Geophysical Union (AGU). - 0043-1397 .- 1944-7973. ; 59:6
-
Tidskriftsartikel (refereegranskat)abstract
- Remobilization of residually trapped CO2 can occur under pressure depletion, caused by any sort of leakage, brine extraction for pressure maintenance purposes, or simply by near wellbore pressure dissipation once CO2 injection has ceased. This phenomenon affects the long-term stability of CO2 residual trapping and should therefore be considered for an accurate assessment of CO2 storage security. In this study, pore-network modeling is performed to understand the relevant physics of remobilization. Gas remobilization occurs at a higher gas saturation than the residual saturation, the so-called critical saturation; the difference is called the mobilization saturation, a parameter that is a function of the network properties and the mechanisms involved. Regardless of the network type and properties, Ostwald ripening tends to slightly increase the mobilization saturation, thereby enhancing the security of residual trapping. Moreover, significant hysteresis and reduction in gas relative permeability is observed, implying slow reconnection of the trapped gas clusters. These observations are safety enhancing features, due to which the remobilization of residual CO2 is delayed. The results, consistent with our previous analysis of the field-scale Heletz experiments, have important implications for underground gas and CO2 storage. In the context of CO2 storage, they provide important insights into the fate of residual trapping in both the short and long term.
|
|
| 9. |
- Moghadasi, Ramin
(författare)
-
Residual and critical saturation in geological storage of CO2 : results from field studies, pore-network modelling and laboratory experiments
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Geological storage of CO2 in deep saline aquifers is a promising technology in the combat to reduce the atmospheric emissions of CO2. A critical component in this solution is the estimation of aquifer’s in situ capability to store CO2. For this, an in-depth understanding of the underlying processes is required over a wide range of scales, from the pore level where processes occur, to field scale that needs to be controlled and monitored. This Thesis is focused on residual trapping – quantitively characterized by the parameter residual gas saturation (Sgr) – which is one of the key trapping mechanisms. The overall objective is to better understand the relevant in situ phenomena that affect the stability of CO2 residual trapping over a range of scales. Important part of this are the processes controlling the residual gas remobilization that is characterized quantitively by so-called critical gas saturation (Sgc). To this end, first, numerical modelling was implemented at the field-scale to investigate the role of permeability heterogeneity and critical gas saturation in the interpretation of the collected partitioning tracer data from a pilot-scale CO2 injection experiment carried out at Heletz, Israel, 2017. With regards to this experiment, the delayed second arrival peak of the partitioning tracer could not be captured by physical processes included in presently available models, including a stochastic model of within-layer permeability heterogeneity. The results could, however, be explained by accounting for the critical gas saturation that indicates the occurrence of gas-phase remobilization driven by pressure depletion. This is the first ever field observation and demonstration of critical saturation in geological CO2 storage. The relevant fundamental pore-scale characteristics of remobilization are then investigated by means of pore-scale imaging and modeling. The results illustrate that under pressure depletion conditions (which could be caused by e.g., a leaky wellbore or a facture) remobilization of residually trapped CO2 takes place at a higher saturation than residual saturation with the difference depending on various rock and fluid properties. Furthermore, the results provide valuable insights into the pore-scale dynamics of trapped gas remobilization. A very good consistency was found between the pore-scale results and field-scale observations, which provides unique insights into the fate of CO2 residual trapping and remobilization across a wide range of scales.
|
|
| 10. |
- Moghadasi, Ramin, et al.
(författare)
-
Role of critical gas saturation in the interpretation of a field scale CO2 injection experiment
- 2022
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier. - 1750-5836 .- 1878-0148. ; 115
-
Tidskriftsartikel (refereegranskat)abstract
- Residual trapping of CO2, typically quantified by residual gas saturation (Sgr), is one of the main trapping mechanisms in geological CO2 storage (GCS). An important additional characteristic parameter is critical gas saturation (Sgc). Sgc determines at what saturation the trapped gas remobilizes again if gas saturation increases due to exsolution from the aqueous phase, rather than from further gas injection. In the present study, a pilot-scale CO2 injection experiment carried out at Heletz, Israel, in 2017, is interpreted by taking critical saturation into account. With regards to this experiment, the delayed second arrival peak of the partitioning tracer could not be captured by means of physical models. In this work, the hysteretic relative permeability functions were modified to account for Sgc. The results showed that accounting for the effect of Sgc during the secondary drainage indeed captured the observed delayed peak. The difference between the values of Sgr and Sgc, influenced both the time and peak height of the tracer arrival. To our knowledge this is first time that critical gas saturation has been considered in field scale analyses related to GCS. Accounting for Sgc is relevant where gas saturation during secondary drainage increases due to gas phase expansion or exsolution from the aqueous phase. This will happen in situations where pressure depletion occurs, e.g. due to gas leakage from fracture zones or wells or possibly because of pressure management activities. The findings also have implications for other applications such as underground gas storage as well as for geothermal reservoir management.
|
|
