Carbonate rock dissolution during CO2 and brine injection – An experimental study applying in-situ imaging by PET and CT

Carbon Capture and Storage (CCS); capture of CO2 from point sources followed by permanent storage in subsurface geological formations; can contribute to mitigating anthropogenic CO2 emissions, and to the ongoing energy transition, by reducing climate impacts from petroleum production. CO2 that is injected into subsurface reservoirs will interact with the reservoir fluids; unavoidably dissolving in already present water (injected or formation). The result is acidic conditions in the reservoir, which can promote the dissolution of rock matrix. Dissolution may especially be an issue in reactive carbonate rocks. Carbonate reservoirs contain approximately 60% of the remaining hydrocarbon resources globally, and significant volumes of CO2 may be stored in saline aquifers within carbonate formations. Understanding geochemical interactions that occur when CO2 is injected into subsurface formations for storage is important: dissolution may, depending on location and pattern, benefit injectivity and/or threaten well integrity, cause geo-mechanical weakening, or create preferential flow paths within the reservoir which decreases the overall sweep efficiency. Dissolved matrix particles may flow within the reservoir and cause clogging of pores and throats, which may increase CO2 storage security by reducing CO2 migration or be detrimental to the rock flow and storage capacity. Investigation of dissolution on the core scale forms the basis for predictions of reactive transport and its effects on larger scales. The main objectives of this thesis were to 1) investigate dissolution of carbonate core samples during co-injection of supercritical CO2 and brine, and 2) utilize emerging in-situ imaging techniques to quantify reactive fluid flow, dissolution patterns, and changes in local rock structure. Co-injection was performed at reservoir conditions (40°C and 90bar), into five Edwards Yellow limestone core samples. The cores were fractured before co-injection, to localize the reactive fluid flow and promote dissolution and the formation of preferential pathways (wormholes) in and around the fracture. Two different fracture networks were utilized: a tight fracture network with a pre-existing longitudinal flow-channel along one side (A) and a closed fracture network with a tight longitudinal fracture (B). Global measurements of pressure and volumetric flow rates, and dynamic measurements of effluent pH were used to describe dynamic dissolution during co-injection of CO2 and brine. Computed Tomography (CT) imaging was used to gain insight into initial rock structure, and the dissolution pattern that had formed during co-injection. Micro-CT (µ-CT) provided high spatial resolutions (tens of µm scale) for detailed investigations of the fracture and matrix structure, while a preclinical CT module was used to characterize fracture and heterogeneities at mm-scale. CT combined with emerging imaging technique Positron Emission Tomography (PET) provided detailed insight into the relation between the evolving dissolution pattern (changes in pore structure) and local reactive flow regime. Co-injection of CO2 and brine into fractured carbonate core samples caused dissolution of the rock material in all five core samples. For fracture network (A) with a pre-existing high-conductivity channel, wormholes formed due to local dissolution within the conductive channel. Global measurements showed increased injectivity with time, but failed to predict the size and location of dissolution visualized by PET and CT. In tight fracture network (B) injectivity decreased during co-injection, estimated from global measurements. Visual observations, however, showed significant dissolution at the injection side of the core samples. In-situ visualization revealed that reactive transport and dissolution also had occurred outside of the fracture area, indicating that the tight fracture network had been partially or fully blocked by particles, and fluids diverted into the pore network. In-situ imaging was necessary to determine changes in structure and flow during CO2 injection, and revealed significant dissolution heterogeneities that could not be well captured with global measurements.Masteroppgave i petroleumsteknologiPTEK399MAMN-PET

Tollarsjuka hos hund

"Tollarsjuka" is a disease with a suspected immunopathological background seen in Nova Scotia duck tolling retrievers. Pyrexia, lameness, stiffness and joint- or musclepain are typical clinical signs. The purpose of this study is to describe case histories from dogs with a possible evidence of "tollarsjuka". 18 private dogs were included in this report. Generalised stiffness, lameness and fatigue were the most frequent manifestations of the disease. Radiographical examination of painful joints and joint fluid analysis from two dogs indicated an immune-mediated, non-erosive arthritis in evaluated dogs. Hematological and serological examination of the blood revealed no changes of importance for the development of "tollarsjuka". Serum protein electrophoresis was performed in 12 dogs and documented a mild decrease in the concentration of albumin. This may be due to an early glomerulonephritis often seen in dogs manifesting a systemic, autoimmune disease. Antibodies specific for Borrelia burgdorferi and Ehrlichia equi (Anaplasma phagocytophilum) were detected in the blood from three evaluated dogs. It is uncertain whether borrelia/ehrlichia is actually causing an immunemediated arthritis in these cases. Corticosteroid and/or NSAID-treatment performed in 15 dogs resulted in a clinical improvement, but not always in complete recovery. This study reveals no certain correlation between evaluated findings and "tollarsjuka". However, further investigations are needed in order to characterize the disease.”Tollarsjuka” är en sjukdom som sedan flera år blivit allt vanligare inom rasen Nova Scotia duck tolling retriever. Sjukdomen tycks vara av autoimmun karaktär, men bakgrunden är ännu oklar. Hundarna visar en varierande symtombild, men det ger sig ofta uttryck i form av hälta, stelhet, led- och muskelsmärta samt feber. Syftet med studien var att sammanställa journaler från hundar med misstänkt ”tollarsjuka”. Patienterna som ingår i studien är 18 privatägda tollare. Den dominerande symtombilden bland de undersökta tollarna är problem med trötthet, hälta och stelhet. Röntgenundersökning av smärtande leder samt undersökning av ledvätska från två hundar indikerar att det är en immunmedierad, icke erosiv artrit som drabbar hundarna. Blodprovsundersökningar visar hos ett fåtal hundar lindriga hematologiska förändringar som tycks ha liten betydelse för utvecklingen av ”tollarsjuka”. Vid elektrofores av proteinfraktionen i blodet har sex av 12 hundar lindrigt sänkta albuminvärden. Detta skulle kunna vara tidiga symtom på glomerulinefrit, som kan ses hos hundar med systemiska, autoimmuna sjukdomar

Multi-scale dissolution dynamics for carbon sequestration in carbonate rock samples

Carbon dioxide (CO2) sequestration in porous, sedimentary reservoirs is a key technology to mitigate emissions of anthropogenic CO2 and curb irreversible climate change. The abundance of carbonate formations, both as saline aquifers and hydrocarbon reservoirs, makes future CO2 storage in carbonate formations highly likely. The weak carbonic acid that forms when CO2 dissolves in water will, however, interact with highly reactive carbonate. Preferential flow paths may form during dissolution or calcite precipitation may reduce injectivity - both processes significantly impacting reservoir sweep efficiency. Hence, understanding the dynamics of the dissolution processes and their influence on flow properties is necessary to safely store CO2 in carbonate formations. Darcy and sub-Darcy scale dissolution kinetics were here assessed in carbonate core plugs with and without pre-existing highly permeable pathways, during multiphase flow and under relevant storage conditions. Darcy-scale dissolution and precipitation data (injectivity changes, effluent analysis and mass loss) confirmed that CO2 and brine co-injections altered the carbonate rock structure on Darcy scale, but could not determine the cause of change. Multi-modal imaging was applied to independently quantify structural changes with computed tomography (CT) and aqueous flow characteristics with positron emission tomography (PET), thereby determining injectivity dependence on local flow patterns. Formation of high permeability pathways, which was expected due to rock dissolution, was only observed in cores with pre-existing open fractures, where reactive flow was limited to the fracture plane. A good correlation between the two imaging modules was found: areas of higher porosity yielded a low-density CT signal (i.e. high number of voids present) and a high PET signal density (i.e. large volume of traced fluid present). Loss of injectivity suggested local changes in the flow pattern due to blocking of pore throats by moving particles or secondary precipitation or mineralization of dissolved ions. High-resolution PET imaging revealed cementation, that was also visible using micro-CT, hence determining sub-Darcy local flow obstructions that led to decreased Darcy scale injectivity. Multi-modal imaging, where core characteristics, such as large vugs and cementation, can be independently determined by complementary modalities, may therefore be a useful tool to quantify reactive flow and resulting dissolution in rock samples.publishedVersio

Skeletal Characterization of Smurf2-Deficient Mice and In Vitro Analysis of Smurf2-Deficient Chondrocytes

Overexpression of Smad ubiquitin regulatory factor 2 (Smurf2) in chondrocytes was reported to cause spontaneous osteoarthritis (OA) in mice. However, it is unclear whether Smurf2 is involved in bone and cartilage homeostasis and if it is required for OA pathogenesis. Here we characterized age-related changes in the bone and articular cartilage of Smurf2-deficient (MT) mice by microCT and histology, and examined whether reduced Smurf2 expression affected the severity of OA upon surgical destabilization of the medial meniscus (DMM). Using immature articular chondrocytes (iMAC) from MT and wild-type (WT) mice, we also examined how Smurf2 deficiency affects chondrogenic and catabolic gene expressions and Smurf2 and Smurf1 proteins upon TGF-β3 or IL-1β treatment in culture. We found no differences in cortical, subchondral and trabecular bone between WT and MT in young (4 months) and old mice (16-24 months). The articular cartilage and age-related alterations between WT and MT were also similar. However, 2 months following DMM, young MT showed milder OA compared to WT (~70% vs ~30% normal or exhibiting only mild OA cartilage phenotype). The majority of the older WT and MT mice developed moderate/severe OA 2 months after DMM, but a higher subset of aged MT cartilage (27% vs. 9% WT) remained largely normal. Chondrogenic gene expression (Sox9, Col2, Acan) trended higher in MT iMACs than WT with/without TGF-β3 treatment. IL-1β treatment suppressed chondrgenic gene expression, but Sox9 expression in MT remained significantly higher than WT. Smurf2 protein in WT iMACs increased upon TGF-β3 treatment and decreased upon IL-1β treatment in a dose-dependent manner. Smurf1 protein elevated more in MT than WT upon TGF-β3 treatment, suggesting a potential, but very mild compensatory effect. Overall, our data support a role of Smurf2 in regulating OA development but suggest that inhibiting Smurf2 alone may not be sufficient to prevent or consistently mitigate post-traumatic OA across a broad age range

Proliferation and patterning are mediated independently in the dorsal spinal cord downstream of canonical Wnt signaling

AbstractCanonical Wnt signaling can regulate proliferation and patterning in the developing spinal cord, but the relationship between these functions has remained elusive. It has been difficult to separate the distinct activities of Wnts because localized changes in proliferation could conceivably alter patterning, and gain and loss of function experiments have resulted in both types of defects. To resolve this issue we have investigated canonical Wnt signaling in the zebrafish spinal cord using multiple approaches. We demonstrate that Wnt signaling is required initially for proliferation throughout the entire spinal cord, and later for patterning dorsal progenitor domains. Furthermore, we find that spinal cord patterning is normal in embryos after cell division has been pharmacologically blocked. Finally, we determine the transcriptional mediators of Wnt signaling that are responsible for patterning and proliferation. We show that tcf7 gene knockdown results in dorsal patterning defects without decreasing the mitotic index in dorsal domains. In contrast, tcf3 gene knockdown results in a reduced mitotic index without affecting dorsal patterning. Together, our work demonstrates that proliferation and patterning in the developing spinal cord are separable events that are regulated independently by Wnt signaling

Allergic Disorders in Africa and Africans: Is it Primarily a Priority?

In Africa, the burden of some diseases has been a problem for centuries. The spectrum of African diseases includes allergies, infections, nutritional deficiencies, and natural disasters. Efforts made by scientists to search for possible means of disease control have been outstanding; however, in some infections, solutions are still out of reach. In disease control programs, it might be worthwhile to pay attention to the most striking diseases than merely follow a holistic approach. This short review tackles the problems of allergy and allergens in Africa as compared with other disease burdens that may suggest the need for a more balanced approach based on priority

Brachioradial pruritus in a patient with cervical disc herniation and Parsonage-Turner syndrome

Brachioradial pruritus is a chronic sensory neuropathy of unknown etiology which affects the skin of the shoulders, arms and forearms on the insertion of the brachioradialis muscle. We describe the case of a 60-year old woman recently diagnosed with multiple myeloma who refers paresis, severe pruritus and itching lesions on the right arm with 6 months of evolution. Investigation led to a diagnosis of Brachioradial pruritus consequent to the presence of cervical disc herniation and Parsonage-Turner syndrome. The patient started gabapentin 900 mg/day with good control of itching. Corticosteroids and antihistamines are often ineffective in the treatment of BP. Gabapentin has been used with encouraging results. All patients with Brachioradial pruritus should be evaluated for cervical spine injuries

Hva arbeider tidligere IT-studenter ved Høgskolen i Østfold med, og hvor relevant har utdanningen deres vært for nåværende jobbsituasjon?

Artikkelen beskriver resultatene fra en undersøkelse som er gjort våren 2017 blant IT-studentene som avsluttet ved Høgskolen i Østfold 2011-2016. Temaene som ble tatt opp omfattet • søkeprosessen/hvordan og hvor raskt studentene fikk jobb • jobbinnhold / hva arbeider de tidligere studentene med • sammenhengen mellom studier og jobbinnhold • for de studentene som ikke fullførte: hva var årsaken til at de ikke fullførte IT-studiet. Undersøkelsen har både en kvantitativ del og en kvalitativ del. Metodisk bygger den både på kategoriseringer som er gjort fra en av bransjeforeningene (IKT-Norge) og på ulike studentundersøkelser (NOKUT, NIFU), og det gjøres en kort sammenligning med disse. Det er også gjort andre metodiske grep som beskrives. Undersøkelsen viser at de aller fleste som svarte fikk jobb fort (0-3 måneder). Funnene indikerer dermed studiets relevans for senere jobbsituasjon. Svarene viser en sterk sammenheng mellom HiØs studier og de ulike fagområdene som respondentene jobber med. Ser vi på de ulike fagområdene innen IT, uavhengig av retning, scorer programmering, databaser og prosjektarbeide/ledelse høyest, men også systemarkitektur, support og systemdrift. De 4 IT-Bachelor-studiene som studeres har en faglig bredde, fra vekt på IT-teknisk via programmering til IT-organisasjon og næringsliv og medieproduksjon. Vi finner et klart samsvar mellom de ulike studiene og hvilke typer IT-jobber som studentene får etterpå. Generelt viser funnene også at studiene var «Litt relevant» eller «Svært relevant» (de to høyeste kategoriene, som til sammen hadde 78%, likt fordelt mellom disse to). Tilsvarende studeres relevans av enkeltfag, både direkte nyttig og nyttig som bakgrunn. For de som ikke fullførte, ser vi at det for de fleste var personlige grunner som var den viktigste årsaken til at de avsluttet studiet underveis. Totalt sett gir resultatene ny innsikt i sammenhengen mellom IT-studier og jobbinnhold, noe som kan være nyttig både for høgskoler/universiteter og for arbeidsliv.publishedVersio