Use of concentric hele-shaw cell for the study of displacement flow and interface tracking in primary cementing

We present our new designed concentric Hele-Shaw cell geometry with dynamic similarity to a real field wellbore annulus during primary cementing, and then, the results of displacement flow of Newtonian and yield-stress non-Newtonian fluids in it are described. The displacement stability and efficiency, the effect of back, front, and side boundaries on displacement, bypassing pockets of displaced yield-stress fluid in displacing fluid, and the behavior of pressure gradients in the cell are investigated. Applications of intermediate buoyant particles with different sizes and densities intermediate between those of successively pumped fluids for tracking the interface between the two displaced and displacing fluids are examined. The main idea is to upgrade this concentric Hele-Shaw cell geometry later to an eccentric one and check the possibility of tracking the interface between successive fluids pumped in the cell. Successful results help us track the interface between drilling fluid and spacer/cement during primary cementing in wells penetrating a CO2 storage reservoir and decreasing the risk of CO2 leakage from them.publishedVersio

Cuttings transport with oil- and water-based drilling fluids

Deviated well sections are common in modern well construction. In mature areas like the North Sea region, practically all producers or injector wells will have highly deviated sections. These wells must be drilled and completed in an optimal manner with respect to drill time, cost, risk and functionality. Most cuttings transport and hydraulic models are developed based on tests with model fluids and often in small diameter test sections. Hole cleaning properties and hydraulic behaviour of field fluids differ from those of most model fluids. Furthermore, results from small diameter tests may not always be relevant for, nor scalable to, field applications due to time, length and other scale differences. Hence, there is a need for studies in controlled laboratory environments with various field application designed drilling fluids to improve engineering models and practices. This paper presents results from laboratory tests using field applied fluids. The drilling fluids have similar density and viscosity within the relevant shear rate range applied during drilling operations and in the tests. One of the fluids is oil-based and the other one is an inhibitive water-based drilling fluid.acceptedVersio

Wet Drilled Cuttings Bed Rheology

The cuttings transport efficiency of various drilling fluids has been studied in several approaches. This is an important aspect, since hole cleaning is often a bottleneck in well construction. The studies so far have targeted the drilling fluid cuttings’ transport capability through experiments, simulations or field data. Observed differences in the efficiency due to changes in the drilling fluid properties and compositions have been reported but not always fully understood. In this study, the cuttings bed, wetted with a single drilling fluid, was evaluated. The experiments were performed with parallel plates in an Anton Paar Physica 301 rheometer. The results showed systematic differences in the internal friction behaviors between tests of beds with oil-based and beds with water-based fluids. The observations indicated that cutting beds wetted with a polymeric water-based fluid released clusters of particles when external forces overcame the bonding forces and the beds started to break up. Similarly, it was observed that an oil-based fluid wetted bed allowed particles to break free as single particles. These findings may explain the observed differences in previous cutting transport studies.publishedVersio

Wet-granular rheology to measure cuttings-bed strength

Drilled cuttings-bed formation is a natural process during wellbore drilling operations, although it is not desired. To optimally remove the drilled cuttings out of the wellbore it is important to break the formed beds. Wet-granulated material such as the drilled cuttings behave differently depending on the applied stress and particle concentration, it can behave as solid when is at rest or under low energy input, or it can flow like a fluid when a certain energy is reached. Here it is studied how a wetting fluid can modify the motion and properties of the cuttings-bed by using powder rheology.publishedVersio

First case of chronic wasting disease in Europe in a Norwegian free-ranging reindeer

Chronic wasting disease (CWD) is a fatal contagious prion disease in cervids that is enzootic in some areas in North America. The disease has been found in deer, elk and moose in the USA and Canada, and in South Korea following the importation of infected animals. Here we report the first case of CWD in Europe, in a Norwegian free-ranging reindeer in Southern Norway. The origin of the disease is unknown. Until now a low number of cervids, and among them a few reindeer, have been tested for CWD in Norway. Therefore the prevalence of CWD is unknown.publishedVersio

Oil-based drilling fluid's cuttings bed removal properties for deviated wellbores

Results from cuttings transport tests in the laboratory using different field-applied oil-based drilling fluids with similar weight and varying viscosities are presented in this paper. The fluids are designed for highly deviated wells, and the cuttings transport performance at relevant wellbore inclinations was investigated. The experiments have been performed in a flow loop that consists of a 10-m-long test section with 50.4 mm (2″) diameter freely rotating steel drill string inside a 100-mm (≈4″) diameter wellbore made of cement. Sand particles were injected while circulating the drilling fluid through the test section. Experiments were performed at three wellbore inclinations: 48, 60, and 90 deg from vertical. The applied flow loop dimensions are designed so that the results are scalable to field applications; especially for the 12 ¼″and 8 ½″ sections. The selected setup provides correct shear rate ranges and similar Reynolds numbers to the field application when the same fluids are applied. Results show that hole cleaning abilities of the tested fluids vary significantly with well angle, drill string rotation, and flowrate. Results support field experience showing that low viscous fluids are more efficient than viscous fluids at higher flowrates and low drill string rotation. As well as per field experience, more viscous fluids are efficient in combination with high drill string rotation rates. The results show the effect of cuttings transport efficiency as a function of hydraulic frictional pressure drop, demonstrating methods to achieve a more optimal hydraulic design in the tested conditions. The key findings have direct relevance to drilling operations.publishedVersio

Experimental Bench-Scale Study on Cuttings-Bed Erosion in Horizontal Wells

Cuttings-beds formation while drilling wellbores is a common challenge, especially for horizontal wells, as drilled particles have higher area to be deposited and form cuttings-beds, which can cause several problems such as increased torque and drag, pipe sticking or pipe breakage, among others. Removal of the drilled cuttings is done by circulating a suitable drilling fluid through the wellbore. This paper presents results from laboratory tests with deposited cuttings-bed and the flow of a fluid to erode the bed. The simulated cuttings-bed is a 1 m long deposited sand-bed in a horizontal section. Three different types of fluids are being used in the tests. To investigate how the rheological properties can affect the erodibility of the cuttings-bed, water (as a Newtonian fluid), a xanthan gum solution, and a water-based drilling fluid prepared for an offshore field operation (as a non-Newtonian fluids) are applied. Ultrasound measurements together with differential bed weight have been used to analyze the fluid–bed interaction. Results have shown that the cuttings-bed is eroded by dune movement. Saltation and dragging of sand particles due to the fluid flow appear to create a crest and then avalanche them down. The different types of fluids undergo different shear rates from the same pump power as the viscosity changes, as well as flow rates dependency along the dune extent.publishedVersio

Long-Term Safety of Intraperitoneal Radio Transmitter Implants in Brown Bears (Ursus arctos)

Intraperitoneal radio transmitters have been widely used in free-ranging wild mammals, but there are no long-term studies on their biocompatibility or technical stability within the abdominal cavity of animals. Possible negative health effects may bias results from ecological studies on instrumented animals and raise concerns over animal welfare issues. The aim of this study was to evaluate the long-term technical stability and pathological effects of Telonics intraperitoneal very high frequency (VHF) radio transmitters in brown bears (Ursus arctos). We instrumented 305 individual bears with intraperitoneal VHF radio transmitters during a 19-year period. We surgically removed devices that had been in bears for 1–9 years and collected transmitters from animals that died 1–13 years after implantation. We took biopsies for histopathology from tissue encapsulating implants in live bears. Retrieved transmitters underwent a technical inspection. Of the 125 transmitters removed from live bears, 66 were free-floating in the peritoneal cavity [a mean (SD) of 3.8 (1.5) years after implantation], whereas 59 were encapsulated in the greater omentum [4.0 (1.8) years after implantation]. Histopathology of biopsies of the 1–15 mm thick capsules in 33 individuals showed that it consisted of organized layers of connective tissue. In one third of the bears, the inner part of the capsule was characterized by a foreign body reaction. We inspected 68 implants that had been in bears for 3.9 (2.4) years. The batteries had short-circuited four (5.9%) of these devices. This resulted in the death of two animals 10 and 13 years after implantation. In two other bears that underwent surgery, we found the short-circuited devices to be fully encapsulated within the peritoneal cavity 5 and 6 years after implantation. A significant proportion of the other 64 inspected implants showed serious technical problems, such as corrosion of metal parts or the batteries (50%), detachment of the end cap (11.8%), and erosion (7.4%) or melting (5.9%) of the wax coating. We conclude that the wax coating of the transmitters was not biocompatible, that the technical quality of the devices was poor, and that these implants should not be used in brown bears

Agrárpiaci Jelentések TEJ ÉS TEJTERMÉKEK

Magyarországon a nyerstej országos termelői átlagára 104,97 forint/kg volt 2014 májusában, 14 százalékkal haladta meg az egy évvel korábbit. A nyerstej kiviteli ára 99,52 forint/kg volt ugyanekkor, egy év alatt 7 százalékkal csökkent és 5 százalékkal maradt el a belpiaci ártól. A FAO májusi előrejelzése szerint a globális tejtermelés 2,1 százalékkal 783 millió tonnára nő 2014-ben az előző évihez képest. Az Egyesült Államok tejkibocsátása 2,4 százalékkal, Kínáé 2 százalékkal, az Európai Unióé 1,5 százalékkal emelkedhet. Az ife előrejelzése szerint az EU tejfelvásárlása a FAO projekciójánál nagyobb mértékben, 3 százalékkal nőhet az idén. A tej- és tejtermékek exportja (tejegyenértékben kifejezve) Új-Zélandon 4 százalékkal, az EU-ban és az USA-ban egyaránt 3 százalékkal bővülhet 2014-ben az egy évvel korábbihoz viszonyítva. Az ife elemzői szerint az EU-ban a készletek 2014 elején nagyon alacsony szintre süllyedtek, azonban a termelésbővülés hatására ismét emelkedhetnek. A vaj év végi zárókészlete 80 százalékkal, a sovány tejporé 111 százalékkal nőhet az idén az egy évvel korábbihoz viszonyítva. A világpiaci kereslet élénkülése és a magas készletszint miatt az EU a többlettermelését a világpiacon értékesítheti. Az EU sovány tejpor kivitele 14,5 százalékkal, a vajé 4 százalékkal, a sajté 2,5 százalékkal nő, míg a teljes tejporé 2 százalékkal csökken 2014-ben az előző évihez viszonyítva. Az EU sovány tejpor kivitelének erőteljes bővülését az okozza, hogy a magas vajárak sokkal jövedelmezőbbé teszik a sovány tejpor és a vaj termelését a teljes tejporhoz viszonyítva