Computer Application to Estimate PVT Conditions in Oil Wells in the Ecuadorian Amazon

A reservoir behaviour's characterisation is determined by analysing the fluids' physical properties, reported in Pressure, Volume and Temperature (PVT) tests. These tests are performed in the laboratory or are estimated by mathematical correlations with the well's basic properties. The eastern basin of Ecuador is considered a hydrocarbon zone, and the analysis of the physical properties of the fluid from oil wells is essential. The aim is to develop the PVTTESTSYSTEM software to estimate PVT conditions when there are no laboratory tests. The study methodology is based on (i) Compilation of 10 PVT laboratory tests of oil wells in the eastern basin of Ecuador; (ii) Analysis of mathematical correlations; (iii) Development of the PVTTESTSYSTEM software, with the wells' initial conditions' input, selecting the mathematical correlation and estimation of results, based on the relationship of the properties of oil and gas; iv) Comparison of data obtained by laboratory tests and PVTTESTSYSTEM software reports. The software used with a graphical interface presents a registration and login platform and five modules that allow: inserting company and field data, initial oil well data, selecting correlations, calculating PVT properties and generating a graphic report. The results show that the mathematical correlations that estimate PVT properties were systematised, which approximate the laboratory tests' real results. The approximation of the calculated results with the actual results establishes a high confidence level for the PVTTESTSYSTEM software.

Sedimentary response to current and nutrient regime rearrangement in the Eastern Mediterranean Realm during the early to middle Miocene (southwestern Cyprus)

During the early and middle Miocene, the Mediterranean had become a restricted marginal marine sea with diminishing and ultimate loss of connectivity to the Indian Ocean. This dramatically changed the heat, energy, freshwater and nutrient budgets across the Mediterranean and most notably in its eastern basin. While one of the most prominent lines of evidence of this change in the Eastern Mediterranean is the onset of sapropel formation, many other aspects of the sedimentary system changed in response to this rearrangement. Here we present a detailed analysis of a hemipelagic succession from southeastern Cyprus dated to the late Aquitanian to the early Serravallian (22.5 – 14.5 Ma). This sequence is carbonate-dominated and formed during the decoupling of the Mediterranean Sea and the Indian Ocean. It exhibits sedimentation with mass transport contribution from shallow water carbonates to deeper facies with phosphatization and bottom current (at intermediate depth) interactions. This succession traces both local subsidence and loss of a local carbonate factory. Additionally, it records a shift in bottom current energy and seafloor ventilation, which are an expected outcome of connectivity loss with the Indian Ocean.

Empires of Xolotl: Two Opening Compositions of the Codex Xolotl

Only one of two opening compositions in the Codex Xolotl has been recognized. The conventional version shows the entry of Xolotl, Nopaltzin, and six lesser rulers into the Basin of Mexico from near Tula, Hidalgo, followed by settlement at Xoloc and later a place that will become Tenayuca. The manuscript’s two larger fragments, assembled correctly for the first time, show Xolotl and Nopaltzin observing and moving across a more settled eastern basin into regions to the south ranging from Puebla to Morelos, notably including Cuernavaca. At the same time, they and their six followers are shown settled among caves in the western basin around the future Tenayuca. The two Chichimecs attract fellow Chichimecs from the Cuernavaca region to the Tepetlaoztoc region and trouble ensues. These two realizations of a Chichimec vision of empire are well recorded by the remarkable Aztec graphic communication system. Its portrayal of changes to different ways of life over the centuries reveals an interplay of an oral gathering and hunting culture with a settled society, recording the Chichimec experience and their own way of life with their combined oral and graphic system. Elements of the Chichimecs’ visions of empire endure throughout the Codex Xolotl as its messaging power shines across the contact period and into early colonial times.

Large- and small-scale movement and distribution of acoustically tagged lake sturgeon (Acipenser fulvescens) in eastern Lake Erie

Background Defining the spatial distribution, home range, and movement patterns of lake sturgeon (Acipenser fulvescens) is important to managers and decision-makers given the large migration potential and potamodromous behavior exhibited by the species. A remnant population of lake sturgeon remains in the far eastern basin of Lake Erie and although recent efforts have estimated the population size, described the age distribution, and identified a primary spawning site no study to date has examined the spatial distribution or movements of individuals within this population. Between 2014 and 2018, we acoustically tagged 59 adult lake sturgeon, captured in the Buffalo Harbor area, and monitored their large-scale movements throughout Lake Erie with the Great Lakes Acoustic Telemetry System and small-scale movements with a Vemco Positioning System in the Buffalo Harbor area. After dividing Lake Erie into seven sections, we ran a multi-state mark–recapture model to examine the movement rates into and out of the eastern most section of the lake. Within a heavily utilized lake section, in the Buffalo Harbor area, we identified home ranges with our Vemco Positioning System for each season and year using averaged Brownian bridge movement models. Results Although some sturgeon demonstrated large-scale movements, traversing the entirety of Lake Erie, the majority of individuals spent their time in the eastern basin of the lake. Home ranges appeared to vary among seasons, but were consistent across years with lake sturgeon selecting the northeastern, rocky, and shallow area of our array during pre-spawning and spawning seasons and leaving our array, or selecting a trough running along the northwestern portion of our array comprising sand and bedrock, in the summer and fall seasons. Conclusions Documenting these large-scale movements aligns with previous findings that lake sturgeon on either end of the lake are genetically similar and demonstrates lake sturgeon in the eastern basin exhibit strong philopatry. Our small-scale movement models provide managers with spatial reference points, in the form of utilization distributions, indicating heavily used areas by lake sturgeon within seasons. Future studies should examine what parameters are driving site selection in these areas.

Large- and small- scale movement and distribution of acoustically tagged lake sturgeon (Acipenser fulvescens) in eastern Lake Erie

Background Defining the spatial distribution, home range, and movement patterns of lake sturgeon (Acipenser fulvescens) is important to managers and decision makers given the large migration potential and potamodromous behavior exhibited by the species. A remnant population of lake sturgeon remains in the far eastern basin of Lake Erie and although recent efforts have estimated the population size, described the age distribution, and identified a primary spawning site no study to date has examined the spatial distribution or movements of individuals within this population. Between 2014 and 2018 we acoustically tagged 59 adult lake sturgeon, captured near the headwaters of the Niagara River, and monitored their large-scale movements throughout Lake Erie with the Great Lakes Acoustic Telemetry System and small-scale movements with a Vemco Positioning System near the headwaters of the Niagara River. After dividing Lake Erie into seven sections, we ran a multi-state mark recapture model to examine the movement rates into and out of the eastern most section of the lake. Within a heavily utilized lake section, near the headwaters of the Niagara River, we identified home ranges with our Vemco Positioning System for each season and year using averaged Brownian bridge movement models.Results Although some sturgeon demonstrated large-scale movements, traversing the entirety of Lake Erie, the majority of individuals spent their time in the eastern basin of the lake. Home ranges appeared to vary among seasons but were consistent across years with lake sturgeon selecting the northeastern, rocky, and shallow area of our array during pre-spawning and spawning seasons and leaving our array, or selecting a trough running along the northwestern portion of our array comprised of sand and bedrock, in the summer and fall seasons. Conclusions Documenting these large-scale movements aligns with previous findings that lake sturgeon on either end of the lake are genetically similar and demonstrates lake sturgeon in the eastern basin exhibit strong philopatry. Our small-scale movement models provide managers with spatial reference points, in the form of utilization distributions, which are heavily used by lake sturgeon within seasons. Future studies should examine what parameters are driving site selection in these areas.

A 2011-2018 Fukushima Perspective on North Pacific Mode Water Pathways

<p>This investigation uses the tracer information provided by the 2011 direct ocean release of radio-isotopes, (<sup>137</sup>Cs, ~30-year half-life and <sup>134</sup>Cs, ~2-year half-life) from the Fukushima Dai-ichi nuclear power plant (FDNPP) together with hydrographic profiles to better understand the origins and pathways of mode waters in the North Pacific Ocean. While using information provided by radionuclide observations taken from across the basin, the main focus is on the eastern basin and results from analyses of two data sets 2015 (GO-SHIP) and 2018 (GEOTRACES) along the 152°W meridian. The study looks at how mode waters formed in the spring of 2011 have spread and mixed, and how they have not. Our radiocesium isotope samples tell a story of a surprisingly confined pathway for these waters and suggest that circulation to the north into the subpolar gyre occurs more quickly than circulation to the south into the subtropical gyre. They indicate that in spite of crossing 6000 km in their journey across the Pacific, the densest 2011 mode waters stayed together spreading by only a few hundred kilometers in the north/south direction, remained subsurface (below ~200 m) for most of the trip, and only saw the atmosphere again as they followed shoaling density surfaces into the boundary of the Alaska Gyre. The more recent data are sparse and do not allow direct measurement of the FDNPP specific <sup>134</sup>Cs, however they do provide some information on mode water evolution in the eastern North Pacific seven years after the accident. </p>

Variability of the hydrological characteristics of the Eastern Mediterranean over the last decade

<p><span>A hydrodynamic simulation is carried out over the entire Mediterranean basin at a resolution of 3 to 4 km and a duration of about 10 years (2011-2020). The results are systematically evaluated using Argo profiles focusing on the spatial distribution of water mass properties along their path, the main mesoscale structures, the mean vertical temperature and salinity profiles by sub-basins as well as their "pseudo temporal evolution" biased by the variability of the spatial and temporal distribution of Argo observations.</span></p><p><span>The simulation has generally very low mean biases (of the order of 0.01 for salinity) and correlations on the monthly time series reconstructed from the observations, of the order of 0.9 at the scale of the eastern basin, both in surface waters and at 200 m in intermediate waters. </span></p><p><span>The evolution of salinity over the decade is then analyzed from the simulation. Particular attention is paid to the main basins of water mass formation, the Adriatic, the Levantine basin and the South Aegean Sea. The factors driving this evolution are analyzed in each of these basins. The propagation of the changes from these formation areas to the entire eastern basin is then examined, with a particular focus on the intermediate waters. </span></p>

ECOSYSTEMS STATE OF EASTERN AND WESTERN BASINS OF SAKSKOE LAKE (CRIMEAN REPUBLIC)

Sakskoe Lake is the most thoroughly studied water body in Crimea. Its therapeutic mud and brine are exploited by balneological treatment methods. During the two centuries, when the lake was used by humans, it was subdivided into seven water bodies by dams, with two of these bodies (Eastern and Western) being now utilized for medical purposes, and the other five being protective. The Eastern (currently exploited) basin is now used to produce therapeutic mud and brine. The bottoms of the saline basins are covered by sediments: an upper layer of black silt, which is underlain by gray, steel-gray, occasionally bluish silt, which is used as therapeutic mud. The lake is fed by surface and groundwaters. Retaining dams and flood embankments erected in nearby ravines preclude desalination of the lake with flood and rain waters. Seawater is pumped to the lake through channels to preclude its drying. A quay is now actively constructed around the lake and will likely notably affect its hydrological and ecological conditions. The aim of the present study was the comparative analysis of the chemical and physical characteristics of the Eastern and Western basins of the Sakskoe Lake at the period of intensive building activity on their coasts at the summer period of 2019. Brine samples were collected at two tested sites in each of the lakes. Water salinity was measured by a PAL-06S LTA GO (Japan) refractometer and was expressed in ‰. The pH and Eh of the waters and oxygen dissolved in them were determined in the laboratory by an Expert-001 (Econix-Expert Moexa CoLtd, Russia) analyzer, with the use of appropriate Volta (Russia) selective electrodes. Ions concentration was determined spectrophotometrically and by atomic absorption method. Various living stages of Artemia populations in two water bodies were studied according the standard microscopic methods. The obtained results demonstrated, that the total content of the cations in the brine of the Western basin was in 1,5-fold higher as compared with the data of the brine in the Eastern basin (108,4 and 71,2 g/l respectively). The values were directly correlated with the high salinity of the Western basin brine. The identical trend was shown for the anions concentration, which was significantly greatly in the Western basin related to Eastern one (193,14 and 125,41 g/l correspondingly), which was connected with the different hydrogeological conditions of the formation of the ecosystems of the tested water bodies. At the other hand, pH, salinity and Eh of the brine in the Eastern basin were lower than in the brine of the Western basin, while the concentration of dissolved oxygen was higher. In the brine of the Eastern basin of the lake all living stages of Artemia, including cysts, nauplia and adults were found, while in the Western basin only cysts were shown. Therefore, according the obtained results we could suggest, that anthropogenic processes which were taken place on the coasts of the Sakskoe Lake accompanied with the intensive building activity did not influence on the lake ecosystem. The further monitoring studies including the testing of the ions concentrations in the brine of two basins, Artemia populations state are required for the understanding the changes of the both ecosystems and the possible reasons of their changes. It is important for development of the optimization of the management of Sakskoe lake and its resources exploitation.