scholarly journals High density of structurally controlled, shallow to deep water fluid seep indicators imaged offshore Costa Rica

2013 ◽  
Vol 14 (3) ◽  
pp. 519-539 ◽  
Author(s):  
Jared W. Kluesner ◽  
Eli A. Silver ◽  
Nathan L. Bangs ◽  
Kirk D. McIntosh ◽  
James Gibson ◽  
...  
Keyword(s):  
Costa Rica ◽  
Deep Water ◽  
High Density

scholarly journals High density of white-faced capuchins (Cebus capucinus) and habitat quality in the Taboga Forest of Costa Rica

2019 ◽  
Author(s):  
Elizabeth Tinsley Johnson ◽  
Marcela E. Benítez ◽  
Alexander Fuentes ◽  
Celia R. McLean ◽  
Ariek B. Norford ◽  
...  
Keyword(s):  
Costa Rica ◽  
Anthropogenic Disturbance ◽  
Tropical Dry Forest ◽  
Cebus Capucinus ◽  
High Density ◽  
Dry Forest ◽  
Primate Species ◽  
Tropical Dry Forests ◽  
Forest Fragments ◽  
Key Resources

ABSTRACTAcross the globe, primate species and habitats are threatened by human activity. This is especially true for species found in tropical dry forests, which are widely distributed and comprise diverse habitats that remain largely unprotected. Evidence suggests that some primate species endemic to tropical dry forests may be more sensitive to anthropogenic disturbance than others, but our ability to predict primate abundance in the face of disturbance also depends on the specific variables for each site. Here, we consider the factors that explain the high density of white-faced capuchins (Cebus capucinus) found in the Taboga Forest, Costa Rica, a relatively small fragment of tropical dry forest surrounded by agricultural fields. Our analyses suggest that, for capuchins (and potentially for mantled howler monkeys, Alouatta palliata), the size and disturbance of a forest fragment may matter less than the composition and availability of key resources, like above-ground water. Group sightings for both species were higher near permanent water sources, but group sightings did not vary between edge and interior forest. These findings help explain why some primate species can flourish even alongside anthropogenic disturbance and thus carry important implications for conservation efforts. Smaller forest fragments, like Taboga, may be able to support high densities of some species because they provide a mosaic of habitats and key resources that buffer adverse ecological conditions. Future studies will assess the extent to which primates in the Taboga Forest rely on the canals versus the river and will consider how the high density of capuchins in Taboga influences ranging patterns, home range overlap, and the frequency and intensity of intergroup encounters.RESEARCH HIGHLIGHTSHere we introduce a new white-faced capuchin study site in the Taboga Forest, Costa Rica, a fragmented tropical dry forest.Forest fragments like Taboga may support high primate densities because they provide a mosaic of habitats and key resources.

scholarly journals High density of white‐faced capuchins ( Cebus capucinus ) and habitat quality in the Taboga Forest of Costa Rica

2020 ◽  
Vol 82 (2) ◽  
Author(s):  
Elizabeth Tinsley Johnson ◽  
Marcela E. Benítez ◽  
Alexander Fuentes ◽  
Celia R. McLean ◽  
Ariek B. Norford ◽  
...  
Keyword(s):  
Costa Rica ◽  
Habitat Quality ◽  
Cebus Capucinus ◽  
High Density

Four new deep-water flabelligerid species from Pacific Costa Rica (Annelida, Sedentaria, Flabelligeridae)

Zootaxa ◽  
2020 ◽  
Vol 4885 (4) ◽  
pp. 560-578
Author(s):  
SERGIO I. SALAZAR-VALLEJO
Keyword(s):  
Costa Rica ◽  
Deep Water ◽  
Deep Sea ◽  
Type Species ◽  
Anterior Margin ◽  
Single Type ◽  
Methane Seeps ◽  
Morphological Pattern ◽  
Fourth Species ◽  
Benthic Sampling

The discovery of four undescribed flabelligerid species from deep-water in Pacific Costa Rica resulted in the restriction of Diplocirrus Haase, 1915. As currently understood, Diplocirrus and Pherusa Oken, 1807 are separated after their morphological pattern. The species belonging in Diplocirrus have two types of branchiae, poorly developed cephalic cages and multiarticulate neurochaetae, whereas Pherusa species have branchiae of one type, well-developed cephalic cages and completely anchylosed neurochaetae. Benthic sampling and processing usually damage cephalic cages and if chaetae are completely broken, one could regard specimens without them, when they actually have it, but lost after sieving. Sampling using Alvin deep-sea submarine at methane seeps off Costa Rica resulted in some well-preserved specimens, and some of them fall between these two genera because they have well developed cephalic cages, and multiarticulate neurochaetae. Saphobranchia Chamberlin, 1919, with Stylarioides longisetosa von Marenzeller, 1890, as type species, is herein reinstated for some species previously included in Diplocirrus, restricted. The transferred species, including three ones newly described herein, have branchiae of a single type, long cephalic cage and body chaetae, and neurochaetae basally anchylosed and medially and distally articulated; some species currently included in Diplocirrus described from Arctic or deep water sediments are transferred into it. A key to identify all species in Saphobranchia, and another key to identify species in the restricted Diplocirrus are also included. The three new Saphobranchia species are S. canela n. sp., S. ilys n. sp. and S. omorpha n. sp. The fourth species belongs in Lamispina Salazar-Vallejo, 2014, and it is herein described as L. polycerata n. sp. after the presence of some long papillae along anterior margin of chaetiger 1. 

scholarly journals Olive Ridley Sea Turtle Hatching Success as a Function of Microbial Abundance and the Microenvironment ofIn SituNest Sand at Ostional, Costa Rica

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Vanessa S. Bézy ◽  
Roldán A. Valverde ◽  
Craig J. Plante
Keyword(s):  
Organic Matter ◽  
Costa Rica ◽  
Hatching Success ◽  
Quantitative Polymerase Chain Reaction ◽  
Organic Matter Content ◽  
Sea Turtle ◽  
High Density ◽  
Microbial Abundance ◽  
Olive Ridley ◽  
Nesting Beaches

Sea turtle hatching success at mass nesting beaches is typically lower than at solitary nesting beaches, presumably due in part to high rates of microbial metabolism resulting from the large input of organic matter from turtle eggs. Therefore, we tested the hypothesis that hatching success varies across areas of the beach in conjunction with differences in the physical nest environment and microbial abundance of in situ olive ridley sea turtle nests at Ostional, Costa Rica. We marked natural nests in high-density, low-density, and tidal-wash nesting areas of the beach and monitored clutch pO2and temperature throughout the incubation period. We quantified hatching success and collected samples of nest sand during nest excavations. We quantified microbial abundance (bacteria and fungi) with a quantitative polymerase chain reaction (qPCR) analysis. Hatching success was lower in nests with lower pO2, higher temperatures, higher organic matter content, and higher microbial abundance. Our results suggest that the lower oxygen within the nest environment is likely a result of the high microbial abundance and rates of decomposition in the nest sand and that these factors, along with increased temperature of clutches in the high-density nesting area, are collectively responsible for the low hatching success at Ostional.

scholarly journals Role of sea-level change in deep water deposition along a carbonate shelf margin, Early and Middle Permian, Delaware Basin: implications for reservoir characterization

2015 ◽  
Vol 66 (2) ◽  
pp. 99-116 ◽  
Author(s):  
Shunli Li ◽  
Xinghe Yu ◽  
Shengli Li ◽  
Katherine A. Giles
Keyword(s):  
Sea Level ◽  
Deep Water ◽  
Sea Level Change ◽  
High Density ◽  
Sediment Supply ◽  
Delaware Basin ◽  
Level Change ◽  
Basin Floor ◽  
Net To Gross ◽  
System Tracts

Abstract The architecture and sedimentary characteristics of deep water deposition can reflect influences of sea-level change on depositional processes on the shelf edge, slope, and basin floor. Outcrops of the northern slope and basin floor of the Delaware Basin in west Texas are progressively exposed due to canyon incision and road cutting. The outcrops in the Delaware Basin were measured to characterize gravity flow deposits in deep water of the basin. Subsurface data from the East Ford and Red Tank fields in the central and northeastern Delaware Basin were used to study reservoir architectures and properties. Depositional models of deep water gravity flows at different stages of sea-level change were constructed on the basis of outcrop and subsurface data. In the falling-stage system tracts, sandy debris with collapses of reef carbonates are deposited on the slope, and high-density turbidites on the slope toe and basin floor. In the low-stand system tracts, deep water fans that consist of mixed sand/mud facies on the basin floor are comprised of high- to low-density turbidites. In the transgression and high-stand system tracts, channel-levee systems and elongate lobes of mud-rich calciturbidite deposits formed as a result of sea level rise and scarcity of sandy sediment supply. For the reservoir architecture, the fan-like debris and high-density turbidites show high net-to-gross ratio of 62 %, which indicates the sandiest reservoirs for hydrocarbon accumulation. Lobe-like deep water fans with net-to-gross ratio of 57 % facilitate the formation of high quality sandy reservoirs. The channel-levee systems with muddy calciturbidites have low net-to-gross ratio of 30 %.

Shale Stability Evaluation and Leakage Control of High Density Clay Free Brine Drilling Fluid

2020 ◽  
Vol 861 ◽  
pp. 395-400
Author(s):  
Cong Bing Chang ◽  
Yi Hang Zhang ◽  
Xu Hui Song
Keyword(s):  
Deep Water ◽  
Salt Water ◽  
Drilling Fluid ◽  
High Density ◽  
Stability Evaluation ◽  
Evaluation Test ◽  
The Stability ◽  
Fluid Design ◽  
Effect Test ◽  
Selection Of

In view of the particularity of deep-water thick rock reservoir, in order to deal with the problem of poor reservoir stability and serious loss of drilling fluid in the drilling fluid design of M oilfield, this paper has carried out the reservoir inhibitor optimization evaluation test for the salt resistant high-density drilling fluid which has been designed and optimized, and also carried out the appropriate selection of plugging materials and plugging effect test for the loss of salt gypsum layer. The results show that the stability of saturated salt water drilling fluid in the salt gypsum layer with shale can be effectively ensured by the combination of CPI and uhib inhibitors within 2%. At the same time, FloSeal, a new plugging agent for 1-2mm fractures, is selected, and its plugging loss capacity is stably controlled below 30ml.

scholarly journals Bed type and flow mechanism of deep water sub-lacustrine fan fringe facies: an example from the Middle Permian Lucaogou Formation in Southern Junggar Basin of NW China

2020 ◽  
Author(s):  
Xin Shan ◽  
Xing-He Yu ◽  
Lina Jin ◽  
Ya-Long Li ◽  
Cheng-Peng Tan ◽  
...  
Keyword(s):  
Deep Water ◽  
Junggar Basin ◽  
High Density ◽  
Middle Permian ◽  
Coarse Grained ◽  
Turbidity Currents ◽  
Depositional System ◽  
Lucaogou Formation ◽  
Flow Mechanisms ◽  
Hybrid Event

AbstractSubmarine or sub-lacustrine lobe deposits are important reservoirs, but the fan fringe deposits form heterogeneities within deep water fan deposits. Fan fringe facies records the complex sediment gravity flow types. By understanding of the bed types and flow mechanisms, we can identify the fan fringe deposit, which aids in the reconstruction of deep water fan and reservoir evaluations. The Jiucaiyuanzi and Dalongkou sections in the West Bogda Mountains preserve well-exposed 536-m and 171-m thick successions, respectively, of a deep water lacustrine depositional system from the Middle Permian Lucaogou Formation. Bed types of the Lucaogou Formation include high-density turbidite, low-density turbidite, incomplete Bouma-type turbidite, hybrid event beds, and slump deposits. The Lucaogou Formation is interpreted here as a fan fringe facies due to the thin bed thickness that characterize turbidites and hybrid event beds, as well as the predominance of the isolated sheet architecture. Previous studies suggest that these deposits were considered as deposited in a deep water setting due to the absence of wave-related structures. The presence of abundant mud clasts in massive medium-coarse grained sandstone beds reflects the significant erosional capability and interactions between high-density turbidity currents and lake floor. The fan fringe facies here contains amalgamated and thick-bedded homolithic facies (~ 30%) and thin-bedded heterolithic facies (~ 70%). The examination of the bed type is of wider significance for facies prediction and reservoir heterogeneity in the sub-lacustrine fan fringe facies.

High Density Gravel Packing Fluid for High-Temperature Deep Water Wells

2021 ◽  
Author(s):  
Mayur Deshpande ◽  
Shamit Rathi ◽  
Sumit Songire ◽  
Ravikant Belakshe ◽  
John Davis
Keyword(s):  
High Temperature ◽  
Deep Water ◽  
High Pressures ◽  
Elevated Temperatures ◽  
High Density ◽  
Carrier Fluid ◽  
Well Completion ◽  
Water Wells ◽  
Sand Control ◽  
Gravel Packing

Abstract Southeast offshore India reservoirs have high-temperature deep water wells with significantly high pressures and unconsolidated sandstone formations. Controlling sand production is a major issue from inception to well completion and throughout the life of the well. A high density brine is required due to the high bottom hole pressures, thus executing sand control operations using such a high density brine as the base fluid for the gravel pack carrier fluid combined with the elevated temperatures is a significant challenge. A case is presented where a high-density temperature-resistant gravel packing fluid was optimized for a BHT of 320°F using a high-density brine. Additionally, the pH of the fluid was crucial considering the significant presence of CO2 in the formation, which was anticipated to affect asset integrity due to corrosion at low pH. A biopolymer-based fluid with oxidizing breaker was required in 14.2 ppg potassium-cesium formate brine and 12.5 ppg potassium formate brine. The fluid required evaluation for rheology and stability at 320°F, and at a shear rate of 170 s-1 with two conditions of viscosity to be sustained in the range of 75- 150 cP and 150-250 cP for the initial four-hour duration. The same fluid, after four hours, was also required to be broken within fourteen days. The fluid with the optimized formulation in regard with stability and rheology was further required to pass an acceptable sand suspension of ≤ 5% settling. Finally, the optimized fluid was required to show negligible corrosion effects on the downhole metallurgies. The stability and rheology were studied using a HPHT concentric cylinder viscometer. The sand suspension and corrosion characteristics were studied using an HPHT autoclave. The same fluid was studied with an acid breaker as a contingency for wells without CO2-related issues. After an extensive study, 12.72 gal/Mgal liquid gel concentrate of biopolymer when hydrated in 14.2 ppg and 15.45 gal/Mgal liquid gel concentrate of biopolymer, when hydrated in 12.5 ppg, providing viscosity in the range of 150-250 cP with 3 gal/Mgal and 5 gal/Mgal oxidizing breaker were selected, respectively. The optimized formulations passed sand suspension and had a pH in the range of 8-10, which imparted negligible corrosion loss to chrome- and nickel-based metallurgies. At the same conditions, the fluid showed acceptable results with 20 gal/Mgal organic acid breaker where the pH was ≤ 7. The combination of a commonly used biopolymer and a mixed formate brine produced a thermally stable fluid with unconventional chemistry, applicable for high-temperature, high-density conditions. With further study, it is expected that the temperature limit of this fluid can be extended beyond 320°F. The formulation for potassium formate brine was also tested at using field scale equipment to check for ease of mixing, reproducibility of results and for determining friction values when pumped at a certain rate via shunts. The fluid was mixed with relative ease using standard batch mixers and replicated the properties that were determined on a lab scale. The fluid also depicted superior proppant carrying capacities and lower friction numbers than expected which would enable lowering of overall surface pressures and surface pumping requirements.

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