The lethal and sublethal responses ofgammarus pulexto stress: Sensitivity and sources of variation in an in situ bioassay

1991 ◽  
Vol 10 (10) ◽  
pp. 1331-1339
Author(s):  
Mark Crane ◽  
Lorraine Maltby
Keyword(s):  
Stress Sensitivity ◽  
Sources Of Variation ◽  
In Situ Bioassay

An in situ bioassay for estuarine environments using the microalgaPhaeodactylum tricornutum

2002 ◽  
Vol 21 (3) ◽  
pp. 567-574 ◽  
Author(s):  
Matilde Moreira Dos Santos ◽  
Ignácio Moreno-Garrido ◽  
Fernando Gonçalves ◽  
Amadeu M. V. M. Soares ◽  
Rui Ribeiro
Keyword(s):  
In Situ Bioassay

Experiment on Mechanical Properties and Seepage Capability of Deep Tight Sandstone Under True-Triaxial Stresses Environment

2021 ◽  
Author(s):  
Jiaying Li ◽  
Chunyan Qi ◽  
Ye Gu ◽  
Yu Ye ◽  
Jie Zhao
Keyword(s):  
Mechanical Properties ◽  
In Situ Stress ◽  
Stress Sensitivity ◽  
Stress Conditions ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
True Triaxial ◽  
Strain Behavior ◽  
Triaxial Stresses

Abstract The characteristics of seepage capability and rock strain during reservoir depletion are important for reservoir recovery, which would significantly influence production strategy optimization. The Cretaceous deep natural gas reservoirs in Keshen Gasfield in Tarim Basin are mainly buried over 5000 m, featuring with ultra-low permeability, developed natural fractures and complex in-situ stress states. However, there is no comprehensive study on the variation of mechanical properties and seepage capability of this gas reservoir under in-situ stress conditions and most studies on stress-sensitivity are conducted under conventional triaxial or uniaxial stress conditions, which cannot truly represent in-situ stress environment. In this work, Cretaceous tight sandstone in Keshen Gasfield was tested under true-triaxial stresses conditions by an advanced geophysical imaging true-triaxial testing system to study the stress-sensitivity and anisotropy of rock stress-strain behavior, porosity and permeability. Four groups of sandstone samples are prepared as the size of 80mm×80mm×80mm, three of which are artificially fractured with different angle (0°,15°，30°) to simulate hydraulic fracturing. The test results corresponding to different samples are compared to further reveal the influence of the fracture angle on rock mechanical properties and seepage capability. The samples are in elastic strain during reservoir depletion, showing an apparent correlation with fracture angles. The porosity decreases linearly with stress loading, where the decrease rate of effective porosity of fracture samples is significantly higher than that of intact samples. The permeabilities decrease exponentially and show significant anisotropy in different principal stress directions, especially in σH direction. The mechanical properties and seepage capability of deep tight sandstone are successfully tested under true-triaxial stresses conditions in this work, which reveals the stress-sensitivity of anisotropic permeability, porosity and stress-strain behavior during gas production. The testing results proposed in this paper provides an innovative method to analyse rock mechanical and petrophysical properties and has profound significance on exploration and development of tight gas reservoir.

scholarly journals Algal Periphyton Growth on Nutrient-Diffusing Substrates: An in situ Bioassay

Ecology ◽  
1985 ◽  
Vol 66 (2) ◽  
pp. 465-472 ◽  
Author(s):  
G. Winfield Fairchild ◽  
Rex L. Lowe ◽  
William B. Richardson
Keyword(s):  
In Situ Bioassay

scholarly journals Inter- and Intragranular Stress Determination with Kossel Microdiffraction in a Scanning Electron Microscope

2006 ◽  
Vol 524-525 ◽  
pp. 109-114 ◽  
Author(s):  
Raphaël Pesci ◽  
Karim Inal ◽  
Sophie Berveiller ◽  
Etienne Patoor ◽  
Jean Sébastien Lecomte ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Ccd Camera ◽  
Stress Sensitivity ◽  
In Situ Tests ◽  
Set Up ◽  
Line Patterns ◽  
Electron Back Scattered Diffraction ◽  
Scanning Electron

A Kossel microdiffraction experimental set up is under development inside a Scanning Electron Microscope (SEM) in order to determine the crystallographic orientation as well as the inter- and intragranular strains and stresses on the micron scale, using a one cubic micrometer spot. The experimental Kossel line patterns are obtained by way of a CCD camera and are then fully indexed using a home-made simulation program. The so-determined orientation is compared with Electron Back-Scattered Diffraction (EBSD) results, and in-situ tests are performed inside the SEM using a tensile/compressive machine. The aim is to verify a 50MPa stress sensitivity for this technique and to take advantage from this microscope environment to associate microstructure observations (slip lines, particle decohesion, crack initiation) with determined stress analyses.

Research on Stress Sensitivity of Low Permeability Sand Stone Reservoir

2011 ◽  
Vol 317-319 ◽  
pp. 2432-2435
Author(s):  
Yu Xue Sun ◽  
Fei Yao ◽  
Jing Yuan Zhao
Keyword(s):  
Plastic Deformation ◽  
In Situ Stress ◽  
Stress Sensitivity ◽  
Oil Field ◽  
Low Permeability ◽  
High Permeability ◽  
Permeability Changes ◽  
Loading And Unloading ◽  
Sandstone Reservoir

In the process of low-permeability sandstone reservoir exploitation, stress sensitivity takes place with the effective stress rises gradually, which will cause permeability decline. Allowing to the condition of in-situ stress, the study and experiment on the rock core in Jilin oil field Fuxin326 oil layer are presented. The experimental results show that the stress sensitivity of this oil layer is small; the regularity of permeability changes is in accordance with exponential function. The stress sensitivity of high permeability core is larger than that of low permeability core. Moreover, experimental and theoretical analysis shows that low permeability core has a larger permeability loss than high permeability core in loading and unloading process where elastic plastic deformation of rock will happen, which is the major reason that permeability loss can not return completely.

scholarly journals Ferns: Potential In-situ Bioassay Systems for Aquatic-Borne Mutagens

1976 ◽  
Vol 66 (2) ◽  
pp. 75 ◽  
Author(s):  
Edward J. Klekowski ◽  
David M. Poppel
Keyword(s):  
In Situ Bioassay
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