scholarly journals Data-Driven Modeling Approach for Pore Pressure Gradient Prediction while Drilling from Drilling Parameters

ACS Omega ◽  
2021 ◽  
Author(s):  
Ahmed Abdelaal ◽  
Salaheldin Elkatatny ◽  
Abdulazeez Abdulraheem
Author(s):  
Shams Kalam ◽  
Rizwan Ahmed Khan ◽  
Shahnawaz Khan ◽  
Muhammad Faizan ◽  
Muhammad Amin ◽  
...  

Author(s):  
K. Midzodzi Pekpe ◽  
Djamel Zitouni ◽  
Gilles Gasso ◽  
Wajdi Dhifli ◽  
Benjamin C. Guinhouya

2017 ◽  
Vol 13 (7) ◽  
pp. e1005627 ◽  
Author(s):  
Warren D. Anderson ◽  
Danielle DeCicco ◽  
James S. Schwaber ◽  
Rajanikanth Vadigepalli

AIAA Journal ◽  
2021 ◽  
pp. 1-13
Author(s):  
Sean T. Kelly ◽  
Andrea Lupini ◽  
Bogdan I. Epureanu

2021 ◽  
Author(s):  
Nikolay Baryshnikov ◽  
Evgeniy Zenchenko ◽  
Sergey Turuntaev

<p>Currently, a number of studies showing that the injection of fluid into the formation can cause induced seismicity. Usually, it is associated with a change in the stress-strain state of the reservoir during the pore pressure front propagation. Modeling this process requires knowledge of the features of the filtration properties of reservoir rocks. Many researchers note the fact that the measured permeability of rock samples decreases at low pressure gradients. Among other things, this may be due to the formation of boundary adhesion layers with altered properties at the interfaces between the liquid and solid phases. The characteristic thickness of such layer can be fractions of a micron, and the effect becomes significant when filtering the fluid in rocks with a comparable characteristic pore size. The purpose of this work was to study the filtration properties of rock samples with low permeability at low flow rates. Laboratory modeling of such processes is associated with significant technical difficulties, primarily with the accuracy limit of measuring instruments when approaching zero speed values. The technique used by us to conduct the experiment and data processing allows us to study the dependence of the apparent permeability on the pore pressure gradient in the range of 0.01 MPa/m, which is comparable to the characteristic pressure gradients during the development of oil fields. In the course of the study, we carried out laboratory experiments on limestone core samples, during which the dependencies of their apparent permeability on the pore pressure gradient were obtained. We observed a significant decrease in their permeability at low flow rates. In the course of analyzing the experimental results, we proposed that a decrease in apparent permeability may occur due to the effect of even a small amount of residual gas in the pore space of the samples. This has been confirmed by additional experiments. The possibility of clogging of core sample pore space must be considered when conducting when conducting laboratory studies of the core apparent permeability.</p>


Geosciences ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 17 ◽  
Author(s):  
Ziyang Li ◽  
Wei Ye ◽  
Miroslav Marence ◽  
Jeremy Bricker

Climate change with extreme hydrological conditions, such as drought and flood, bring new challenges to seepage behavior and the stability of earthfill dams. Taking a drought-stricken earthfill dam of China as an example, the influence of drought-flood cycles on dam seepage behavior is analyzed. This paper includes a clay sample laboratory experiment and an unsteady finite element method seepage simulation of the mentioned dam. Results show that severe drought causes cracks on the surface of the clay soil sample. Long-term drought causes deeper cracks and induces a sharp increase of suction pressure, indicating that the cracks would become channels for rain infiltration into the dam during subsequent rainfall, increasing the potential for internal erosion and decreasing dam stability. Measures to prevent infiltration on the dam slope surface are investigated, for the prevention of deep crack formation during long lasting droughts. Unsteady seepage indicators including instantaneous phreatic lines, equipotential lines and pore pressure gradient in the dam, are calculated and analyzed under two assumed conditions with different reservoir water level fluctuations. Results show that when the water level changes rapidly, the phreatic line is curved and constantly changing. As water level rises, equipotential lines shift upstream, and the pore pressure gradient in the dam’s main body is larger than that of steady seepage. Furthermore, the faster the water level rises, the larger the pore pressure gradient is. This may cause internal erosion. Furthermore, the case of a cracked upstream slope is modelled via an equivalent permeability coefficient, which shows that the pore pressure gradient in the zone beneath the cracks increases by 5.9% at the maximum water level; this could exacerbate internal erosion. In addition, results are in agreement with prior literature that rapid drawdown of the reservoir water level is detrimental to the stability of the upstream slope based on embankment slope stability as calculated by the Simplified Bishop Method. It is concluded that fluctuations of reservoir water level should be strictly controlled during drought-flood cycles; both the drawdown rate and the fill rate must be regulated to avoid the internal erosion of earthfill dams.


2013 ◽  
Author(s):  
Peter John Dzurman ◽  
Juliana Yuk Wing Leung ◽  
Stefan David Joseph Zanon ◽  
Ehsan Amirian

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