scholarly journals Reconciling the Long‐Term Relationship Between Reservoir Pore Pressure Depletion and Compaction in the Groningen Region

2019 ◽  
Vol 124 (6) ◽  
pp. 6165-6178 ◽  
Author(s):  
Jonathan D. Smith ◽  
Jean‐Philippe Avouac ◽  
Robert S. White ◽  
Alex Copley ◽  
Adriano Gualandi ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Pressure Depletion

scholarly journals The Research on Borehole Stability in Depleted Reservoir and Caprock: Using the Geophysics Logging Data

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Junliang Yuan ◽  
Jingen Deng ◽  
Yong Luo ◽  
Shisheng Guo ◽  
Haishan Zhang ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Oil And Gas ◽  
Geomechanical Model ◽  
Borehole Stability ◽  
In Situ Stresses ◽  
Pressure Depletion

Long-term oil and gas exploitation in reservoir will lead to pore pressure depletion. The pore pressure depletion will result in changes of horizontal in-situ stresses both in reservoirs and caprock formations. Using the geophysics logging data, the magnitude and orientation changes of horizontal stresses in caprock and reservoir are studied. Furthermore, the borehole stability can be affected by in-situ stresses changes. To address this issue, the dehydration from caprock to reservoir and roof effect of caprock are performed. Based on that, the influence scope and magnitude of horizontal stresses reduction in caprock above the depleted reservoirs are estimated. The effects of development on borehole stability in both reservoir and caprock are studied step by step with the above geomechanical model.

scholarly journals Erratum to: Long-term in situ monitoring at Dashgil mud volcano, Azerbaijan: a link between seismicity, pore-pressure transients and methane emission

2010 ◽  
Vol 99 (S1) ◽  
pp. 241-241 ◽  
Author(s):  
Achim Kopf ◽  
Georg Delisle ◽  
Eckhard Faber ◽  
Behrouz Panahi ◽  
Chingiz S. Aliyev ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Methane Emission ◽  
In Situ Monitoring ◽  
Mud Volcano ◽  
Pressure Transients

Long-term in situ monitoring at Dashgil mud volcano, Azerbaijan: a link between seismicity, pore-pressure transients and methane emission

2009 ◽  
Vol 99 (S1) ◽  
pp. 227-240 ◽  
Author(s):  
Achim Kopf ◽  
Georg Delisle ◽  
Eckhard Faber ◽  
Behrouz Panahi ◽  
Chingiz S. Aliyev ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Methane Emission ◽  
In Situ Monitoring ◽  
Mud Volcano ◽  
Pressure Transients

Hydromechanical response of a bedded argillaceous rock formation to excavation and water injection

2015 ◽  
Vol 52 (1) ◽  
pp. 1-17 ◽  
Author(s):  
A.D. Le ◽  
T.S. Nguyen
Keyword(s):  
Rock Mass ◽  
Pore Pressure ◽  
Damage Zone ◽  
Water Injection ◽  
Constitutive Relationship ◽  
Opalinus Clay ◽  
Anisotropic Plastic ◽  
Mont Terri ◽  
Excavation Damage

Opalinus clay is a candidate host formation for the geological disposal of nuclear wastes in Switzerland. The understanding of its long-term mechanical (M) and hydraulic (H) behaviour is an essential requirement for the assessment of its performance as a barrier against radionuclide transport. To study the HM response of Opalinus clay, a microtunnel, 13 m in length and 1 m in diameter, was excavated in that formation at the Mont Terri Underground Research Facility. The rock mass was equipped with sensors to measure the deformation and pore pressure in the rock mass during and after the excavation. A mathematical model that couples the equations of flow and mechanical equilibrium was developed to simulate the HM response of the rock mass. An anisotropic plastic constitutive relationship, based on a microstructure tensor approach, was incorporated in the model. Creep was also considered, as well as the anisotropy of permeability. It is shown that the model satisfactorily predicts the shape and extent of the excavation damage zone (EDZ), deformation, and pore pressure in the rock mass. It is also shown that anisotropy and creep play an important role in the HM response of the rock mass to excavation. The model was further used to simulate water injection tests performed at the test section in the microtunnel. The results show that EDZ, due to its high permeability, is a preferential groundwater flow path along the microtunnel.

scholarly journals Coda-Wave Based Monitoring of Pore-Pressure Depletion-driven Compaction of Slochteren Sandstone Samples from the Groningen Gas Field

2020 ◽  
Author(s):  
Reuben Zotz-wilson ◽  
Nikoletta Filippidou ◽  
Arjan Linden ◽  
Berend Antonie Verberne ◽  
Auke Barnhoorn
Keyword(s):  
Pore Pressure ◽  
Coda Wave ◽  
Gas Field ◽  
Pressure Depletion ◽  
Groningen Gas Field

Post-installation pore-pressure changes around spudcan and long-term spudcan behaviour in soft clay

2014 ◽  
Vol 56 ◽  
pp. 133-147 ◽  
Author(s):  
Jiang Tao Yi ◽  
Ben Zhao ◽  
Yu Ping Li ◽  
Yu Yang ◽  
Fook Hou Lee ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Soft Clay ◽  
Pressure Changes

The effect of pore pressure depletion and injection cycles on ultrasonic velocity and quality factor in a quartz sandstone

Geophysics ◽  
2007 ◽  
Vol 72 (2) ◽  
pp. E43-E51 ◽  
Author(s):  
P. Frempong ◽  
A. Donald ◽  
S. D. Butt
Keyword(s):  
Pore Pressure ◽  
Effective Stress ◽  
Axial Strain ◽  
Fluid Pressure ◽  
Porous Rocks ◽  
Confining Stress ◽  
Viscoelastic Deformation ◽  
Experimental Conditions ◽  
Pore Pressures ◽  
Pressure Depletion

Passing seismic waves generate transient pore-pressure changes that influence the velocity and attenuation characteristics of porous rocks. Compressional ultrasonic wave velocities [Formula: see text] and quality factors [Formula: see text] in a quartz sandstone were measured under cycled pore pressure and uniaxial strain conditions during a laboratory simulated injection and depletion process. The objectives were to study the influence of cyclical loading on the acoustic characteristics of a reservoir sandstone and to evaluate the potential to estimate pore-fluid pressure from acoustic measurements. The values of [Formula: see text] and [Formula: see text] were confirmed to increase with effective stress increase, but it was also observed that [Formula: see text] and [Formula: see text] increased with increasing pore pressure at constant effective stress. The effective stress coefficient [Formula: see text] was found to be less thanone and dependent on the pore pressure, confining stress, and load. At low pore pressures, [Formula: see text] approached one and reduced nonlinearly at high pore pressures. The change in [Formula: see text] and [Formula: see text] with respect to pore pressure was more pronounced at low versus high pore pressures. However, the [Formula: see text] variation with pore pressure followed a three-parameter exponential rise to a maximum limit whereas [Formula: see text] had no clear limit and followed a two-parameter exponential growth. Axial strain measurements during the pore-pressure depletion and injection cycles indicated progressive viscoelastic deformation in the rock. This resulted in an increased influence on [Formula: see text] and [Formula: see text] with increasing pore-pressure cycling. The value [Formula: see text] was more sensitive in responding to the loading cycle and changes in pore pressures than [Formula: see text]; thus, [Formula: see text] may be a better indicator for time-lapse reservoir monitoring than [Formula: see text]. However, under the experimental conditions, [Formula: see text] was unstable and difficult to measure at low effective stress.

Mitigating Well Construction Challenges of a Caspian Deepwater Exploratory Well: A Cementing Perspective

2021 ◽  
Author(s):  
Irfan Kurawle ◽  
Ansgar Dieker ◽  
Adriana Soltero ◽  
Svetlana Nafikova
Keyword(s):  
Pore Pressure ◽  
Long Term Effects ◽  
Lost Circulation ◽  
Well Integrity ◽  
Pore Pressure Prediction ◽  
Wellbore Strengthening ◽  
Selective Placement ◽  
Fracture Gradient ◽  
Comprehensive Modeling

Abstract BP returned to Caspian deepwater exploratory drilling in 2019. The exploration well was drilled on the Shafag-Asiman structure in water depths greater than 2,000 ft. Well challenges included high shallow water flow (SWF) risk with multiple re-spuds on the nearest offset, lost circulation due to complex wellbore geometry combined with a narrow pore and fracture gradient window, and uncertainty in pore pressure prediction in abnormally pressured formations with a new depositional model. In addition, a well total depth more than 23,000 ft, eight string casing design and bottom-hole pressures greater than 20,000 psi presented a truly modern-day challenge to well integrity. A six-month planning phase for the cementing basis of design concluded by delivering slurry designs capable of combating SWF, qualified by variable-speed rotational gel strength measurement. Engineered lost circulation with selective placement of wellbore strengthening materials in combination with cement and mechanical barriers to provide isolation and integrity for the life of the well. Exhaustive pilot testing to account for changes required a cement design based on pore pressure variation and comprehensive modeling for hydraulics, centralizer placement, and mud displacement. This was complemented by a custom centralizer testing process specifically designed to simulate forces exerted in wells with similar complexity. Long-term effects on cement were evaluated, not only for placement but also for future operations including pressure and temperature cycles during wellbore construction or abandonment.

Pore pressures around tunnels in clay

1992 ◽  
Vol 29 (5) ◽  
pp. 819-831 ◽  
Author(s):  
L. Samarasekera ◽  
Z. Eisenstein
Keyword(s):  
Finite Elements ◽  
Pore Pressure ◽  
Earth Pressure ◽  
Dimensionless Time ◽  
Element Analysis ◽  
Initial Stress Field ◽  
Long Term Stability ◽  
Pore Pressures ◽  
Overconsolidated Clays

The pore-pressure generation and dissipation around shallow tunnels excavated in both normally and overconsolidated clays are investigated. The influence of the diameter D, depth of cover to diameter ratio H/D, coefficient of earth pressure at rest K0, and strength and modulus variations with depth on pore-pressure generation are examined. The effects of immediate support on pore pressure are also studied by defining a quantity termed effective stiffness ratio (ESR). A two-dimensional, nonlinear finite element analysis is performed to obtain the pore-pressure generation behav-iour. Strength, modulus, initial stress field, and unloading due to excavation are reflected in this analysis. The pore-pressure dissipation behaviour is investigated by employing an uncoupled consolidation theory using finite elements. A dimensionless time factor is used to present the results of pore-pressure dissipation. These results are presented using nondimensional quantities and in normalized forms. The results are directly applicable to estimation of pore pressures for determining long-term stability of tunnels. Key words : clay, pore pressure, tunnels, uncoupled consolidation, finite elements, stress-strain.

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