• Anisotropic poroelasticity – Does it apply to shale? 

      Holt, Rune Martin; Bakk, Audun; Bauer, Andreas (Journal article; Peer reviewed, 2018)
      Shale plays an important role as cap rock above oil and gas reservoirs and above e.g. CO2 storage sites, as well as being source and reservoir rock in development of so-called unconventional reserves. Shale anisotropy needs ...
    • Effect of non-linear elasticity on stress paths in depleted reservoirs and their surroundings 

      Lozovyi, Serhii; Yan, Hong; Holt, Rune Martin; Bakk, Audun (Chapter, 2020)
      The prediction of stress and strain changes in and around reservoir using numerical simulators is often based on assumption of linear elasticity before reaching yield point. However, it is known that rocks are generally ...
    • Experimental Studies of Stress Dependence,Static vs Dynamic behaviour and Mechanical Anisotropies of Shale 

      Holt, Rune Martin; Bakk, Audun; Bauer, Andreas; Fjær, Erling; Stenebråten, Jørn (Chapter, 2014)
      Laboratory data from controlled rock mechanical tests with various shales have been used to understand and quantify stress effects on wave velocities of relevance for 4D seismics, and to quantify the difference between ...
    • Offset dependence of overburden time-shifts from ultrasonic data 

      Bakk, Audun; Holt, Rune Martin; Bauer, Andreas; Dupuy, Bastien; Romdhane, Mohamed Anouar (Journal article; Peer reviewed, 2020)
      Depletion or injection into a reservoir implies stress changes and strains in the reservoir and its surroundings. This may lead to measurable time-shifts for seismic waves propagating in the subsurface. To better understand ...
    • Offset-Dependent Overburden Time-Shifts from Ultrasonic Data 

      Bakk, Audun; Holt, Rune Martin; Bauer, Andreas; Dupuy, Bastien; Romdhane, Mohamed Anouar (Chapter, 2019)
      Depletion or injection into a reservoir implies stress and strain changes in the reservoir and its surroundings. This may lead to measurable time-shifts for seismic waves propagating in the subsurface. We have measured ...
    • Overburden geomechanical effects on 4D seismic response - influences of stiffness contrast, anisotropy, and geometry 

      Li, Liming; Bauer, Andreas; Holt, Rune Martin; Fjær, Erling; Stenebråten, Jørn; Bakk, Audun (Journal article; Peer reviewed, 2014)
      Petroleum production and CO2 storage induce effective stress changes and deformations in the reservoir, as well as in the overburden. This may be detected by 4D seismic monitoring due to the stress-sensitivity of the seismic ...
    • Overburden pore-pressure changes and their influence on 4D seismic 

      Holt, Rune Martin; Bauer, Andreas Kurt Marcel; Bakk, Audun (Journal article; Peer reviewed, 2017)
      Changes in seismic two-way travel time in the overburden can be attributed to pore pressure changes in the underlying reservoir. Since cap rock permeability is very small, these stress changes occur without drainage on ...
    • Skempton's A – A key to man-induced subsurface pore pressure changes 

      Holt, Rune Martin; Bakk, Audun; Stenebråten, Jørn; Bauer, Andreas; Fjær, Erling (Chapter, 2018)
      Fluid production from or injection into a subsurface reservoir leads to stress pressure changes inside and outside the reservoir. The overburden often consists of low permeability shale, and the undrained pore pressure ...
    • SPE-174356-MS Effect of Rock Anisotropy on Integrated Modelling 

      Li, Liming; Bakk, Audun; Fjær, Erling; Bauer, Andreas; Stenebråten, Jørn; Holt, Rune Martin (Chapter, 2015)
      Associated with reservoir monitoring towards optimizing production of oil and gas and maximizing the recovery, or ensuring safe CO2 storage, it may be beneficial to introduce integrated geomechanics, rock physics and seismic ...
    • Static and Dynamic Characterization of a Deep Overburden Shale 

      Bakk, Audun; Stenebråten, Jørn; Lozovyi, Serhii; Bauer, Andreas; Sønstebø, Eyvind Frode; Fjær, Erling; Bhuiyan, Mohammad Hossain; Chakraborty, Samarjit; Holt, Rune Martin (Chapter, 2018)
      Since shales are the far most abundant overburden formation, understanding the geomechanical and rock physics behavior of shales is essential. We discuss a particular deep overburden shale in light of a thorough static and ...
    • Statistical Thermodynamics of Proteins 

      Bakk, Audun (Dr. ingeniøravhandling, 0809-103X; 2002:26, Doctoral thesis, 2002)
      The subject of this thesis is to formulate effective energy expressions (Hamiltonians) of proteins and protein related systems. By use of equilibrium statistical mechanics we calculate thermodynamical functions, whereupon ...
    • Stress Path Dependent Velocities in Shales: Impact on 4D Seismic Interpretation 

      Holt, Rune Martin; Bauer, Andreas; Bakk, Audun (Journal article; Peer reviewed, 2018)
      Overburden stresses and pore pressure are altered by depletion or inflation of a subsurface reservoir, leading to seismic travel time and reflectivity changes that may be interpreted as footprints of reservoir drainage or ...
    • Stress paths and predicted time-shifts around a depleting reservoir 

      Yan, Hong; Bakk, Audun; Holt, Rune Martin; Lozovyi, Serhii (Chapter, 2020)
      Time-lapse (4D) seismic is an essential tool for monitoring the subsurface in and around producing hydrocarbon or CO2 storage reservoirs. The seismic time-shifts, in the reservoir as well as in the overburden, depend on ...
    • Stress-path dependence of ultrasonic and seismi velocities in shale 

      Holt, Rune Martin; Bauer, Andreas Kurt Marcel; Bakk, Audun; Szewczyk, Dawid (Journal article, 2016)
      4D seismic time-shifts are induced by stress changes in the overburden as a result of depletion from or injection into an underlying reservoir. This represents a powerful technique for tracking unrecovered hydrocarbon ...
    • The Importance of Overburden Stress Path in Assessment of Stress Dependence for 4D Applications 

      Holt, Rune Martin; Bauer, Andreas Kurt Marcel; Bakk, Audun (Chapter, 2016)