... elastic anisotropy anisotropic poroelasticity poroelasticity effect young poisson ARMA 22 0694 Effects of anisotropic poroelasticity on stress and pore pressure changes around subsurface reservoirs and storage sites Holt, R.M. NTNU Geoscience & Petroleum, Trondheim, Norway Bakk, A. SINTEF Industry...

... Summary Estimating subsurface stress or pore pressure from seismic velocities typically relies on specific petrophysical relationships. Most of the commonly used velocity-stress equations are designed for isotropic media and describe single (P- or S-wave) velocity versus confining stress...

.... Wellbore stability and fault stability models have been constructed using both a well-centric approach and a full field-wide 3D numerical solution. It is clearly observed that field-based approach provided us more accurate estimation of overburden stresses, variation of pore pressure across the field...

... ABSTRACT Accurate constraint of subsurface pore pressure is a critical component of safe drilling programmes. This is particularly challenging for exploratory wells where information on subsurface geology and the stress/pore pressure regime is often limited to seismic inversion. Drilling near...

.../fractures etc. Geomechanical model of the subsurface is represented as Mechanical Earth Model (MEM). It is a depth-wise representation of rock properties which as a minimum include – rock's elastic property, geo-stresses, pore pressure, stress azimuth along with other aspects referenced to a stratigraphic...

... ABSTRACT: 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 response may be estimated from Skempton’s empirical equations...

... Stress theorem should be applied to. The novelty of dividing the subsurface into four zones using this new approach reduces the risk of predicting the pore pressure before drilling and the uncertainty of its correct calibration during drilling. This new pore pressure calculation is done separately...

... ABSTRACT Understanding the pore pressures and stress distribution within the subsurface is of paramount importance in the design of a well in order to accurately determine the allowable drilling window. Many of the conventional methods that exist to predict the pore pressures and stresses...

... rainfall. Injection increases pore pressure in the reservoir, which expands volumetrically and affects surrounding elastic stresses. Models which seek to quantify this change are often poorly constrained, and so spatially-constrained measurements of the subsurface response would represent excellent...

... plate (figure 1), and ii) a pore throat model with an oil droplet (figure 2). We calculate stress changes at the fracture wall induced by unsteady flow for i) and multi-phase flow for ii). The unsteady flow is generated by cyclic pressure change at the inflow boundary. In this case, inner portion...

... Abstract Nearby field production effects in field development is a key consideration in well design for safe well delivery and HSE considerations. Formation Pore Pressure Prediction (PPP) aims to identify and manage formation pressures with associated subsurface uncertainties/risks, and serves...

... in-situ during hydraulic fracturing process, a necessary condition for their formation is that the minimum principal Terzaghi effective stress is negative (compressive stresses are positive throughout the paper): < 0, (1) where p is the pore pressure and is the minimum principal stress...

..., without establishing the geological groundwork for these mathematical equations, results can be misleading. The subsurface pore pressure build up partitions are mainly caused by compaction stress and compartmentalized lithology in an aqueous environment. Stress, fluid expansion and the presence of top...

... inverted acoustic impedance into velocity and density. Although pore-pressure measurements are typically low resolution, impedance inversion helps identify subsurface lithofacies, so that appropriate rock models can be built for effective stress and density functions. However, transformation of acoustic...

..., interpretations of surfaces and faults, etc.), propagation of properties and evaluation of results. All available data were collected which included the seismic horizons and faults, mechanical properties and stresses from 1-D MEMs and reservoir geometries and pore pressures. Multiple 1D MEMs were constructed...

..., stress conditions in the subsurface, and the pore pressure. Analyzing the geomechanical situation and incorporating them into the fine plan to design parameters that provides an economically viable solution for better reservoir-stress characterization and predicts its mechanical response through...

... through time. To perform the proper numerical geomechanics study, it requires the detailed input to characterize the reservoir and surrounded subsurface geology. Moreover, the understanding of how stresses acting on the reservoir in static and dynamic condition is crucial. When the pore pressure...

..., the work in Ref 4 is expanded to present relationships of minimum horizontal stress versus depth within the subsurface. Two approaches are employed – one where the pore pressure is known or can be estimated with good certainty, and another where pore pressure is not known. An additional improvement...

... the safe and efficient drilling of wells. These ISD products include an ‘ever-green’ geological model of the field, with overburden, reservoir and aquifer descriptions, plus 3D models of stress and pore-pressure. Such is the complexity of the pore pressure story at Shah Deniz that this represents one...