... ABSTRACT: The present study is part of the Bifrost project and aims at assessing the feasibility of storing CO 2 in chalk reservoirs by using the depleted Harald East gas field located in the northern part of the Danish North Sea as a showcase. Chalk is a singular rock with a high...

... facilitates this phenomenon (Papamichos et al. 1993). High porosity chalks on the other hand experience pore collapse where the open skeleton structure of the material breaks, and destructures giving a sharp decline in porosity (e.g., Papamichos et al. 1997). Both phenomena cause fundamental changes...

... is carried out in the Harald East chalk field to assess the flow and mechanical response of the storage site, assuming both continuous and intermittent injection. A total of two continuous injection scenarios during 16 years (scenario 1) and 32 years (scenario 2) and scenario 3 which assumes intermittent...

...-plastic material in heterogeneous chalk reservoirs for compaction analysis which are optimized from history matching the surface subsidence. To this purpose, a 2D simulation case with over-burden, reservoir and under-burden is considered as a conceptual model. A random distribution of porosity field...

... ABSTRACT: The experimental studies highlighting the strength weakening of chalk when water replaces oil in pore space have incited geomodellers to systematically solve for the effect of water saturation on chalk strength at each simulation step to estimate reservoir compaction. The present...

... ABSTRACT: Despite the overall consistency of chalk in terms of reservoir properties across Danish North Sea fields, most of the constitutive models were successfully applied to one single hydrocarbon field. This study aims at building a comprehensive geomechanical model capable of predicting...

... data from the field. Introduction As pressure changes during the production of hydrocarbon from reservoirs, chalk may compact due to change in in situ stresses and saturating fluids. Subsurface deformation is transferred to the sideburden, overburden and earth surface, resulting into wellbore...

... ABSTRACT: Experimental evidence has shown that water-saturated chalk specimens are weaker than oil-saturated samples. The extent of water-induced weakening does not rely only on the stress state and degree of saturation but also on temperature, brine composition, and mineralogy. Our goal...

... of relatively high-porosity (20-45%) chalks, marls, and oil shales with kerogen. This paper describes preliminary measurements, analyses of thermal hydrological mechanical (THM) properties and expected borehole stability for a potential high level nuclear waste borehole repository in Israel. This effort is part...

... ABSTRACT: Acidizing and wormholing in carbonate reservoirs is studied through the analysis of the linear acidizing problem theoretically and experimentally. Experimentally, linear acidizing tests were performed in Mons chalk, a high porosity analogue of North Sea reservoir chalk...

... ABSTRACT: Multi-scale numerical geomechanical models for reservoir and overburden deformation in the Tyra chalk field (Denmark) were made, and calibrated by laboratory deformation tests and field data. The mechanical interaction between the compacting and deforming formation, cement...

... Abstract: We investigated the rock physics of immature organic-rich chalk from the Late Cretaceous Ghareb and Mishash formations in the Shefela basin, central Israel, and its variation upon pyrolysis-induced maturation. The study was carried out on core samples from a ~280 meters sequence...

... subsidence are in much better agreement. The additional and accelerating subsidence above the Harlingen gas field can only be explained by pore-collapse of the gas-bearing reservoir chalk. During the laboratory compaction tests used for the original subsidence predictions, pore collapse only occurred...

... process by carrying out a numerical creep analysis of the failure mechanisms. This is performed based using a coupled constitutive law developed to account for the long term degradation phenomenon of the chalk continuum in the presence of joints. Numerical analysis of the time dependant behavior...

... Abstract The rate dependence of dry, oil- or water-saturated high-porosity outcrop chalk is investigated based on whether the fluid effect could be excluded from a governing material parameter, the b-factor. The b-factor is used in geotechnical engineering to establish the difference...

... experiments have been performed on hollow cylinder cores of different rocks - sandstones and chalks. Our analyses show that the amplitudes and energies of acoustic events clearly indicate initiation and propagation of the main fractures. The amplitudes of AE events follow an exponential distribution while...

... Abstract One way to stimulate oil production from chalk reservoirs is to inject acid into the formation which results in the formation of wormholes that act as flow channels. The aim of this study was to investigate the mechanical stability of wormholes in chalk and the impact...

... Abstract: The strength of high porosity, low permeability, and weakly cemented chalk is highly dependent on the type of saturating fluid. This paper proposes that a key factor in the mechanism behind fluid-induced weakening of chalk is the compressibility of the fluid in the friction...

... Abstract: The objective of the study is to investigate how the presence of sulfate in pore water not only affects the mechanical behavior of chalk, but, also how it affects wettability change and the capillary pressure curve. We present the spontaneous imbibition capillary pressure curves...

... of the effective stress itself remain unknown without the use of tailored experimental techniques. Here, we present the results from four independent testing methods for estimating the Biot stress coefficient of high porosity chalk. We discuss the microscopic interpretation of the Biot coefficient and show how...