Formation of detrital clay grain coats by dewatering of deep-water sands and significance for reservoir quality

2019 ◽  
Vol 89 (12) ◽  
pp. 1231-1249 ◽  
Author(s):  
Kristin W. Porten ◽  
Michał J. Warchoł ◽  
Ian A. Kane
Keyword(s):  
Pore Space ◽  
Pore Fluid ◽  
High Density ◽  
Seafloor Topography ◽  
Abrupt Decrease ◽  
Norwegian Sea ◽  
Seabed Topography ◽  
Gravity Flows ◽  
Rapid Deceleration ◽  
Hybrid Event

ABSTRACT Well-developed detrital clay grain coats are observed in deep-marine sandstones of the Upper Cretaceous Springar Formation of the Vøring Basin in the Norwegian Sea. The detrital clay coats form thin and compact rims on individual sand grains and meniscus-shaped bridges between grains. These well-developed coats are found in high-density turbidites and proximal hybrid event beds with common to pervasive dewatering structures deposited in proximity to the base of a syndepositionally active basin high. Here, in one exploration well, detrital clay grain coats are common throughout a sandstone package 100 m thick. High-density turbidites and proximal and distal hybrid event beds drilled in mid- to distal-fan settings unaffected by seismically resolved seafloor topography show common dewatering features, but have only scattered detrital clay coats confined to individual dewatering pipes or dish structures. Hence, we propose that intense sediment dewatering has the potential to form detrital clay coats in deep-marine sandstones by a combination of elutriation and reorganization of clays during fluid escape from sediment bodies with pore fluid pressures significantly higher than the hydrostatic pressure. In submarine fan systems, deposition of sediment with coeval trapping of large volumes of interstitial pore fluid is most likely to occur where gravity flows undergo rapid deceleration in response to an abrupt decrease in confinement or gradient. Such environments include the channel–lobe transition and settings in proximity to seabed topography. The investigated sandstones are quartz arenites and subarkoses, with minor to moderate volumes of quartz cement (up to 6%). However, strongly to completely quartz-cemented intergranular pore space is observed where detrital clay coats or matrix does not cover quartz grains in the deepest part of the studied formation. Modeling of quartz cementation predicts that most intergranular macroporosity in the lower part of the Springar Formation would be quartz cemented if the sandstones were free of detrital clays. Based on our observations and modeling results we propose that intense sediment dewatering has the potential to form detrital clay coats, which can be important for retaining porosity in deeply buried sandstones and in basins with high present or past heat flow.

A dynamic elastic model for squirt-flow effect and its application on fluid-viscosity-associated velocity dispersion in reservoir sandstones

Geophysics ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. MR201-MR212
Author(s):  
Zhi-Qiang Yang ◽  
Tao He ◽  
Chang-Chun Zou
Keyword(s):  
Velocity Dispersion ◽  
Pore Space ◽  
Pore Fluid ◽  
Quantitative Prediction ◽  
Elastic Model ◽  
Fluid Viscosity ◽  
Porous Rocks ◽  
S Wave ◽  
Flow Effect ◽  
Reservoir Sandstones

Velocity dispersion is a common phenomenon for fluid-charged porous rocks and carries important information on the pore structure and fluid in reservoir rocks. Previous ultrasonic experiments had measured more significant non-Biot velocity dispersion on saturated reservoir sandstones with increasing pore-fluid viscosity. Although wave-induced local squirt-flow effect could in theory cause most of the non-Biot velocity dispersion, its quantitative prediction remains a challenge. Several popular models were tested to predict the measured velocities under undrained conditions, but they either underestimated the squirt-flow effect or failed to simultaneously satisfy P- and S-wave velocity dispersions (especially for higher viscosity fluids). Based on the classic double-porosity theory that pore space is comprised of mainly stiff/Biot’s porosity and minor compliant porosity, an effective “wet frame” was hypothesized to account for the squirt-flow effect, whose compliant pores are filled with a hypothesized fluid with dynamic modulus. A new dynamic elastic model was then introduced by extending Biot theory to include the squirt-flow effect, after replacing the dry-frame bulk/shear moduli with their wet-frame counterparts. In addition to yielding better velocity predictions for P- and S-wave measurements of different fluid viscosities, the new model is also more applicable because its two key tuning parameters (i.e., the effective aspect ratio and porosity of compliant pores) at in situ reservoir pressure could be constrained with laboratory velocity measurements associated with pore-fluid viscosities.

scholarly journals Hybrid event beds dominated by transitional-flow facies: character, distribution and significance in the Maastrichtian Springar Formation, north-west Vøring Basin, Norwegian Sea

Sedimentology ◽  
2017 ◽  
Vol 64 (3) ◽  
pp. 747-776 ◽  
Author(s):  
Sarah J. Southern ◽  
Ian A. Kane ◽  
Michał J. Warchoł ◽  
Kristin W. Porten ◽  
William D. McCaffrey
Keyword(s):  
Transitional Flow ◽  
Norwegian Sea ◽  
North West ◽  
Character Distribution ◽  
Vøring Basin ◽  
Hybrid Event

scholarly journals Influence of pH liquid for mixing gypsum binders on the strength of gypsum composites

2020 ◽  
Vol 315 ◽  
pp. 10001
Author(s):  
Victoria Petropavlovskaya ◽  
Maria Zavadko ◽  
Tatiana Novichenkova
Keyword(s):  
Chemical Composition ◽  
Structure Formation ◽  
Pore Fluid ◽  
High Density ◽  
Material Composition ◽  
Natural Minerals ◽  
Influence Of Ph ◽  
Properties Of Composites

The influence of fluid acidity on the processes of hardness, mechanism, kinetics, properties of gypsum stone are of great interest.Studies of these processes for modified composites based on gypsum and heavy high density and basalt additives can improve the modifier's effectiveness. The influence of the pH of a liquid on the processes of structure formation and the properties of composites is determined in this work. It is shown that the pH should be shared by other structure-forming factors. This is the chemical composition of basalt waste, its percentage, the interaction of its oxides with pore fluid and natural minerals are the products of their reaction. The regulation of the material composition of composites can enhance the properties and also lead to degradation of structures.

Facies and provenance of deep marine sediment gravity flows with fragments of coalified land plants at Lipowica, the Cergowa Beds (Oligocene), Outer Carpathians of Poland

2021 ◽  
Author(s):  
Joanna Pszonka ◽  
Marek Wendorff ◽  
Magdalena Zielińska ◽  
Paweł Godlewski
Keyword(s):  
Organic Matter ◽  
High Density ◽  
Turbidity Currents ◽  
Terrestrial Plants ◽  
Terrestrial Organic Matter ◽  
Fine Grained ◽  
Lower Stage ◽  
Gravity Flows ◽  
Facies Associations ◽  
Outer Carpathians

<p>Facies analysis of the Cergowa Beds of the Polish and Slovak Outer Carpathians shows that this deep-marine siliciclastic unit was deposited by a spectrum of gravity flows ranging from high to low density, which deposited three facies associations (A, B and C). Association A consists of very fine- to medium-grained sandstones with mudstone and coal clasts, granules and rich in coalified organic matter fragments. Sandstones beds reach 8 m in thickness, are massive and subordinately parallel laminated (Ta and Tab). They are interpreted as resulting from incremental, rapid deposition from collapse of a near-bed layer (Ta, Tab) and laterally sheared near-bed layer (Tb) below high-density, turbulent flows and steady turbidity currents or, in case of mud-rich sandstones, en masse deposition by debris flows. Association B comprises very fine- and fine-grained sandstones with mud and coal clasts, granules and coalified plant fragments and detritus. They are massive, parallel- and ripple cross-laminated (Tab, Tabc, Tbc), reach 2 m in thickness and contain mudstone intercalations up to 50 cm. These sandstones seem to have originated from a combination of incremental deposition by high-density turbidity currents (Tab, Tb), low-amplitude bedload waves at the upper stage planar lamination in more dilute turbidity current (Tb) and suspension of fully turbulent and dilute turbidity currents (Tbc, Tc). Association C consists of very fine- to fine-grained sandstones and siltstones with fine organic detritus and minor mud clasts. Parallel- and ripple cross-lamination (Tbc, Tbcd) dominate, bed thickness of sandstones and siltstones amounts to 1-50 cm and mudstones reaches 200 cm. Association C was deposited by transformation of waning, dilute and fully turbulent turbidity currents from ripples into lower stage planar lamination.</p><p>Sandstone and mudstone beds at Lipowica (Poland) contain three types of coalified terrestrial organic matter. Based on their morphology and size these are: (i) coalified plant detritus dispersed in B and C associations, (ii) coalified plant fragments forming elongated lenses in A and B associations and (iii) coalified fragments of tree trunks occurring in A and B facies. Petrographic components of organic matter represented by collotelinite, telinite, gelinite and fusinite with co-occuring framboidal pyrite indicate terrestrial plants affected by fast gelification and burial processes of varying intensity. The size of the plant fragments supplied to the Dukla basin is positively correlated with indicators of hydrodynamic regimes suggested by their hosting sediments. Namely, the larger the fragments, the higher flow energy and steadier and longer lasting sustained sediment delivery.</p><p>Sedimentary features of the Cergowa Beds suggest deposition out of gradually aggrading sustained turbulent sandy gravity flows primarily controlled by hyperpycnal effluents from a delta. Palaeocurrent data and comparison of mineral composition of sandstone infilling a hollow coalified tree trunk at Lipowica quarry with sandstone beds of the hosting succession suggest provenance from shelf fringing the emergent Silesian Ridge, which acted as a source area to the west of the basin. The depositional age NP23 and NP24 during the Oligocene eustatic sea-level fall implies that the delta supplying the Cergowa basin was located at the edge of this shelf.</p>

Seismic pore space compressibility and Gassmann’s relation

Geophysics ◽  
1995 ◽  
Vol 60 (6) ◽  
pp. 1743-1749 ◽  
Author(s):  
Gary Mavko ◽  
Tapan Mukerji
Keyword(s):  
Bulk Modulus ◽  
Pore Space ◽  
Pore Fluid ◽  
Fluid Substitution ◽  
Effective Moduli ◽  
Pore Compressibility ◽  
Robust Model ◽  
Gassmann’S Equation ◽  
Model Independent

The pore space compressibility of a rock provides a robust, model‐independent descriptor of porosity and pore fluid effects on effective moduli. The pore space compressibility is also the direct physical link between the dry and fluid‐saturated moduli, and is therefore the basis of Gassmann’s equation for fluid substitution. For a fixed porosity, an increase in pore space compressibility increases the sensitivity of the modulus to fluid substitution. Two simple techniques, based on pore compressibility, are presented for graphically applying Gassmann’s relation for fluid substitution. In the first method, the pore compressibility is simply reweighted with a factor that depends only on the ratio of fluid to mineral bulk modulus. In the second technique, the rock moduli are rescaled using the Reuss average, which again depends only on the fluid and mineral moduli.

Numerical Modeling of Pore Fluid Flow in Reconstructed Porous Media

2015 ◽  
Author(s):  
Zhenyu Liu ◽  
Huiying Wu
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Fluid Flow ◽  
Two Phase Flow ◽  
Pore Space ◽  
Pore Fluid ◽  
Phase Flow ◽  
Computational Domain ◽  
Two Phase ◽  
Reconstructed Porous Media

In this paper, the numerical simulation of pore fluid flow in reconstructed porous media was carried out. The 3D porous computational domain was reconstructed based on the 2D images from micro CT scanner equipment. The Shan-Chen type lattice Boltzmann method (LBM) was adopted to establish the numerical model to predict the two-phase flow in the complex porous domain. The pore space is in micro/mini scale and the surface structure will have an influence on the pore fluid flow. Different surface tension coefficients were adopted in the numerical simulation to analyze its effect on the two-phase flow in complex porous media.

scholarly journals Dynamic permeability functions for partially saturated porous media

2020 ◽  
Vol 221 (2) ◽  
pp. 1182-1189
Author(s):  
Santiago G Solazzi ◽  
J Germán Rubino ◽  
Damien Jougnot ◽  
Klaus Holliger
Keyword(s):  
Porous Media ◽  
Effective Permeability ◽  
Pore Space ◽  
Pore Fluid ◽  
Immiscible Fluid ◽  
Saturated Porous Media ◽  
Partially Saturated ◽  
Dynamic Permeability ◽  
Partially Saturated Porous Media ◽  
Fluid Phases

SUMMARY While the frequency-dependence of permeability under fully saturated conditions has been studied for decades, the corresponding characteristics of partially saturated porous media remain unexplored. Notably, it is not clear whether the use of effective pore fluid approaches under such conditions is valid. To address this issue, we propose a method that allows us to obtain dynamic permeability functions for partially saturated porous media. To this end, we conceptualize the considered pore space as a bundle of capillary tubes of different radii saturated by two immiscible fluid phases. We then solve the Navier–Stokes equations within the pore space and define a capillary pressure–saturation relationship, which permits to obtain saturation- and frequency-dependent effective permeability estimates. The application of this method to a realistic model of an unconsolidated granular sediment demonstrates that dynamic effective permeability functions for wetting and non-wetting fluid phases exhibit distinct characteristics, thus rendering effective pore fluid approaches inadequate. Finally, we explore the capability of the seminal dynamic permeability model developed by Johnson et al.[J. Fluid Mech. 176, 379 (1987)] to account for the effects of partial saturation. We find that the frequency scaling proposed by Johnson et al. prevails in partially saturated scenarios. However, the parameters associated with this model need to be redefined to account for saturation-dependent effects.

scholarly journals The Numerical study of the influence of a two-scale pore structure on the dynamic strength of water-saturated concrete

2020 ◽  
pp. 37-51
Author(s):  
Ig. S Konovalenko ◽  
E. V Shilko ◽  
Iv. S Konovalenko
Keyword(s):  
Pore Structure ◽  
Master Curve ◽  
Pore Space ◽  
Dynamic Strength ◽  
Pore Fluid ◽  
Surface Layers ◽  
Saturated Concrete ◽  
Water Saturated ◽  
Mechanical Influence ◽  
Capillary Pore

Many infrastructural concrete facilities, such as dams, bridge footings, foundations of port facilities and offshore drilling platforms, operate in a permanent contact with water. The permeable fractured-porous structure of concrete determines the water-saturated state of the surface layers of such concrete elements. Under dynamic contact loading, the pore fluid is capable of exerting a significant mechanical influence on the local stress-strain state and strength characteristics of the surface layers of concrete. This has to be taken into account when assessing the wear intensity of surface layers and predicting a concrete element’s service life. The aforesaid determines the relevance of the study aimed at identifying the influence of the pore fluid and characteristics of the concrete pore structure on the strength and fracture pattern under quasistatic and dynamic compressive loading. The present work is devoted to the theoretical study and generalization of the laws of mechanical influence of the pore fluid on the dynamic strength of high-strength concrete with a two-scale pore structure. The emphasis in the study is on analyzing the contributions of each of the pore subsystems to the integral mechanical effect of the fluid. To carry out such an analysis, a coupled hydromechanical model is developed. It takes into account the compositional structure of concrete, the presence of a pore space in a cement stone of two different scales, the interaction of a pore liquid and a solid-phase skeleton based on the Bio poroelasticity model, as well as fluid filtration in a pore space. By using the developed model were performed the numerical studies of the dependence between the compressive strength of the representative concrete volumes of the mesoscopic scale on the strain rate, the sample size, the pore fluid viscosity, and pore structure parameters. The simulation results showed the possibility of combining the obtained dependencies into a generalized (master) curve in terms of a combined dimensionless parameter, which has the meaning similar to the Darcy number. We identified two key factors that control the type and parameters of the concrete master curve of the dynamic strength. The first factor is the mobility of the pore fluid in the network of the capillary pores. It determines the rate of stress equalization in the porous skeleton due to fluid flow. The second factor is the interconnection of large micropores with the network of the small capillary pore channels. It determines the magnitude of the decrease in stress concentration in micropores by filtering the excess pore fluid into the capillary pore network. It is shown that the contributions of these two factors to the amplitude of variation of the dynamic strength of the water-saturated concrete are additive, and their total contribution reaches 25 %.

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