Effect of Confinement on Pressure/Volume/Temperature Properties of Hydrocarbons in Shale Reservoirs

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 621-634 ◽  
Author(s):  
T.. Pitakbunkate ◽  
P. B. Balbuena ◽  
G. J. Moridis ◽  
T. A. Blasingame
Keyword(s):  
Phase Behavior ◽  
Phase Diagrams ◽  
Energy Resource ◽  
The United States ◽  
Confined Space ◽  
Bulk Fluid ◽  
Mixture Phase ◽  
Fluid Properties ◽  
Shale Reservoirs ◽  
Gcmc Simulations

Summary Shale reservoirs play an important role as a future energy resource of the United States. Numerous studies were performed to describe the storage and transport of hydrocarbons through ultrasmall pores in the shale reservoirs. Most of these studies were developed by modifying techniques used for conventional reservoirs. The common pore-size distribution of the shale reservoirs is approximately 1 to 20  nm and in such confined spaces that the interactions between the wall of the container (i.e., the shale and kerogen) and the contained fluids (i.e., the hydrocarbon fluids and water) may exert significant influence on the localized phase behavior. We believe this is because the orientation and distribution of fluid molecules in the confined space are different from those of the bulk fluid, causing changes in the localized thermodynamic properties. This study provides a detailed account of the changes of pressure/volume/temperature properties and phase behavior (specifically, the phase diagrams) in a synthetic shale reservoir for pure hydrocarbons (methane and ethane) and a simple methane/ethane (binary) mixture. Grand canonical Monte Carlo (GCMC) simulations are performed to study the effect of confinement on the fluid properties. A graphite slab made of two layers is used to represent kerogen in the shale reservoirs. The separation between the two layers, representing a kerogen pore, is varied from 1 to 10  nm to observe the changes of the hydrocarbon-fluid properties. In this paper, the critical properties of methane and ethane as well as the methane/ethane mixture phase diagrams in different pore sizes are derived from the GCMC simulations. In addition, the GCMC simulations are used to investigate the deviations of the fluid densities in the confined space from those of the bulk fluids at reservoir conditions. Although not investigated in this work, such deviations may indicate that significant errors for production forecasting and reserves estimation in shale reservoirs may occur if the (typical) bulk densities are used in reservoir-engineering calculations.

Numerical Investigation of Gravitational Compositional Grading in Hydrocarbon Reservoirs Using Centrifuge Data

2009 ◽  
Vol 12 (05) ◽  
pp. 793-802 ◽  
Author(s):  
P. David Ting ◽  
Birol Dindoruk ◽  
John Ratulowski
Keyword(s):  
Experimental Data ◽  
Phase Behavior ◽  
Rock Properties ◽  
Model Parameters ◽  
Fluid Composition ◽  
Bulk Fluid ◽  
Reservoir Fluid ◽  
Fluid Systems ◽  
Fluid Properties ◽  
The Impact

Summary Fluid properties descriptions are required for the design and implementation of petroleum production processes. Increasing numbers of deep water and subsea production systems and high-temperature/high-pressure (HTHP) reservoir fluids have elevated the importance of fluid properties in which well-count and initial rate estimates are quite crucial for development decisions. Similar to rock properties, fluid properties can vary significantly both aerially and vertically even within well-connected reservoirs. In this paper, we have studied the effects of gravitational fluid segregation using experimental data available for five live-oil and condensate systems (at pressures between 6,000 and 9,000 psi and temperatures from 68 to 200°F) considering the impact of fluid composition and phase behavior. Under isothermal conditions and in the absence of recharge, gravitational segregation will dominate. However, gravitational effects are not always significant for practical purposes. Since the predictive modeling of gravitational grading is sensitive to characterization methodology (i.e., how component properties are assigned and adjusted to match the available data and component grouping) for some reservoir-fluid systems, experimental data from a specially designed centrifuge system and analysis of such data are essential for calibration and quantification of these forces. Generally, we expect a higher degree of gravitational grading for volatile and/or near-saturated reservoir-fluid systems. Numerical studies were performed using a calibrated equation-of-state (EOS) description on the basis of fluid samples taken at selected points from each reservoir. Comparisons of measured data and calibrated model show that the EOS model qualitatively and, in many cases, quantitatively described the observed equilibrium fluid grading behavior of the fluids tested. First, equipment was calibrated using synthetic fluid systems as shown in Ratulowski et al. (2003). Then real reservoir fluids were used ranging from black oils to condensates [properties ranging from 27°API and 1,000 scf/stb gas/oil ratio (GOR) to 57°API and 27,000 scf/stb GOR]. Diagnostic plots on the basis of bulk fluid properties for reservoir fluid equilibrium grading tendencies have been constructed on the basis of interpreted results, and sensitivities to model parameters estimated. The use of centrifuge data was investigated as an additional fluid characterization tool (in addition to composition and bulk phase behavior properties) to construct more realistic reservoir fluid models for graded reservoirs (or reservoirs with high grading potential) have also been investigated.

Confinement Effects on Phase Behavior of Hydrocarbon in Nanochannels

2015 ◽  
Author(s):  
M. Alfi ◽  
H. Nasrabadi ◽  
D. Banerjee
Keyword(s):  
Phase Behavior ◽  
Bubble Nucleation ◽  
Well Performance ◽  
Pvt Properties ◽  
Bubble Point Pressure ◽  
Numerical Predictions ◽  
Fluid Properties ◽  
Different Temperatures ◽  
Point Pressure ◽  
Shale Reservoirs

Several researchers have recently studied the phase behavior of petroleum fluids in shale systems. There is a general agreement that the confined PVT properties in shale are substantially different from the corresponding bulk properties. These differences have significant impact on the prediction of well performance and ultimate recovery in shale reservoirs. Experimental measurements of fluid properties in shale rocks are currently not available. This has led to significant amount of uncertainty in phase behavior calculations for shale reservoirs. In this study, experimental validation of numerical predictions for phase behavior of various hydrocarbons confined in nanochannels was performed using a nanofluidics platform. The nanofluidics platform was designed, fabricated and tested at different temperatures. Design of the nanochannel is described in this paper. In this study, a nanochannel device (similar to Duan and Majumdar 2010) was designed, fabricated, packaged and tested. The reservoirs in the nanofluidic chip were filled with various hydrocarbon liquids (e.g. n-decane). The temperature was varied at a constant pressure, during which epifluorescence imaging was performed to measure the bubble nucleation temperature, i.e., the temperature corresponding to the formation of the first bubble of gas (i.e., to determine bubble-point pressure and temperature relationship).

Nearshore wave energy resource characterization along the East Coast of the United States

2021 ◽  
Vol 172 ◽  
pp. 1212-1224
Author(s):  
Seongho Ahn ◽  
Vincent S. Neary ◽  
Mohammad Nabi Allahdadi ◽  
Ruoying He
Keyword(s):  
United States ◽  
Wave Energy ◽  
East Coast ◽  
Energy Resource ◽  
The United States

A simulation study of self-assembly of ABC star terpolymers confined between two parallel surfaces

Soft Matter ◽  
2021 ◽  
Author(s):  
Zhiyao Liu ◽  
Zheng Wang ◽  
Yuhua Yin ◽  
Run Jiang ◽  
Baohui Li
Keyword(s):  
Simulated Annealing ◽  
Phase Behavior ◽  
Phase Diagrams ◽  
Simulation Study ◽  
Self Assembly ◽  
Simulated Annealing Method ◽  
Parallel Surfaces ◽  
Annealing Method

Phase behavior of ABC star terpolymers confined between two identical parallel surfaces is systematically studied with a simulated annealing method. Several phase diagrams are constructed for systems with different bulk...

Phase Relationship Studies of Silicon Nitride System—A Key to Materials Design

1992 ◽  
Vol 287 ◽  
Author(s):  
T.S. Yen ◽  
W.Y. Sun
Keyword(s):  
Elevated Temperature ◽  
Silicon Nitride ◽  
Grain Boundary ◽  
Phase Behavior ◽  
Phase Diagrams ◽  
Room Temperature ◽  
Phase Relationship ◽  
Materials Design ◽  
Basic Approach ◽  
System A

ABSTRACTAdditions and revisions to several of the most important phase diagrams and phase behavior diagrams in the silicon nitride field are reviewed in this work, with emphasis on the Y-Si-A1-O-N system. This information is further used to make observations on the promising silicon nitride systems containing either highly refractory grain boundary phases or compatible matrix phases of desirable properties. Examples are provided to illustrate the advantage of such a basic approach to materials design. Hardness, toughness, strength at room temperature and elevated temperature and even sinterability can all be improved by adopting such an approach.

scholarly journals The Seepage Model Considering Liquid/Solid Interaction in Confined Nanoscale Pores

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Xiaona Cui ◽  
Erlong Yang ◽  
Kaoping Song ◽  
Yuming Wang
Keyword(s):  
Solid Wall ◽  
Pore Wall ◽  
Interaction Coefficient ◽  
Two Dimensions ◽  
Navier Stokes ◽  
Confined Space ◽  
Navier Stokes Equation ◽  
Capillary Radius ◽  
Seepage Model ◽  
Shale Reservoirs

Different from conventional reservoirs, nanoscale pores and fractures are dominant in tight or shale reservoirs. The flow behaviors of hydrocarbons in nanopores (called “confined space”) are more complex than that of bulk spaces. The interaction between liquid hydrocarbons and solid pore wall cannot be neglected. The viscosity formula which is varied with the pore diameter and interaction coefficient of liquids and solids in confined nanopores has been introduced in this paper to describe the interaction effects of hydrocarbons and pore walls. Based on the Navier-Stokes equation, the governing equation considered liquid/solid effect in two dimensions has been established, and approximate theoretical solutions to the governing equations have been achieved after mathematic simplification. By introducing the vortex equation, the complex numerical seepage model has been discretized and solved. Numerical results show that the radial velocity distribution near the solid wall has an obvious change when considering the liquid/solid interaction. The results consist well with that approximate mathematical solution. And when the capillary radius is smaller, the liquid and solid interaction coefficient n is greater. The liquid and solid interaction obviously cannot be neglected in the seepage model if the capillary radius is small than 50 nm when n>0.1. The numerical model has also been further validated by two types of nanopore flow tests: from pore to throat and inversely from throat to pore. There is no big difference in flow regularity of throat to pore model considering when liquid/solid interaction or not, whereas the liquid/solid interaction of pore to throat model totally cannot be overlooked.

scholarly journals Kinetic bottlenecks to chemical exchange rates for deep-sea animals II: Carbon dioxide

2012 ◽  
Vol 9 (11) ◽  
pp. 15787-15821 ◽  
Author(s):  
A. F. Hofmann ◽  
E. T. Peltzer ◽  
P. G. Brewer
Keyword(s):  
Boundary Layer ◽  
Gas Exchange ◽  
Chemical Exchange ◽  
Co2 Concentration ◽  
Base System ◽  
Co2 Efflux ◽  
Marine Animals ◽  
Bulk Fluid ◽  
Marine Life ◽  
Fluid Properties

Abstract. Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑CO2] etc.) as the critical variable and with a major focus on carbonate shell dissolution. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyze the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T) and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas since, as with gas exchange of CO2 at the air-sea interface, the influence of the ensemble of reactions within the CO2-HCO3–-CO32– acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and flow rate under typical oceanic concentrations.The effect of these reactions can be described by an enhancement factor. For organisms, this means mechanically increasing flow over their surface to thin the boundary layer as is required to alleviate O2 stress seems not necessary to facilitate CO2 efflux. Nevertheless the elevated pCO2 cost most likely is non-zero. Regionally as with O2 the combination of T, P, and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth. But the net result is that, for the problem of gas exchange with the bulk ocean, the combination of an increasing T combined with declining O2 poses a greater challenge to marine life than does increasing CO2. The relationships developed here allow a more accurate prediction of the impacts on marine life from the combined effects of changing T, O2, and CO2 than can be estimated from single variable studies.

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