scholarly journals Poromechanical controls on spontaneous imbibition in earth materials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amir H. Haghi ◽  
Richard Chalaturnyk ◽  
Martin J. Blunt ◽  
Kevin Hodder ◽  
Sebastian Geiger
Keyword(s):  
Multiphase Flow ◽  
Effective Stress ◽  
Fluid Transport ◽  
Water Saturation ◽  
Pore Space ◽  
Analytical Calculation ◽  
Spontaneous Imbibition ◽  
Fundamental Study ◽  
Irreducible Water Saturation ◽  
The Impact

AbstractOver the last century, the state of stress in the earth’s upper crust has undergone rapid changes because of human activities associated with fluid withdrawal and injection in subsurface formations. The stress dependency of multiphase flow mechanisms in earth materials is a substantial challenge to understand, quantify, and model for many applications in groundwater hydrology, applied geophysics, CO2 subsurface storage, and the wider geoenergy field (e.g., geothermal energy, hydrogen storage, hydrocarbon recovery). Here, we conduct core-scale experiments using N2/water phases to study primary drainage followed by spontaneous imbibition in a carbonate specimen under increasing isotropic effective stress and isothermal conditions. Using X-ray computed micro-tomography images of the unconfined specimen, we introduce a novel coupling approach to reconstruct pore-deformation and simulate multiphase flow inside the deformed pore-space followed by a semi-analytical calculation of spontaneous imbibition. We show that the irreducible water saturation increases while the normalized volume of spontaneously imbibed water into the specimen decreases (46–25%) in response to an increase in effective stress (0–30 MPa), leading to higher residual gas saturations. Furthermore, the imbibition rate decreases with effective stress, which is also predicted by a numerical model, due to a decrease in water relative permeability as the pore-space becomes more confined and tortuous. This fundamental study provides new insights into the physics of multiphase fluid transport, CO2 storage capacity, and recovery of subsurface resources incorporating the impact of poromechanics.

Impact of water saturation on the elastic anisotropy of the Whitby Mudstone, United Kingdom

Geophysics ◽  
2020 ◽  
Vol 85 (1) ◽  
pp. MR57-MR72
Author(s):  
Lisanne A. N. R. Douma ◽  
Jeremie Dautriat ◽  
Joel Sarout ◽  
David N. Dewhurst ◽  
Auke Barnhoorn
Keyword(s):  
United Kingdom ◽  
Water Content ◽  
Effective Stress ◽  
Water Saturation ◽  
Elastic Anisotropy ◽  
Pore Space ◽  
Seismic Exploration ◽  
Complex Nature ◽  
The Mean ◽  
The Impact

Mudstones are often anisotropic, which complicates depth conversion in seismic exploration and monitoring subsurface reservoirs during injection or production. In addition, the physical and mechanical properties of mudstones are highly sensitive to their water content. The elastic anisotropy of mudstones is not well understood because of their complex nature and the lack of laboratory experiments performed on well-preserved samples. Triaxial deformation tests were performed on mudstone core plugs to investigate the impact of water saturation on the elastic anisotropy of the Whitby Mudstone (United Kingdom). The mechanical and physical properties of the Whitby Mudstone were estimated from stress-strain and ultrasonic wave velocity data obtained on core plugs with different water saturations under isotropic and anisotropic stress conditions. The Whitby Mudstone has extremely high intrinsic elastic anisotropy (0.3–0.4) due to its composition and lamination. This elastic anisotropy increases with decreasing water content. There are three competing mechanisms that play a key role in the anisotropy increase due to dehydration such as (1) density contrast in the pore space (i.e., the presence of purely brine or a mixture of brine and air in the pore space), (2) formation of dehydration fractures, and (3) frame stiffening. Increasing the mean effective stress leads to a decrease in Thomsen’s anisotropy parameters [Formula: see text] and [Formula: see text] because of the closure of defects, such as natural and dehydration fractures, and the formation of stress-induced fractures. The relationship between the wavefront anellipticity factor [Formula: see text] and the mean effective stress is nonmonotonic and can be related to the onset of inelastic deformation.

scholarly journals Apparent Permeability Model for Gas Transport in Multiscale Shale Matrix Coupling Multiple Mechanisms

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6323
Author(s):  
Xiaoping Li ◽  
Shudong Liu ◽  
Ji Li ◽  
Xiaohua Tan ◽  
Yilong Li ◽  
...  
Keyword(s):  
Pore Size ◽  
Water Distribution ◽  
Gas Transport ◽  
Water Saturation ◽  
Gas Permeability ◽  
Apparent Permeability ◽  
Permeability Model ◽  
Proposed Model ◽  
Irreducible Water Saturation ◽  
The Impact

Apparent gas permeability (AGP) is a significantly important parameter for productivity prediction and reservoir simulation. However, the influence of multiscale effect and irreducible water distribution on gas transport is neglected in most of the existing AGP models, which will overestimate gas transport capacity. Therefore, an AGP model coupling multiple mechanisms is established to investigate gas transport in multiscale shale matrix. First, AGP models of organic matrix (ORM) and inorganic matrix (IOM) have been developed respectively, and the AGP model for shale matrix is derived by coupling AGP models for two types of matrix. Multiple effects such as real gas effect, multiscale effect, porous deformation, irreducible water saturation and gas ab-/de-sorption are considered in the proposed model. Second, sensitive analysis indicates that pore size, pressure, porous deformation and irreducible water have significant impact on AGP. Finally, effective pore size distribution (PSD) and AGP under different water saturation of Balic shale sample are obtained based on proposed AGP model. Under comprehensive impact of multiple mechanisms, AGP of shale matrix exhibits shape of approximate “V” as pressure decrease. The presence of irreducible water leads to decrease of AGP. At low water saturation, irreducible water occupies small inorganic pores preferentially, and AGP decreases with small amplitude. The proposed model considers the impact of multiple mechanisms comprehensively, which is more suitable to the actual shale reservoir.

LABORATORY STUDIES OF SANDSTONE RESERVOIRS GAS DISPLACEMENT FROM HAVING STRONG WATER DRIVE

1974 ◽  
Vol 14 (1) ◽  
pp. 189 ◽  
Author(s):  
B. A. McKay
Keyword(s):  
Elevated Temperatures ◽  
Water Saturation ◽  
Pore Space ◽  
Sedimentary Basins ◽  
Water Flooding ◽  
Gas Saturation ◽  
Gas Recovery ◽  
Irreducible Water Saturation ◽  
Residual Gas ◽  
Residual Gas Saturation

Investigations by the Petroleum Technology Section of the Bureau of Mineral Resources have shown that a substantial residual gas saturation is trapped behind the flood front in gas-producing reservoirs having a strong water-drive; the volume of gas trapped may be as high as 44 per cent of pore space, and lies within the same range as residual oil saturation in a flooded-out oil reservoir.Core samples from gas-productive reservoirs in three Australian sedimentary basins have been subjected to laboratory tests to measure this effect. The tests comprised capillary pressure measurements, water-flooding by dynamic-displacement and imbibition at ambient and elevated temperatures, and repeat gas recovery measurements in core samples exhibiting variations in irreducible water saturation.The results show a loose correlation between porosity and residual gas behind the flood front in these samples. Temperature appears to have little effect on the residual gas saturation. Gas recovery, however, is strongly dependent on the irreducible water saturation established prior to flooding.

scholarly journals Insights, Trends and Challenges Associated with Measuring Coal Relative Permeability

2019 ◽  
Vol 89 ◽  
pp. 01004
Author(s):  
Dylan Shaw ◽  
Peyman Mostaghimi ◽  
Furqan Hussain ◽  
Ryan T. Armstrong
Keyword(s):  
Relative Permeability ◽  
Effective Stress ◽  
History Matching ◽  
Water Saturation ◽  
Laboratory Data ◽  
Stress Regime ◽  
Cross Point ◽  
Irreducible Water Saturation ◽  
Relative Permeability Curves ◽  
The Right

Due to the poroelasticity of coal, both porosity and permeability change over the life of the field as pore pressure decreases and effective stress increases. The relative permeability also changes as the effective stress regime shifts from one state to another. This paper examines coal relative permeability trends for changes in effective stress. The unsteady-state technique was used to determine experimental relativepermeability curves, which were then corrected for capillary-end effect through history matching. A modified Brooks-Corey correlation was sufficient for generating relative permeability curves and was successfully used to history match the laboratory data. Analysis of the corrected curves indicate that as effective stress increases, gas relative permeability increases, irreducible water saturation increases and the relative permeability cross-point shifts to the right.

Impact of formation and dissociation conditions on stiffness of a hydrate-bearing sand

2018 ◽  
Vol 55 (7) ◽  
pp. 988-998 ◽  
Author(s):  
Amit Sultaniya ◽  
Jeffrey A. Priest ◽  
C.R.I. Clayton
Keyword(s):  
Effective Stress ◽  
Pore Space ◽  
Hydrate Formation ◽  
Thermal Stimulation ◽  
Resonant Column ◽  
Rapid Reduction ◽  
Gas Recovery ◽  
Future Production ◽  
Hydrate Saturation ◽  
The Impact

Methane gas recovery from gas hydrate–bearing sands requires dissociation of the hydrate. Understanding changes in the stiffness of the sand is essential if future production scenarios are to be modelled realistically. This paper reports the results of resonant column tests conducted to measure changes in shear and flexural Young’s modulus (stiffness) of sand specimens during the formation and dissociation of hydrate within the pore space. Factors such as hydrate saturation, effective stress, and dissociation method (thermal stimulation and depressurization) were evaluated. Results show a nonlinear relationship between stiffness and hydrate volume, with hydrate formation and dissociation giving markedly different changes in stiffness. Stiffness increases more slowly during the initial stages of hydrate formation, compared to later stages, with the eventual stiffness being independent of the effective stress applied at the start of formation. In contrast, the onset of dissociation leads to a rapid reduction in stiffness, with thermal stimulation giving a greater reduction compared to depressurization for similar changes in hydrate volume. These results highlight the impact of hydrate morphology on changes in stiffness during the hydrate formation process or its dissociation. We present and discuss a conceptual model to explain the differences observed.

A Comprehensive Approach for Assessing the Impacts of Wettability on Oil Production in Carbonate Reservoirs

2012 ◽  
Author(s):  
Marcos Faerstein ◽  
Paulo Couto ◽  
José Alves
Keyword(s):  
Capillary Pressure ◽  
Case Studies ◽  
Water Saturation ◽  
Oil Production ◽  
Comprehensive Approach ◽  
Carbonate Reservoirs ◽  
Irreducible Water Saturation ◽  
Reservoir Simulator ◽  
Correct Understanding ◽  
The Impact

This paper discusses the impacts that rock wettability may have upon the production and recovery of oil with waterflooding in carbonate reservoirs and how it should be modeled. A broad review of the state of the art has been conducted surveying existing disagreements and knowledge gaps, basic definitions, as well as the correct understanding of the physical phenomena and identification of the characteristics of the various wettability scenarios. Case studies conducted with a black oil reservoir simulator evaluated the impact of different wettability scenarios on oil production and recovery. A comprehensive approach considering all the parameters involved in the wettability modeling was applied to the case studies, showing how the behavior of the reservoir varies as a function of their wettability. This paper shows how relative permeability and capillary pressure should be varied to correctly represent different wettability scenarios and consequently assess its impacts on oil production and recovery. The case studies show that the evaluation of the volume of oil in the reservoir is impacted by wettability through the irreducible water saturation and primary drainage capillary pressure and must be considered in the analyses. In long term analyses, mixed-wet scenarios have a higher oil production and recovery. In medium and short term, the water-wet scenarios have the higher recovery, but in relation to oil production, these scenarios are negatively influenced by the smaller volume of oil in place. The main contribution of this paper is the simultaneous analyses of all the parameters involved in the modeling of wettability showing how they impact the behavior of a reservoir. It shows how the parameters must be varied in a heterogeneous reservoir and how heterogeneity impacts the relevance of wettability in the studies.

Formation Evaluation With NMR, Resistivity, and Pressure Data: A Case Study of a Carbonate Oil Field Off shore West Africa

2021 ◽  
Vol 62 (1) ◽  
pp. 73-88
Author(s):  
Ting Li ◽  
◽  
Nicholas Drinkwater ◽  
Karen Whittlesey ◽  
Patrick Condon ◽  
...  
Keyword(s):  
West Africa ◽  
Water Saturation ◽  
Pore Space ◽  
Free Water ◽  
Total Porosity ◽  
Poor Quality ◽  
Oil Field ◽  
Water Volume ◽  
Pressure Gradients ◽  
Irreducible Water Saturation

In this paper, we examine fluids interpretation techniques in a prolific oil field in offshore West Africa. A sourceless logging program, consisting of logging-while-drilling (LWD) nuclear magnetic resonance (NMR), resistivity, and formation tester, was chosen to log the reservoir section in 6.5-in. holes. The purpose of this study is to answer questions related to asset appraisal and development with these limited measurements. Core data available are porosity, permeability, water salinity, Archie m and n, and Dean-Stark Sw. A comparison of the core and NMR log indicates that NMR total porosity is not affected by hydrocarbon in the pore space. We use a statistical method called factor analysis to deconvolve independent fluid modes from the T2 distribution and pick the T2 cutoff. The NMR irreducible water saturation (Swirr) computed with this cutoff agrees with Dean-Stark Sw. Continuous Sw is calculated with Archie’s equation with lab-measured parameters and validated against Dean-Stark Sw above the transition zone. The Timur-Coates model is used to estimate matrix permeability. The first application of this interpretation workflow is to confirm the free-water level (FWL) derived from pressure gradients. We found the Sw profile largely controlled by heterogeneity in rock textures. The presence of both good and poor-quality rocks makes log-based FWL picking difficult. We use Swirr from NMR to indicate rock quality and simplify our final interpretation. The FWL found by sourceless log interpretation is consistent with the initial FWL found by pressure gradients. The second application is perforation design. Zones with good porosity and low mobile water volume are selected for perforation, and a safe distance is maintained from FWL. As a result, all producer wells exhibit zero water cut.

scholarly journals The Controls of Pore-Throat Structure on Fluid Performance in Tight Clastic Rock Reservoir: A Case from the Upper Triassic of Chang 7 Member, Ordos Basin, China

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Yunlong Zhang ◽  
Zhidong Bao ◽  
Fei Yang ◽  
Shuwei Mao ◽  
Jian Song ◽  
...  
Keyword(s):  
Water Saturation ◽  
Pore Space ◽  
Ordos Basin ◽  
Significant Proportion ◽  
Pore Throat ◽  
Tight Sandstone ◽  
Clastic Rock ◽  
Control Factors ◽  
Significant Difference ◽  
The Impact

The characteristics of porosity and permeability in tight clastic rock reservoir have significant difference from those in conventional reservoir. The increased exploitation of tight gas and oil requests further understanding of fluid performance in the nanoscale pore-throat network of the tight reservoir. Typical tight sandstone and siltstone samples from Ordos Basin were investigated, and rate-controlled mercury injection capillary pressure (RMICP) and nuclear magnetic resonance (NMR) were employed in this paper, combined with helium porosity and air permeability data, to analyze the impact of pore-throat structure on the storage and seepage capacity of these tight oil reservoirs, revealing the control factors of economic petroleum production. The researches indicate that, in the tight clastic rock reservoir, largest throat is the key control on the permeability and potentially dominates the movable water saturation in the reservoir. The storage capacity of the reservoir consists of effective throat and pore space. Although it has a relatively steady and significant proportion that resulted from the throats, its variation is still dominated by the effective pores. A combination parameter (ε) that was established to be as an integrated characteristic of pore-throat structure shows effectively prediction of physical capability for hydrocarbon resource of the tight clastic rock reservoir.

scholarly journals Impact of Petrophysical Properties on Hydraulic Fracturing and Development in Tight Volcanic Gas Reservoirs

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Yinghao Shen ◽  
Mianmo Meng ◽  
Tao Liu ◽  
Hongkui Ge ◽  
Yuelei Zhang
Keyword(s):  
Hydraulic Fracturing ◽  
Water Saturation ◽  
Spontaneous Imbibition ◽  
Petrophysical Properties ◽  
Gas Reservoirs ◽  
Volcanic Gas ◽  
Volcanic Reservoir ◽  
Fracturing Fluids ◽  
Irreducible Water Saturation ◽  
Fast Flow

The volcanic reservoir is an important kind of unconventional reservoir. The aqueous phase trapping (APT) appears because of fracturing fluids filtration. However, APT can be autoremoved for some wells after certain shut-in time. But there is significant distinction for different reservoirs. Experiments were performed to study the petrophysical properties of a volcanic reservoir and the spontaneous imbibition is monitored by nuclear magnetic resonance (NMR) and pulse-decay permeability. Results showed that natural cracks appear in the samples as well as high irreducible water saturation. There is a quick decrease of rock permeability once the rock contacts water. The pores filled during spontaneous imbibition are mainly the nanopores from NMR spectra. Full understanding of the mineralogical effect and sample heterogeneity benefits the selection of segments to fracturing. The fast flow-back scheme is applicable in this reservoir to minimize the damage. Because lots of water imbibed into the nanopores, the main flow channels become larger, which are beneficial to the permeability recovery after flow-back of hydraulic fracturing. This is helpful in understanding the APT autoremoval after certain shut-in time. Also, Keeping the appropriate production differential pressure is very important in achieving the long term efficient development of volcanic gas reservoirs.

Investigation on the control of multiphase flow behavior in a continuous casting tundish during ladle change

2020 ◽  
Vol 117 (6) ◽  
pp. 619
Author(s):  
Rui Xu ◽  
Haitao Ling ◽  
Haijun Wang ◽  
Lizhong Chang ◽  
Shengtao Qiu
Keyword(s):  
Multiphase Flow ◽  
Flow Behavior ◽  
Rolled Strip ◽  
Impact Zone ◽  
Steel Cleanliness ◽  
Carry Over ◽  
Slag Carry Over ◽  
Hot Rolled ◽  
Turbulence Inhibitor ◽  
The Impact

The transient multiphase flow behavior in a single-strand tundish during ladle change was studied using physical modeling. The water and silicon oil were employed to simulate the liquid steel and slag. The effect of the turbulence inhibitor on the slag entrainment and the steel exposure during ladle change were evaluated and discussed. The effect of the slag carry-over on the water-oil-air flow was also analyzed. For the original tundish, the top oil phase in the impact zone was continuously dragged into the tundish bath and opened during ladle change, forming an emulsification phenomenon. By decreasing the liquid velocities in the upper part of the impact zone, the turbulence inhibitor decreased considerably the amount of entrained slag and the steel exposure during ladle change, thereby eliminating the emulsification phenomenon. Furthermore, the use of the TI-2 effectively lowered the effect of the slag carry-over on the steel cleanliness by controlling the movement of slag droplets. The results from industrial trials indicated that the application of the TI-2 reduced considerably the number of linear inclusions caused by ladle change in hot-rolled strip coils.

Sign in / Sign up

Export Citation Format

Share Document