Measured Permeability Values Research Articles

Petrophysical and geomechanical characteristics of Canadian tight oil and liquid-rich gas reservoirs: I. Pore network and permeability characterization

Abstract The results from an ongoing laboratory study investigating petrophysical characteristics of the Montney and Bakken formations in Canada are presented. The primary objectives are to (1) characterize the pore network (porosity, pore size distribution) and fluid transport (permeability) properties of these formations in areas with limited datasets and (2) analyze the effects of different geological factors on porosity, pore size distribution and permeability. The techniques used for characterization include: Rock–Eval pyrolysis; bitumen reflectance (BRo); grain size measurement; helium pycnometry; low-pressure gas (N2) adsorption (surface area, pore size distribution); pressure-decay profile permeability, pulse-decay and crushed-rock gas (N2, He) permeability and fracture permeability tests. Rock–Eval analysis and microscopic observations indicate that most samples are organic-lean (average TOC content: 0.3 wt.%), ranging from fine-grained siltstone to very fine-grained sandstone (grain size range: 27–53.7 μm). The measured permeability values on core plugs increase with increasing porosity (2.1–14.1%), ranging between 3.3 ⋅ 10−6 and 7.3 ⋅ 10−2 mD. For the core plugs analyzed (“as-received”), profile (probe) permeability values (9.2 ⋅ 10−4–7.3·10−2 mD) are consistently higher than pulse-decay (1.6 ⋅ 10−5–3.9 ⋅ 10−2 mD) and crushed-rock (3.3 ⋅ 10−6–4.6 ⋅ 10−5 mD) permeability values. Corrected profile (probe) permeability values for “in-situ” effective stress (5.3 ⋅ 10−5–2.5 ⋅ 10−2 mD) are, however, comparable with the pulse-decay (1.6 ⋅ 10−5–3.9 ⋅ 10−2 mD) permeability values. Unpropped fracture permeability, determined using an innovative procedure in this work, can be significantly (up to eight orders of magnitude) higher than matrix permeability under similar effective stress conditions. The grain size data are correlated to permeability values. The dominant pore throat diameter controlling fluid flow is estimated for all samples using Winland-style correlations; these values agree with those obtained from low-pressure N2 adsorption analysis. Applying multiple analysis techniques on a large number of samples (26 m of slabbed core, 22 core plugs and their accompanying cuttings), this study provides a comprehensive petrophysical characterization of Montney and Bakken tight oil and liquid-rich gas reservoirs in Canada.

Lithological and diagenetic restrictions on biogenic gas generation in Songliao Basin inferred from grain size distribution and permeability measurement

Abstract Organically rich immature source rocks occur commonly at shallow burial depths in Songliao Basin, NE China. This has led to the general assumption that there must be a large biogenic gas resource in these organic rich, shallow strata. However, except for a few small gas fields that are generally associated with biodegraded oil, only a small amount of biogenic gas has been discovered. In order to determine the geological factors controlling biogenic gas generation and accumulation, a suite of potential source rock shale samples from burial depth less than 1600 m was analyzed for organic composition, grain size distribution and permeability. The results show that selected samples are organic rich and thermally immature. The grain size analysis shows a mixed distribution of silt and clay with D10 generally below 1.6 μm. The measured permeability values are generally below 1 μd under in situ stress conditions with pore throats that are most likely smaller than that of methanogenic bacteria. Very low permeability and very small pores resulting from compaction and diagenesis restrict bacteria movement and activity, limit nutrient transport, diminish space availability, and lead to a reduced biodiversity. Currently, no microbes can survive in these Cretaceous shales even though the shales never reached geopasturization temperatures and there is sufficient substrate. Biogenic gas generation is inferred to be restricted to near surface strata while elsewhere in this succession methanogenesis has ceased, which significantly reduces the exploration potential for biogenic gas.

Gas hydrate dissociation affecting the permeability and consolidation behaviour of deep sea host sediment

Gas hydrate dissociation is known to affect the permeability and the mechanical properties of the deep sea host sediments. Sediment permeability and compressibility changes occurring during hydrates dissociation might put its integrity under risk. The aforementioned effects were studied experimentally on treated clayish sediments, which were retrieved from the Amsterdam subsea mud volcano (MV).The Amsterdam MV is located in the Eastern Mediterranean Sea. Previous explorations to this area have discovered gas hydrates just 40 cm below the sea floor, at water depths of 2000 m and seabed temperatures between 12 and 14 °C. Gas hydrates formed in such warm environments become notably sensitive if the temperature were to increase any further.Laboratory tests were conducted with multi-component gas hydrates formed in the pore space of the treated sediment. Contrary to what was expected, hydrate dissociation was found to bear a moderate effect on the permeability of the sediment. The measured permeability values with and without hydrates appeared to be of the same order of magnitude. In contrast to permeability, the consolidation behaviour of the host formation was severely affected by the dissociation of the gas hydrate. Consolidation was observed to reach its maximum close to the hydrate stability region and it then collapsed as conditions fell beyond the stability limit.The results indicate that gradual dissociation of the hydrates could bear significant impact on the host deep-sea sediments thus confirming the role of hydrate dissociation as a possible cause of subsea landslides.

An evaluation of the reproducibility of capacitive sensor based in-plane permeability measurements: A benchmarking study

A benchmark study for permeability measurement is presented. In the past studies of other research groups which focused on the reproducibility of 1D-permeability measurements showed high standard deviations of the gained permeabil- ity values (25%), even though a defined test rig with required specifications was used. Within this study, the reproducibility of capacitive in-plane permeability testing system measurements was benchmarked by comparing results of two research sites using this technology. The reproducibility was compared by using a glass fibre woven textile and carbon fibre non crimped fabric (NCF). These two material types were taken into consideration due to the different electrical properties of glass and carbon with respect to dielectric capacitive sensors of the permeability measurement systems. In order to deter- mine the unsaturated permeability characteristics as function of fibre volume content the measurements were executed at three different fibre volume contents including five repetitions. It was found that the stability and reproducibility of the pre- sented in-plane permeability measurement system is very good in the case of the glass fibre woven textiles. This is true for the comparison of the repetition measurements as well as for the comparison between the two different permeameters. These positive results were confirmed by a comparison to permeability values of the same textile gained with an older gen- eration permeameter applying the same measurement technology. Also it was shown, that a correct determination of the grammage and the material density are crucial for correct correlation of measured permeability values and fibre volume contents.

Associating X-Ray Microtomography with Permeability Contrasts in Bioturbated Media

The use of X-ray microtomography (micro-CT) to evaluate the contrasts in permeability associated with bioturbation in two- and three-dimensions (2D and 3D) is investigated in this article. Core analysis, spot-permeametry measurements, and petrographic thin-sections of the six different datasets from Western Canada (Debolt Formation, Wabamun Group, and Medicine Hat Member) and offshore Norway (Ula Formation, Lysing Formation, and Nise Formation) show that the trace fossils commonly modify the permeability and porosity of the reservoir through sediment reworking and diagenesis of the sediment. In this study, micro-CT techniques are used to analyze the X-ray attenuation associated with bioturbation in siliciclastics and carbonates. Because X-ray attenuation represents the transmissivity or absorptivity of a sample to the incident X-rays, each of which is related to sediment composition and sediment densities, micro-CT images are integrated with sedimentological data and petrographic data to identify the trace fossils and matrix in 2D and 3D. Due to the difference in sediment grain size and sorting (i.e., porosity) within the burrows and matrix, analysis of the X-ray attenuations allows for their delineation in 2D cross-sectional images. When processed as 3D volumes, the micro-CT images show the complexity in burrow connectivity and burrow orientations within a sample. More importantly, the 3D volumes help show the distribution of porosity that can be linked to measured permeability values within a sample. Quantification of the heterogeneous burrow fabric on reservoir and resource quality is made from these processed micro-CT images.

An induction method to calculate the complex permeability of soft magnetic films without a reference sample

A new analytical method has been proposed by utilizing an electromagnetic induction principle with a short-circuited microstrip line jig and the complex permeability spectra can be calculated without a known reference sample. The new method using the short-circuited microstrip line can exhibit higher sensitivity and a wider frequency band than coplanar waveguide and pick-up coil. Two magnetic thin films having a good in-plane uniaxial anisotropy are measured by using the induction method. The results show typical complex permeability spectra in good agreement with the theoretical analytical results. The measured permeability values are verified by comparing with the initial susceptibility derived from the sweeping field results. The difference of measured permeability values is less than 5%.

Measurement of Longwall Mining Induced Strata Permeability

The paper summarizes the findings of the underground permeability measurements (using inflatable packers) undertaken at a mine site in New South Wales in Australia and highlights the difficulties encountered during packer testing. The research project was supported by the Australian Coal Association Research Project. Within this project, systematic sub-surface and underground hydrogeological monitoring and measurements were carried out e.g. underground packer tests and piezometer, extensometer, and water inflow monitoring during mining. The project was aimed at investigating the effects of longwall mining on strata pore pressure, permeability, and water inflow to facilitate prediction of mining induced aquifer interference and mine water inflow. This paper presents only the results of underground permeability tests conducted at the mine site. The tests show that the drivage of main headings (roadways) can induce a significant change in permeability into the solid coal barrier. Permeability can be seen to increase by as much as 50 times at a distance of 11.2–11.5 m from the roadway rib. The measured permeability values varied widely and strangely on a number of occasions; for example the test conducted from the main headings at 8.2–8.5 m test section in the solid coal barrier showed a decline in permeability value compared to that at 11.2–11.5 m section contrary to the expectations. The tests conducted in the roof strata near (above) the longwall goaf indicated a possibility of more than 1,000 fold increase in permeability. Though the underground packer testing appears to be a good technique for measuring in situ permeability of rocks and coal seams, the study highlighted that (1) boreholes for packer testing need to be drilled with extreme care so as to avoid any undue damage or smearing of the borehole wall and (2) a sufficient number of tests at a number of locations needs to be conducted to cater for the possible variations of the test results.

Modelling of Longwall Mining-Induced Strata Permeability Change

The field measurement of permeability within the strata affected by mining is a challenging and expensive task, thus such tests may not be carried out in large numbers to cover all the overburden strata and coal seams being affected by mining. However, numerical modelling in conjunction with a limited number of targeted field measurements can be used efficiently in assessing the impact of mining on a regional scale. This paper presents the results of underground packer testing undertaken at a mine site in New South Wales in Australia and numerical simulations conducted to assess the mining-induced strata permeability change. The underground packer test results indicated that the drivage of main headings (roadways) had induced a significant change in permeability into the solid coal barrier. Permeability increased by more than 50 times at a distance of 11.2–11.5 m from the roadway rib into the solid coal barrier. The tests conducted in the roof strata above the longwall goaf indicated more than 1,000-fold increase in permeability. The measured permeability values varied widely and strangely on a number of occasions; for example the test conducted from the main headings at the 8.2–8.5 m test section in the solid coal barrier showed a decline in permeability value as compared to that at the 11.2–11.5 m section contrary to the expectations. It is envisaged that a number of factors during the tests might have had affected the measured values of permeability: (a) swelling and smearing of the borehole, possibly lowering the permeability values; (b) packer bypass by larger fractures; (c) test section lying in small but intact (without fractures) rock segment, possibly resulting in lower permeability values; and (d) test section lying right at the extensive fractures, possibly measuring higher permeability values. Once the anomalous measurement data were discarded, the numerical model results could be seen to match the remaining field permeability measurement data reasonably well.

2D and 3D imaging resolution trade-offs in quantifying pore throats for prediction of permeability

Although the impact of subsurface geochemical reactions on porosity is relatively well understood, changes in permeability remain difficult to estimate. In this work, pore-network modeling was used to predict permeability based on pore- and pore-throat size distributions determined from analysis of 2D scanning electron microscopy (SEM) images of thin sections and 3D X-ray computed microtomography (CMT) data. The analyzed specimens were a Viking sandstone sample from the Alberta sedimentary basin and an experimental column of reacted Hanford sediments. For the column, a decrease in permeability due to mineral precipitation was estimated, but the permeability estimates were dependent on imaging technique and resolution. X-ray CT imaging has the advantage of reconstructing a 3D pore network while 2D SEM imaging can easily analyze sub-grain and intragranular variations in mineralogy. Pore network models informed by analyses of 2D and 3D images at comparable resolutions produced permeability estimates with relatively good agreement. Large discrepancies in predicted permeabilities resulted from small variations in image resolution. Images with resolutions 0.4 to 4μm predicted permeabilities differing by orders of magnitude. While lower-resolution scans can analyze larger specimens, small pore throats may be missed due to resolution limitations, which in turn overestimates permeability in a pore-network model in which pore-to-pore conductances are statistically assigned. Conversely, high-resolution scans are capable of capturing small pore throats, but if they are not actually flow-conducting predicted permeabilities will be below expected values. In addition, permeability is underestimated due to misinterpreting surface-roughness features as small pore throats. Comparison of permeability predictions with expected and measured permeability values showed that the largest discrepancies resulted from the highest resolution images and the best predictions of permeability will result from images between 2 and 4μm resolution. To reduce permeability underestimation from analyses of high-resolution images, a resolution threshold between 3 and 15μm was found to be effective, but it is not known whether this range is applicable beyond the samples studied here.

Platelet-Rich Blood Clots

To determine how the volume fraction of fibrin and platelets affects fluid transport within the interstitial spaces of blood clots, the article in this issue by Wufsus et al. (1xThe hydraulic permeability of blood clots as a function of fibrin and platelet density. Wufsus, A.R., Macera, N.E., and Neeves, K.B. Biophys. J. 2013; 104: 1812–1823Abstract | Full Text | Full Text PDF | PubMed | Scopus (26)See all References1) presents a study of platelet-rich clots (characteristic of the initial stages of hemostatic and thrombotic clots) in which both granular (platelets) and fibrous (fibrin) media are present. The permeability of a clot was estimated by assuming a Darcy’s law approximation at the macroscopic scale and measuring flow through the clots under a maintained constant pressure gradient. Measured permeability values were compared to models of fibrous, granular, and mixed porous media to delineate the relative contributions of each component to the overall hydrodynamic resistance. Confocal microscopy was used to determine the volume fraction of the fibrin gels and platelet-fibrin thrombi, and scanning electron microscopy was used to measure fiber diameters.Permeability measurements are typically used to determine how biochemical conditions affect fibrin polymerization. For example, for a given fibrinogen concentration, fibrin gels formed at higher thrombin concentrations consist of more densely packed thin fibers than in gels formed at low thrombin concentrations. Permeability has also been used as a measure of how a drug or certain disorders affect fibrin polymerization.For fibrin gels, a large (three orders of magnitude) decrease in permeability was found for a modest increase in volume fraction (0.02–0.18), and a much smaller change in permeability for volume fractions in the range 0.18–0.54. These observations were compared with the relationships among fibrin gel permeability, fiber volume fraction, and fiber radius established empirically or derived from simplified analytic (2xFlow through mixed fibrous porous materials. Ethier, C.R. AIChE J. 1991; 37: 1227–1236Crossref | Scopus (31)See all References2) or detailed numerical (lattice-Boltzmann) solutions (3xHydraulic permeability of (un)bounded fibrous media using the lattice Boltzmann method. Clague, D.S., Kandhai, B.D...., and Sloot, P.M. Phys. Rev. E Stat. Phys. Plasmas Fluids Relat. Interdiscip. Topics. 2000; 61: 616–625Crossref | PubMed | Scopus (83)See all References3). The conclusion is that, over a fiber volume fraction of 0.02–0.54, fibrin gels are well described by models of disordered cylinders with uniform diameters.When platelets were added at a volume fraction of 0.19–0.31, the permeability decreased by only ∼50%, compared to a pure fibrin gel. At higher platelet volume fractions (>0.31), however, the contribution of the platelets begins to dominate the overall hydraulic resistance (permeability is an order of magnitude lower at a platelet volume fraction of 0.37). A platelet-rich clot was found to be well described as a Brinkman medium (the Brinkman equation adds a dissipative term to the Darcy equation, arising from the no-slip fluid boundary condition on the surface of large solid inclusions). Viscous losses alone, however, do not fully account for the effect of the addition of platelets into a fibrin gel. Platelets affect fibrin polymerization, and fibers in the presence of platelets are more tortuous and appear much shorter than in platelet-poor plasma.

Reliable permeability assay system in a microfluidic device mimicking cerebral vasculatures

Since most of the bioavailable drugs are impermeable through the blood-brain barrier (BBB), development of a rapid and reliable permeability assay system has been a challenge in drug discovery targeting central nervous system (CNS). Here, we designed a microfluidic device to monitor the drug permeability into the CNS. Human umbilical vein endothelial cells (HUVECs) were shortly (2 ~ 3 h) incubated with astrocyte-conditioned medium after being trapped on microholes in the microfluidic device and tested for chip-based permeability measurement of drugs. The measured permeability values were highly correlated with those measured by conventional in vitro methods and the brain uptake index representing the quantity of transported substances across the in vivo BBB of rats. Using the microfluidic device, we could easily monitor the effect of hydrogen peroxide on the trans-endothelial permeability, which are consistent with the finding that the same treatment disrupted the formation of tight junctions between endothelial cells. Considering relatively short period of time needed for endothelial cell culture and ability to monitor the BBB physiology continuously, we propose that this novel system can be used as an invaluable first-line tool for CNS-related drug development.

Permeability of shale by the beam-bending method

The beam-bending method permits measurement of liquid permeability in the nanoDarcy range in a few minutes to a few hours. This technique has been applied successfully to determine the permeability, as well as the viscoelastic properties, of isotropic materials with low permeability, such as gels, porous glass, and cement paste. The method has been extended to measure transversely anisotropic materials, such as sedimentary rock, to find the permeability parallel and perpendicular to the bedding. In this study, measurements have been made on a set of shales from varying depths and locations in the continental United States. The measured permeabilities range 0.009–400 nanoDarcies (nD=10−21m2). The permeability in the direction parallel to the bedding orientation was larger than that perpendicular to the bedding orientation, by a factor ranging from 1.2 to 6. This is the first instance of using the beam-bending method to measure the permeabilities of shale in different orientations.The measured permeabilities were compared to the Kozeny–Carman and Katz–Thompson models. The pore geometry parameters used in the models, such as the pore size distribution, characteristic pore diameters, porosity, and tortuosity were measured using mercury intrusion porosimetry (MIP), gravimetry, and electrical conductivity, respectively. The measured permeability values match better with the predictions from the Katz–Thompson equation.

Pd-based membrane reactors for producing ultra pure hydrogen: Oxidative reforming of bio-ethanol

A membrane reactor consisting of a dense self-supported Pd–Ag tube of wall thickness 60 μm has been filled with a Pt-based catalyst and used for producing pure hydrogen via oxidative steam reforming of bio-ethanol. The reformer feed stream consisted of water and ethanol with traces of glycerol and acetic acid in order to simulate a liquid waste of dairy industry after fermentation and concentration.The membrane reformer has been characterized through permeation and reaction tests performed at 400 and 450 °C with a reaction (lumen) pressure in the range 100–200 kPa. The hydrogen permeated through the membrane has been collected in the reactor shell by a sweep stream of nitrogen.Permeation tests verified the complete hydrogen selectivity of the thin wall tube membrane and measured permeability values at 400–450 °C of 1–2 mol m−1 s−1 Pa−0.5 accordingly to the literature.In the reaction tests, the capability of the membrane to promote the reaction conversion (shift effect) has been demonstrated. The gas chromatographic analysis of the retentate showed very low concentration of CO and the presence of methane as a main product of side-reactions. At 400 °C the pressure affects significantly the hydrogen production and the hydrogen yield moves from 0.4 to 1 when the pressure increases from 100 to 200 kPa. Significant increase of the hydrogen production has been attained at the higher temperature of 450 °C where maximum values of hydrogen yield (close to 3) have been measured with a lumen pressure of 200 kPa. Under these conditions, the technology of Pd-based membranes is effective for recovering hydrogen from a liquid waste.

Investigation of temperature effect on permeability of naturally fractured black coal for carbon dioxide movement: An experimental and numerical study

Very deep coal seams which are unlikely to be mined may be considered for CO2 sequestration. The main objective of this study is to investigate the effect of temperature on the permeability of naturally fractured coal. Permeability tests were conducted on naturally fractured bituminous coal samples using high pressure triaxial equipment for five different injecting pressures (8–13MPa) under two different confinements (20 and 24MPa) and five different temperatures (25–70°C). The experimental data were then used to develop an appropriate numerical model using the COMET 3 simulator to model the temperature effect on permeability at temperatures up to 200°C. According to the measured permeability values and the developed lab-scale model, there is a clear increase in CO2 permeability with increasing temperature for any confining pressure at high injecting pressures (more then 10MPa). However, for low injecting pressures (less than 9MPa) temperature effect is not so much. With increasing injecting pressure, CO2 permeability decreases at low temperatures (less than around 40°C), and increases at high temperatures (more than 50°C). Interestingly, the temperature effect on permeability is significant only up to around 90°C condition within the 25–200°C temperature limit. These observations are related with the sorption behavior of the adsorbing CO2 during the injection. However, there is no noticeable temperature effect on N2 permeability as it does not create any swelling effect in coal matrix.

Characterization and modelling of a dense lamella formed during self-compression of fibrillar collagen gels: implications for biomimetic scaffolds

The three dimensional microstructure and fluid conductivity of hydrogels are major determinants of their physical and mechanical properties. Under free fluid flow conditions, highly hydrated fibrillar collagen gels expel fluid and undergo a gravity driven consolidation process (self-compression). Within minutes of the initiation of self-compression, collagen scaffolds with fibrillar densities resembling those of native tissues are produced. However, the microstructural and mechanical processes responsible for collagen gel consolidation have not been fully investigated. During self-compression of collagen gels, a thin, high density lamella of collagen forms at the fluid expulsion boundary thereby generating a two-layer structure. By applying Darcy's law to model fluid flow in the two-layer structure, a novel method was developed to measure the hydraulic permeability of hydrated collagen gels as a function of gel mass loss. Experimentally measured permeability values of the lamella ranged from 4.3 × 10−15 to 1.2 × 10−14 m2 which were 100 to 1000-fold less than those of the hydrated collagen layer. These experimental data were in close agreement with permeability values estimated by the Happel model. Scanning electron and confocal laser scanning microscopy each confirmed the presence of a two-layer structure beyond three minutes of self-compression. Therefore, the formation of a dense lamella characterized by a significantly reduced hydraulic permeability modulates the kinetics of consolidation, as well as the microstructure of fibrillar collagen gels. This provides important implications and functional significance in the processing of multi-layered biomimetic tissue equivalent collagen based scaffolds and drug delivery systems.

Lattice‐Boltzmann modeling of the air permeability of polar firn

Recent advances in three‐dimensional (3D) imaging of snow and firn combined with numerical modeling of flow through complex geometries have greatly improved the ability to predict permeability values based on microstructure. In this work, we combined 3D reconstructions of polar firn microstructure obtained from microcomputed tomography (μCT) and a 3D lattice‐Boltzmann (LB) model of air flow. We compared the modeled results to measurements of permeability for polar firn with a wide range of grain and pore‐scale characteristics. The results show good agreement between permeability measurements and calculated permeability values from the LB model over a wide range of sample types. The LB model is better at predicting measured permeability values than traditional empirical equations for polar firn.

Characterization of a Complex Carbonate Heavy-Oil Reservoir

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 120423, ’Characterization of Complex Carbonate Heavy Oil Reservoir - A Case Study,’ by Afzal Iqbal,John Smith, Ali Reza Zahedi, Deemer Arthur, and Falah M. Al-Yami, Saudi Arabian Chevron; W. Scott Meddaugh, Chevron Energy Technology Company; Mansoor A. Rampurawala, SPE, Bingjian Li, SPE, and Ihsan Gok, SPE, Schlumberger Oilfield Services; and Talal Al Enazi, Kuwait Gulf Oil Company, originally prepared for the 2009 SPE Middle East Oil and Gas Show and Conference, Bahrain, 15-18 March. The First Eocene reservoir is the shallowest producing interval of the Wafra field in the partitioned Neutral Zone between Saudi Arabia and Kuwait. Characterization of this heavy-oil reservoir is challenging because of observed variations in oil viscosity, heterogeneity related to complex mineralogy, a possible dual-porosity system, and the presence of fractures of varing scales. The full-length paper presents several aspects of an integrated approach to characterize the reservoir. Introduction Currently, a large-scale steamflood pilot (LSP) consisting of sixteen 2.5-acre inverted-5-spot patterns is being installed. This will be the first multipattern steamflood of a carbonate reservoir in the Middle East. Oil was discovered in the First Eocene in 1954, and full-scale development began in 1956. The First Eocene has produced only 4% of original oil in place (OOIP), and primary recovery is not expected to exceed 10%. The oil gravity in this heavy-oil reservoir varies from 14 to 20ºAPI. The First Eocene is a depletion-drive reservoir with partial solution-gas drive and limited aquifer support. The estimated gross OOIP within the currently delineated field limit is more than 10 billion reservoir bbl. The reservoir mainly consists of dolomitized packstones and grainstones deposited under arid-to-semiarid conditions on a shallow, very gently dipping, low- to moderate-energy inner shelf or ramp setting in a gently dipping, restricted ramp environment. The presence of minor interbedded evaporites suggests restriction was occasionally sufficient for the development of hypersaline lagoons and sabkhas. The shallowing-upward cycles are capped by mud-dominated rocks, hardgrounds, and exposure surfaces. The average porosity is 35% and the average permeability is 250 md over the gross interval. Well-log and core-plug porosity values greater than 50% are common, and measured permeability values range up to 5,000 md. The First Eocene reservoir has an average depth of approximately 1,000 ft and a gross thickness of approximately 750 ft. Three wells were used in the study to demonstrate the approach of integrating log and core data to evaluate reservoir heterogeneity.

Error Assessment in Permeability Measurement Using Radial Flow Method

Permeability values measured on textile reinforcements with different methods or different test set-ups can differ significantly from each other. Even measurements preformed on the same test set-up can have a substantial scatter of measured permeability values. This paper discusses the sources of possible measurement errors for a radial flow set-up and their influence on the measured permeability results. Suggestions are given to improve the reliability of permeability measurements.

Investigation of a simple tensorial permeameter

AbstractA device to measure permeability tensors of aligned circular cylinder arrays was designed and tested. Experiments were performed on arrays having solid volume fractions ranging from 0.3 to 0.7, inclusive. Array structures had 60° (hexagonal), 70°, and 90° (square) angles of symmetry. Results for transverse flow across the cylinder arrays were in strong agreement with numerical predictions. Transverse permeability values were also shown to obey tensor transformation rules. Longitudinal test results indicated that transverse flow was present during the experiments, lowering measured permeability values. The influence of longitudinal permeability on the overall tensor was shown to be substantially larger than variations in the transverse permeability values. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers

Coefficient of consolidation from mid-plane pore pressure measurements

The values of coefficient of consolidation calculated based on time-settlement data from a laboratory consolidation test are influenced by both initial and secondary compression effects. The effect of secondary compression is predominant when the load increment ratio is less than 1.0. In this Note a method of estimation of coefficient of consolidation based on pore pressure measurement is suggested. Comparison of the values with those computed from independently measured permeability values shows closer agreement suggesting the validity of the proposed method. As time-settlement data is not used, the values are expected to be free from secondary compression effects.