Characterization of Fluid Connectivity in Reservoirs using Strontium Isotopes

2021 ◽  
Author(s):  
Stéphane Polteau ◽  
Farhana Huq ◽  
Craig Smalley ◽  
Viktoriya Yarushina ◽  
Ingar Johansen ◽  
...  
Keyword(s):  
Pore Space ◽  
Low Permeability ◽  
Pressure Measurements ◽  
Sedimentary Sequences ◽  
Mass Fractionation ◽  
Side Track ◽  
Natural Tracer ◽  
Internal Barriers ◽  
Norwegian Continental Shelf

<p>Routine measurements of formation pressure while drilling reservoirs can indicate the presence of internal barriers to vertical fluid movement when there is a sudden shift in the pressure data. However, pinpointing the location of a barrier is often not possible since the density of pressure measurements is low and irregular. The aim of this contribution is to show how the Strontium isotopic system can help characterize the fluid connectivity and pinpoint the precise location of low permeability barriers in reservoir units and sedimentary sequences. As an example, we use a 25 m thick interval within the Middle Jurassic Hugin reservoir unit of the Langfjellet oil discovery on the Norwegian Continental Shelf. The location of the barrier is constrained by the upper and lower pressure measurements and could correspond to any of the several layers of silt, shale or coal layers in this interval. In this study, we collected every 2-4 m a total of 40 samples from a 110 m long cored section of a technical side-track well over the available. Each sample was prepared and analyzed using the SrRSA method (Strontium Residual Salt Analysis), which measures the <sup>87</sup>Sr/<sup>86</sup>Sr ratio in salt residue that precipitated in the pore space after the core dried out. The <sup>87</sup>Sr/<sup>86</sup>Sr is a natural tracer because the ratio is not affected by mass fractionation. The <sup>87</sup>Sr/<sup>86</sup>Sr in rocks is mostly acquired by water-rock interactions during diagenesis and evolves through mixing and equilibration of different water bodies, unless low-permeability barriers prevent equilibration. Therefore, the SrRSA patterns observed in the well represent a 1D snapshot of the fluid dynamics at the time of oil filling, which is a frozen image of competing equilibrium vs disequilibrium conditions. The SrRSA data follow a smooth trend of content values at 0.713 and display a sudden jump to lighter 0.709 values near the top of the 25 m thick interval that suggests the presence of a potential barrier. The lithological core log shows that the SrRSA step change corresponds to a coal-shale unit, which is interpreted to represent the barrier. The SrRSA data further demonstrate the reservoir unit at Langfjellet does not contain any other barriers to fluid flow, since pressure equilibration could have masked a possible compartmentalization. This study shows that the SrRSA method is a powerful tool that should be routinely applied for the characterization of fluid connectivity of storage units.</p>

Aerodynamic Noise Characterization of a Full-Scale Wind Turbine through High-Frequency Surface Pressure Measurements

2015 ◽  
Vol 14 (5-6) ◽  
pp. 729-766 ◽  
Author(s):  
Franck Bertagnolio ◽  
Helge Aa. Madsen ◽  
Christian Bak ◽  
Niels Troldborg ◽  
Andreas Fischer
Keyword(s):  
Wind Turbine ◽  
Surface Pressure ◽  
High Frequency ◽  
Full Scale ◽  
Aerodynamic Noise ◽  
Pressure Measurements ◽  
Noise Characterization

Geomechanical aspects of induced microseismicity during CO2 injection in Illinois Basin

2021 ◽  
Vol 40 (11) ◽  
pp. 823-830
Author(s):  
Nikita Bondarenko ◽  
Sherilyn Williams-Stroud ◽  
Jared Freiburg ◽  
Roman Makhnenko
Keyword(s):  
Oil Field ◽  
Co2 Injection ◽  
Low Permeability ◽  
Illinois Basin ◽  
Petrographic Analysis ◽  
Flow Properties ◽  
Geomechanical Characterization ◽  
Fluid Penetration ◽  
Geophysical Log

Carbon sequestration activities are increasing in a global effort to mitigate the effects of greenhouse gas emissions on the climate. Injection of wastewater and oil-field fluids is known to induce seismic activity. This makes it important to understand how that risk relates to CO2 injection. Injection of supercritical CO2 into the Cambrian Mt. Simon sandstone in Illinois Basin induced microseismicity that was observed below the reservoir, primarily in the Precambrian crystalline basement. Geomechanical and flow properties of rock samples from the involved formations were measured in the laboratory and compared with geophysical log data and petrographic analysis. The controlling factors for induced microseismicity in the basement seem to be the hydraulic connection between the reservoir and basement rock and reactivation of pre-existing faults or fractures in the basement. Additionally, the presence of a laterally continuous low-permeability layer between reservoir and basement may have prevented downward migration of pore pressure and reactivation of critically stressed planes of weakness in the basement. Results of the geomechanical characterization of this intermediate layer indicate that it may act as an effective barrier for fluid penetration into the basement and that induced microseismicity is likely to be controlled by the pre-existing system of faults. This is because the intact material is not expected to fail under the reservoir stress conditions.

scholarly journals Analysis of Flow Instabilities on a Three-Bladed Axial Inducer in Fixed and Rotating Frames

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Giovanni Pace ◽  
Dario Valentini ◽  
Angelo Pasini ◽  
Ruzbeh Hadavandi ◽  
Luca d'Agostino
Keyword(s):  
Low Frequency ◽  
Flow Instabilities ◽  
Test Facility ◽  
Pressure Measurements ◽  
Dynamic Characterization ◽  
Rotating Frames ◽  
Induced Flow ◽  
High Head ◽  
Pump Inlet

The paper describes the results of recent experiments carried out in the Cavitating Pump Rotordynamic Test Facility for the dynamic characterization of cavitation-induced flow instabilities as simultaneously observed in the stationary and rotating frames of a high-head, three-bladed axial inducer with tapered hub and variable pitch. The flow instabilities occurring in the eye and inside the blading of the inducer have been detected, identified, and monitored by means of the spectral analysis of the pressure measurements simultaneously performed in the stationary and rotating frames by multiple transducers mounted on the casing near the inducer eye and on the inducer hub along the blade channels. An interaction between the unstable flows in the pump inlet and in the blade channels during cavitating regime has been detected. The interaction is between a low frequency axial phenomenon, which cyclically fills and empties each blade channel with cavitation, and a rotating phenomenon detected in the inducer eye.

The Effect of Capillary Condensation on the Geomechanical and Acoustic Properties of Tight Formations: An Experimental Study

2021 ◽  
Author(s):  
Aamer Albannay ◽  
Binh Bui ◽  
Daisuke Katsuki
Keyword(s):  
Pore Pressure ◽  
Capillary Condensation ◽  
Pore Space ◽  
Dew Point ◽  
Acoustic Properties ◽  
Point Pressure ◽  
Tight Formations ◽  
Dew Point Pressure ◽  
Compressional Velocity

Abstract Capillary condensation is the condensation of the gas inside nano-pore space at a pressure lower than the bulk dew point pressure as the result of multilayer adsorption due to the high capillary pressure inside the small pore throat of unconventional rocks. The condensation of liquid in nano-pore space of rock changes its mechanical and acoustic properties. Acoustic properties variation due to capillary condensation provides us a tool to monitor phase change in reservoir as a result of nano-confinement as well as mapping the area where phase change occurs as well as characterize pore size distribution. This is particularly important for tight formations where confinement has a strong effect on phase behavior that is challenging to measure experimentally. Theoretical studies have examined the effects of capillary condensation; however, these findings have not been verified experimentally. The main objective of this study is to experimentally investigate the effect of capillary condensation on the mechanical and acoustic properties of shale samples. The mechanical and acoustic characterization of the samples was carried out experimentally using a state-of-the-art tri-axial facility at the Colorado School of Mines. The experimental set-up is capable of the simultaneous acquisition of coupled stress, strain, resistivity, acoustic and flow data. Carbon dioxide was used as the pore pressure fluid in these experiments. After a comprehensive characterization of shale samples, experiments were conducted by increasing the pore pressure until condensation occurs while monitoring the mechanical and acoustic properties of the sample to quantify the effect of capillary condensation on the mechanical and acoustic properties of the sample. Experimental data show a 5% increase in Young's Modulus as condensation occurs. This increase is attributed to the increase in pore stiffness as condensation occurs reinforcing the grain contact. An initial decrease in compressional velocity was observed as pore pressure increases before condensation occurs which is attributed to the expansion of the pore volume when pore pressure increases. After this initial decrease, compressional velocity slightly increases at a pressure around 750 - 800 psi which is close to the condensation pressure. We also observed a noticeable increase in shear velocity when capillary condensation occurs, this could be due to the immobility of the condensed liquid phase at the pore throats. The changes of geomechanical and acoustic signatures were observed at around 750 - 800 psi at 27°C, which is the dew point pressure of the fluid in the nano-pore space of the sample at this temperature. While the unconfined bulk dew point pressure of carbon dioxide at the same temperature is 977 psi. Hence, this study marks the first measurement of the dew point of fluid in nano-pore space and potentially leads to the construction of the phase envelope of fluid under confinement.

Advances in low-field nuclear magnetic resonance (NMR) technologies applied for characterization of pore space inside rocks: a critical review

2020 ◽  
Vol 17 (5) ◽  
pp. 1281-1297 ◽  
Author(s):  
Jian-Chun Guo ◽  
Hang-Yu Zhou ◽  
Jie Zeng ◽  
Kun-Jie Wang ◽  
Jie Lai ◽  
...  
Keyword(s):  
Pore Space ◽  
Structure Characterization ◽  
Fluid Identification ◽  
Low Field ◽  
Signal Collection ◽  
History Of ◽  
Nmr Techniques ◽  
Future Work ◽  
Result Interpretation

Abstract NMR serves as an important technique for probing rock pore space, such as pore structure characterization, fluid identification, and petrophysical property testing, due to the reusability of cores, convenience in sample processing, and time efficiency in laboratory tests. In practice, NMR signal collection is normally achieved through polarized nuclei relaxation which releases crucial relaxation messages for result interpretation. The impetus of this work is to help engineers and researchers with petroleum background obtain new insights into NMR principals and extend existing methodologies for characterization of unconventional formations. This article first gives a brief description of the development history of relaxation theories and models for porous media. Then, the widely used NMR techniques for characterizing petrophysical properties and pore structures are presented. Meanwhile, limitations and deficiencies of them are summarized. Finally, future work on improving these insufficiencies and approaches of enhancement applicability for NMR technologies are discussed.

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