The Critical Role of In-Situ Pressure on Natural Fracture Shear and Hydraulic Fracturing-Induced Microseismicity Generation

2013 ◽  
Author(s):  
F. Zhang ◽  
Neal Borden Nagel ◽  
Marisela Sanchez-Nagel ◽  
Byungtark Lee ◽  
Alireza Agharazi
Keyword(s):  
Hydraulic Fracturing ◽  
Critical Role ◽  
Natural Fracture

Molecular modulation of calcium oxalate crystallization

2006 ◽  
Vol 291 (6) ◽  
pp. F1123-F1132 ◽  
Author(s):  
James J. De Yoreo ◽  
S. Roger Qiu ◽  
John R. Hoyer
Keyword(s):  
Molecular Modeling ◽  
Calcium Oxalate ◽  
Stone Formation ◽  
Energy Levels ◽  
Critical Role ◽  
Specific Interactions ◽  
Crystal Surfaces ◽  
Site Specific

Calcium oxalate monohydrate (COM) is the primary constituent of the majority of renal stones. Osteopontin (OPN), an aspartic acid-rich urinary protein, and citrate, a much smaller molecule, are potent inhibitors of COM crystallization at levels present in normal urine. Current concepts of the role of site-specific interactions in crystallization derived from studies of biomineralization are reviewed to provide a context for understanding modulation of COM growth at a molecular level. Results from in situ atomic force microscopy (AFM) analyses of the effects of citrate and OPN on growth verified the critical role of site-specific interactions between these growth modulators and individual steps on COM crystal surfaces. Molecular modeling investigations of interactions of citrate with steps and faces on COM crystal surfaces provided links between the stereochemistry of interaction and the binding energy levels that underlie mechanisms of growth modification and changes in overall crystal morphology. The combination of in situ AFM and molecular modeling provides new knowledge that will aid rationale design of therapeutic agents for inhibition of stone formation.

scholarly journals A new slick water system for hydraulic fracturing in tight reservoir to enhance imbibition oil recovery

2021 ◽  
Vol 303 ◽  
pp. 01001
Author(s):  
Yu Haiyang ◽  
Ji Wenjuan ◽  
Luo Cheng ◽  
Lu Junkai ◽  
Yan Fei ◽  
...  
Keyword(s):  
Contact Angle ◽  
Interfacial Tension ◽  
Hydraulic Fracturing ◽  
Oil Recovery ◽  
Water System ◽  
Natural Fracture ◽  
Fracturing Fluid ◽  
The Core ◽  
Ultralow Permeability

In order to give full play to the role of imbibition of capillary force and enhance oil recovery of ultralow permeability sandstone reservoir after hydraulic fracturing, the mixed water fracture technology based on functional slick water is described and successfully applied to several wells in oilfield. The core of the technology is determination of influence factors of imbibition oil recovery, the development of new functional slick water system and optimization of volume fracturing parameters. The imbibition results show that it is significant effect of interfacial tension, wetting on imbibition oil recovery. The interfacial tension decreases by an order of magnitude, the imbibition oil recovery reduces by more than 10%. The imbibition oil recovery increases with the contact angle decreasing. The emulsifying ability has no obvious effect on imbibition oil recovery. The functional slick water system considering imbibition is developed based on the solution rheology and polymer chemistry. The system has introduced the active group and temperature resistant group into the polymer molecules. The molecular weight is controlled in 1.5 million. The viscosity is greater than 2mPa·s after shearing 2h under 170s-1 and 100℃. The interfacial tension could decrease to 10-2mN/m. The contact angle decreased from 58° to 22° and the core damage rate is less than 12%. The imbibition oil recovery could reach to 43%. The fracturing process includes slick water stage and linear gel stage. 10% 100 mesh ceramists and 8% temporary plugging agents are carried into the formation by functional slick water. 40-70 mesh ceramists are carried by linear gel. The liquid volume ratio is about 4:1 and the displacement is controlled at 10-12m3/min. The sand content and fracturing fluid volumes of single stage are 80m3 and 2500 m3 respectively. Compared with conventional fracturing, due to imbibition oil recovery, there is only 25% of the fracturing fluid flowback rate when the crude oil flew out. When the oil well is in normal production, about 50% of the fracturing fluid is not returned. It is useful to maintain the formation energy and slow down the production decline. The average cumulative production of vertical wells is greater than 2800t, and the effective period is more than 2 years. This technology overcoming the problem of high horizontal stress difference and lack of natural fracture has been successfully applied in Jidong Oilfield ultralow permeability reservoir. The successful application of this technology not only helps to promote the effective use of ultralow permeability reservoirs, but also helps to further clarify the role of imbibition recovery, energy storage and oil-water replacement mechanism.

Predicting Hydraulic Fracturing in a Carbonate Gas Reservoir in Abu Dhabi Using 1D Mechanical Earth Model: Uncertainty and Constraints

2015 ◽  
Author(s):  
Manhal Sirat ◽  
Mujahed Ahmed ◽  
Xing Zhang
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Natural Fracture ◽  
Abu Dhabi ◽  
Hydraulic Fractures ◽  
Gas Reservoir ◽  
In Situ Stresses ◽  
Tight Carbonate ◽  
Different Depths

Abstract In-situ stress state plays an important role in controlling fracture growth and containment in hydraulic fracturing managements. It is evident that the mechanical properties, existing stress regime and the natural fracture network of its reservoir rocks and the surrounding formations mainly control the geometry, size and containments of produced hydraulic fractures. Furthermore, the three principal in situ stresses' axes swap directions and magnitudes at different depths giving rise to identifying different mechanical bedrocks with corresponding stress regimes at different depths. Hence predicting the hydro-fractures can be theoretically achieved once all the above data are available. This is particularly difficult in unconventional and tight carbonate reservoirs, where heterogeneity and highly stress variation, in terms of magnitude and orientation, are expected. To optimize the field development plan (FDP) of a tight carbonate gas reservoir in Abu Dhabi, 1D Mechanical Earth Models (MEMs), involving generating the three principal in-situ stresses' profiles and mechanical property characterization with depth, have been constructed for four vertical wells. The results reveal the swap of stress magnitudes at different mechanical layers, which controls the dimension and orientation of the produced hydro-fractures. Predicted containment of the Hydro-fractures within the specific zones is likely with inevitable high uncertainty when the stress contrast between Sv, SHmax with Shmin respectively as well as Young's modulus and Poisson's Ratio variations cannot be estimated accurately. The uncertainty associated with this analysis is mainly related to the lacking of the calibration of the stress profiles of the 1D MEMs with minifrac and/or XLOT data, and both mechanical and elastic properties with rock mechanic testing results. This study investigates the uncertainty in predicting hydraulic fracture containment due to lacking such calibration, which highlights that a complete suite of data, including calibration of 1D MEMs, is crucial in hydraulic fracture treatment.

scholarly journals Treatment of Metastatic Disease through Natural Killer Cell Modulation by Infected Cell Vaccines

Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 434
Author(s):  
Seyedeh Raheleh Niavarani ◽  
Christine Lawson ◽  
Lee-Hwa Tai
Keyword(s):  
Infected Cell ◽  
Natural Killer ◽  
Tumor Antigens ◽  
Critical Role ◽  
Killer Cell ◽  
Oncolytic Viruses ◽  
Cell Vaccine ◽  
Tumor Killing

Oncolytic viruses (OVs) are a form of immunotherapy that release tumor antigens in the context of highly immunogenic viral signals following tumor-targeted infection and destruction. Emerging preclinical and clinical evidence suggests that this in situ vaccine effect is critical for successful viro-immunotherapy. In this review, we discuss the application of OV as an infected cell vaccine (ICV) as one method of enhancing the potency and breadth of anti-tumoral immunity. We focus on understanding and manipulating the critical role of natural killer (NK) cells and their interactions with other immune cells to promote a clinical outcome. With a synergistic tumor killing and immune activating mechanism, ICVs represent a valuable new addition to the cancer fighting toolbox with the potential to treat malignant disease.

scholarly journals Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips

2017 ◽  
Vol 8 ◽  
pp. 2389-2395 ◽  
Author(s):  
Sumit Tewari ◽  
Koen M Bastiaans ◽  
Milan P Allan ◽  
Jan M van Ruitenbeek
Keyword(s):  
Atomic Structure ◽  
Scanning Tunneling Microscope ◽  
Critical Role ◽  
Atomic Layer ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
Stm Tips

Scanning tunneling microscopes (STM) are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.

scholarly journals Discrete Element Simulation of Interaction between Hydraulic Fracturing and a Single Natural Fracture

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 76
Author(s):  
Basirat ◽  
Goshtasbi ◽  
Ahmadi
Keyword(s):  
Hydraulic Fracturing ◽  
Fractured Reservoirs ◽  
Critical Role ◽  
Injection Pressure ◽  
Discrete Element ◽  
Natural Fracture ◽  
Effective Parameters ◽  
Fracture Geometry ◽  
Interaction Mode ◽  
Element Simulation

Hydraulic fracturing (HF) treatment is performed to enhance the productivity in the fractured reservoirs. During this process, the interaction between HF and natural fracture (NF) plays a critical role by making it possible to predict fracture geometry and reservoir production. In this paper, interaction modes between HF and NF are simulated using the discrete element method (DEM) and effective parameters on the interaction mechanisms are investigated. The numerical results also are compared with different analytical methods and experimental results. The results showed that HF generally tends to cross the NF at an angle of more than 45° and a moderate differential stress (greater than 5 MPa), and the opening mode is dominated at an angle of fewer than 45°. Two effects of changing in the interaction mode and NF opening were also found by changing the strength parameters of NF. Interaction mode was changed by increasing the friction coefficient, while by increasing the cohesion of NF it was less opened under a constant injection pressure.

scholarly journals In situ FTIR study of CO2 reduction on inorganic analogues of carbon monoxide dehydrogenase

2021 ◽  
Author(s):  
Ji-Eun Lee ◽  
Akira Yamaguchi ◽  
Hideshi Ooka ◽  
Tomohiro Kazami ◽  
Masahiro Miyauchi ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Critical Role ◽  
Co2 Reduction ◽  
Carbon Monoxide Dehydrogenase ◽  
In Situ Ftir ◽  
Ftir Study ◽  
Ir Study

In situ electrochemical IR study of the CO2 reduction by inorganic analogues of carbon monoxide dehydrogenase (CODH) reveals the critical role of Ni in the activity and selectivity of Fe sulfides for CO2 reduction.

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