Stress sensitivity of tight reservoirs and its effect on oil saturation: A case study of Lower Cretaceous tight clastic reservoirs in the Hailar Basin, Northeast China

New insights into spontaneous imbibition in tight oil sandstones with NMR

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ese3.817

Accurate characterization of full pore size distribution of tight sandstones by low‐temperature nitrogen gas adsorption and high‐pressure mercury intrusion combination method

Comprehensive characterization of pore and throat system for tight sandstone reservoirs and associated permeability determination method using SEM, rate-controlled mercury and high pressure mercury

The cost-effective fabrication of lightweight, safe, and solid-state supercapacitors with excellent performance, such as high energy and power densities and long cycle life, has recently become a critical issue in next-generation energy storage systems. As a result, current research efforts are focused on developing high-performance advanced electrode materials with high capacitance and outstanding stability, and solid electrolytes that provide flexibility and safety. Herein, the Marsh clay (peat soil) derived silica doped high yield and porous graphitic carbon (MCC) produced by simple pyrolysis and PVA/KOH polymer gel electrolyte are used as innovative components of the all-solid-state symmetric supercapacitor. Various characterizations were used to study the phase, microstructural, thermal, morphological, porosity, surface area, and compositional examination of the materials. An all-solid-state symmetric supercapacitor device based on the MCC and PVA/KOH gel electrolyte is fabricated. The developed supercapacitor device delivers a maximum specific capacitance of 160 F/g (at a scan rate of 10 mV/s) and exhibits a high energy density of ~18 Wh/kg at a power density of ~312 W/kg, and displays low resistance and good cycling stability. Overall, the developed all-solid-state symmetric supercapacitor with the novel MCC and PVA/KOH gel electrolyte represents the potential for high-performance supercapacitors. • March clay (organic carbon-containing biomass) derived highly graphitic carbon with high yield. • The introduction of silica (SiO 2 ) improves the graphitic nature of biomass-derived carbon material. • Development of all-solid-state symmetric supercapacitor with PVA/KOH gel polymer electrolyte • The symmetric supercapacitor device delivers a high specific capacitance of 160 F/g (at a scan rate of 10 mV/s) and retains high cyclic stability. • Symmetrical supercapacitor showed an energy density of 18 Wh/kg at a power density of 312 W/kg. 

Peat soil-derived silica doped porous graphitic carbon with high yield for high-performance all-solid-state symmetric supercapacitors

Experimental study on the oil-water relative permeability relationship for tight sandstone considering the nonlinear seepage characteristics

Fracturing is a fundamental technique for enhancing oil recovery of tight sandstone reservoir. The pores in tight reservoirs generally have small radii and generate tremendous capillary force; accordingly, the imbibition effect can significantly affect retention and absorption of the fracturing fluid. In this study, the imbibition behaviors of the fracturing fluid were experimentally investigated, and the effects of interfacial tension, (IFT) permeability, oil viscosity, and the salinity of the imbibition fluid were determined. In addition, combining with nuclear magnetic resonance (NMR)-based core analysis, fluid distribution, and the related variations in imbibition and displacement processes were analyzed. Finally, some key influencing factors of imbibition of the residual fracturing fluid, the difference and correlation between imbibition and displacement, as well as the contribution of imbibition to displacement were explored so as to provide optimization suggestions for guiding the application of oil-displacing fracturing fluid in exploration. Results show that imbibition recovery increased with time, but the imbibition rate gradually dropped. There exists an optimal interfacial tension that corresponds to maximum imbibition recovery. In addition, imbibition recovery increased as permeability and salinity increases and oil viscosity decreases. Furthermore, it was found that extracted oil from the movable pore throat space was almost equal to that from the irreducible pore throat space during imbibition and their contribution in the irreducible pore throat space was greater than in the movable pore throat space in the displacement process. Hence, imbibition plays a more important role during the displacement process in the reservoirs with finer porous structure than previously thought.

Experimental Simulation on Imbibition of the Residual Fracturing Fluid in Tight Sandstone Reservoirs

Hydraulic fracturing is one of the key technologies to enhance the oil recovery from tight sandstone reservoirs. The study on the behavior of imbibition for tight sandstone reservoir is of great significance to increase oil production after fracturing. In this paper, nuclear magnetic resonance (NMR) and high-pressure mercury injection were implemented on the samples taken from the Yanchang Formation of the Ordos Basin. The NMR T2 curves of the core at the state of 100% water saturated were converted to pore-throat radius distribution curves. On this basis, the experiments of imbibition and displacement were conducted and the changes of fluid distribution, imbibition quantity, and imbibition rate with different scale pores and different imbibition times were analyzed. Moreover, the results of imbibition and displacement were compared to assess the distribution of the recoverable and remaining oil under two exploitation modes and the contribution of imbibition made to displacement in pores at different scal...

Shuaishi Fu

Papers

Accurate characterization of full pore size distribution of tight sandstones by low‐temperature nitrogen gas adsorption and high‐pressure mercury intrusion combination method

Experimental study on the oil-water relative permeability relationship for tight sandstone considering the nonlinear seepage characteristics

Experimental Simulation on Imbibition of the Residual Fracturing Fluid in Tight Sandstone Reservoirs

Study of the Imbibition Behavior of Hydrophilic Tight Sandstone Reservoirs Based on Nuclear Magnetic Resonance

The Experimental Study on the Flooding Regularities of Various CO2 Flooding Modes Implemented on Ultralow Permeability Cores