查看更多>>摘要：Hydraulic fracturing is an important technique for reservoir stimulation. However, the productivity of vertical wells with horizontal fractures in shallow formations for quick reservoir evaluation has been under-researched. In this study, we approximate the actual flow by four regimes: 1) radial flow in far field; 2) vertical linear flow in near fracture area; 3) radial flow in near fracture area; 4) radial flow inside the fracture. Then we established an analytical productivity model for vertical wells with multiple horizontal fractures in shallow formations. For one fracture, the result deviation of our model is less than 5.3% from the classical method. For four fractures, our result is within 9% of deviation compared with CMG numerical simulation software. This model can be used to optimise parameters of horizontal fractures.
查看更多>>摘要：This work presents the use of rolling-ball viscometer to measure viscosity reduction of two dead oil samples injected with CO2 at a temperature of 168°F and a pressure range of 1,114.7 psi-3,514.7 psi. First, a new digital control unit was designed to replace the analogue unit. Afterwards, viscometer was calibrated with Cannon S-6 and S-60 viscosity standards. Next, validation was conducted by measuring the viscosity of n-decane at a temperature range of 77°F-266°F and a pressure range of 514.7 psi-2,014.7 psi. Next step was the investigation of CO2 effect in reducing n-decane viscosity at 130°F-266°F temperature range and 1,014.7 psi-2,014.7 psi pressure range. Results showed significantly reduced viscosities of the CO2 mixture compared to n-decane viscosities, especially at lower temperatures. Afterwards, viscosity of two distinct crude samples was measured at 168°F and 14.7 psi-3,514.7 psi pressure interval. Next, CO2 was injected to respective oil samples and system viscosity was measured at the same temperature and at pressures between 1,114.7 psi and 3,514.7 psi.
查看更多>>摘要：In carbon capture and sequestration (CCS), geological sequestration of carbon dioxide (CO2) in deep saline aquifers with porous and permeable rocks is one of the most feasible among various solutions to sequester CO2. Here, the TOUGH2 numerical simulator was validated with the analytical model developed predicting the CO2 behaviour in confined saline aquifers. The sensitivity of the numerical model was examined by changing the model of fluid relative permeability (RP) and capillary pressure (CP) functions. Corey's RP functions and Van Genuchten's CP function is most effective to capture the gas saturation (SG) well. The effect of CO2 injection, well orientation, and its length in a simplified saline aquifer model are also demonstrated. This study reveals that the horizontal well configuration is most acceptable. For the same injection well length (at 100 m), 22% drop in the pressure rise is computed in horizontal well as compared to its vertical counterpart.
查看更多>>摘要：Since hydraulic fracturing fluid plays a significant role in the soaking process, it is interesting to present a study of the imbibition effect by slickwater, brine and guar gum. In this paper, we conducted an experimental study of the imbibition effect on recovering the tight Mahu field, which are the largest discovered conglomerate reservoirs. The recovery performance by different imbibition fluids was compared. Nuclear magnetic resonance (NMR) technique was used to understand what type of pore scale contributes mostly to the imbibition recovery process. Laboratory results indicated that the lowest interfacial tension in some sense is adverse to spontaneous imbibition. The imbibition rate with the largest interfacial tension is the highest. When the bond number falls in a value where both capillary forces and gravity drainage play a role in the recovering process, the oil recovery factor is significant in this case. The oil recovery factor by slickwater imbibition is 40.76%, which is much higher than brine and guar gum. It is observed that the slickwater displacement still recovered additional oil after the imbibition process.
查看更多>>摘要：The large deformation and serious failure of the anchor bolt (cable) of a thin coal seam island coal face retrieval mining roadway is a very difficult technical problem to solve. This article is based on the background of the Jizhong Energy Company Handan Mining Group Guo Erzhuang mine 22204 face mining. Through research, theoretical analysis, numerical simulation and experimental methods that revealed the characteristics of the perimeter rock of the roadway and the destruction mechanism, the composite support scheme of 'anchor + anchor cable + lining' was designed to calculate the reliability of the ultimate bearing capacity of the scheme. The simulation analysis of the design with numerical simulation software was used to verify the rationality of the support scheme. Finally, the composite support was successfully applied in the Guo Erzhuang mine. The onsite monitoring results showed a 64% reduction in the roof subsidence and a 70% reduction in the deformation of two gangway. The support scheme effectively controlled the convergent deformation of the retrieval roadway and achieved good industrial testing expectations. The results of the research could provide a reference for the control technology of a thin coal seam island coal face retrieval roadway under similar geological conditions.
查看更多>>摘要：Here, bamboo types found in India such as Dendrocalamus asper, Pseudosasa japonica, Dendrocalamus gfganteus, Sinarundinaria falcata, and Bambnsa vulgaris are considered for the thermochemical conversion process. Primarily, these bamboos are converted to bio-oil by the pyrolysis process and found that Bambusa vulgaris yields more bio-oil than all other bamboos. Later, the bio-oils generated from bamboos are converted to biodiesels through the transesterification process. The properties such as relative density, acid number, kinematic viscosity, cetane number, flash point, cloud point, pour point, ash content, carbon residues, and higher heating value of all biodiesels are done. It is found that biodiesel generated from Bambusa vulgaris has the property values neared to standard biodiesel, so the properties of different blends of Bambusa vulgaris biodiesel with petro-diesel are also found. Here, the result shows that the blend BV15 is suitable for CI engines as it keeps all the property values of good biodiesel.
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