Hydraulic fracturing and acidification are among the most commonly used methods for stimulating the tight oil reservoirs and improving oil recovery. Therefore, examining the effects of water immersion and acidification on tight oil reservoirs is important for oilfield development plans. Core flooding testing, which analyzes the influence of core permeability variations before and after acid injection on the reservoir quality, is the conventional research method; however, it is difficult to observe the changes in minerals and pores caused by acidulation and water immersion in situ . In this study, we conduct field-emission scanning electron microscopy (FE-SEM), MAPS, the quantitative evaluation of minerals through scanning electronic microscopy (QEM-SCAN), and describe the types of pores in tight sandstone. Further, the effects of water immersion and acidification on pores in tight sandstone were studied. The results indicate that: (1) intergranular pores, intragranular dissolution pores, clay mineral intercrystalline pores, and micro-cracks were developed in the Gaotaizi tight sandstone in Songliao Basin, with the intergranular pores observed to be dominant; (2) the hydration of clay minerals induced by water injection caused plugging of pores at the nanometer– micrometer scale, and plane porosity is slightly reduced (˜0.86%); (3) acidification resulted in the dissolution of carbonate minerals, increasing the porosity of the reservoir, therefore, the increase in porosity is influenced by the carbonate mineral content. We recommend that future studies should investigate the content, type, and distribution of carbonate minerals in the operation area. During the process of reservoir stimulation, such as acidification and CO 2 injection- and-production, the influence of carbonate minerals dissolution on oil production should be considered.
A strain A2 is separated from the oil /water sample in Shengli Oilfield,which can produce surfactant by means of hydrocarbons at high temperature.It belongs to Petrobacter.The experimental results show that,the degradation rate of the strain to Gudao crude oil and Gan 17 crude oil can reach to 39.81% and 22.60% separately;its viscosity reducing ratio to Gudao crude oil and Gan 17 crude oil can reach to 37.95% and 25.00% separately;it can make the solidifying point of Gudao crude oil and Gan 17 crude oil decrease 2.5 ℃.After the surface of glass,quartz and limestone is treated by the strain liquid,their contanct angle can decrease by 72%,68% and 24% separately.Under the condition of Ng3 oil reservoir,the microbial flooding of the strain can enhance the recovery factor by 9.3%.Field test shows that,in the microbial flooding test area,the water cut decreases by 2.1%,the cumulative oil yield increases by 0.36×104 t,and the recovery factor enhances by 0.21%.
Constructing Mott–Schottky electrocatalysts is a proof-of-concept strategy to design efficient water splitting catalysts. Here, we focus on the basics of Mott–Schottky catalysts and the fundamental understanding of their catalytic mechanisms.
Deep fluid activity is widespread in large oil-gas basins around the world. Deep fluids, as the links between internal and external factors of a basin, run in the way of organic-inorganic interactions through the oil-gas formation and aggregation. Herein, the identification characteristics of deep fluids in sedimentary basins as well as their influence on oil-gas reservoir formation and geothermal resource are summarized. The deep fluids of sedimentary basins are identified from three aspects, including mineral composition, fluid inclusions, and geochemical characteristics. The effects of deep fluid activities on oil-gas reservoir formation are manifested in two key aspects of matter and energy. As for the matter effects, deep fluids can improve the primary productivity of sedimentary basins and carry abundant inorganic hydrogen, which contributes to improving the hydrocarbon productivity through hydrogenation. As for the energy effects, the heat energy of deep fluids can promote the mature evolution from organic matter to oil and gas. During this process, the heating of deep fluids will cause the oil-generation window depth of the hydrocarbon source rocks to become thinner, and it will also generate very high pressure, which will promote the discharge of abundant hydrocarbons formed by the hydrocarbon source rocks. Furthermore, deep fluids can directly form volcanic rock oil-gas reservoirs. And another manifestation of deep fluid energy is geothermal. And the thermal energy of deep fluids can directly form hot dry rocks, which is the most important existing form of geothermal resources. The geological exploration of hot dry rocks should be supported by further geochemical and geophysical research.
Abstract Influenced by sedimentary and tectonic factors, the accumulation conditions and models of Permian reservoirs in southern Huanghua Depression are unclear. Based on geochemical data of source rocks and petrophysical property data of reservoirs, by means of seismic interpretation, geochemical testing and profile analysis of typical reservoirs, the accumulation conditions are clarified, and the accumulation model is put forward. The study show that the intensity of secondary hydrocanbon generation is a favorable condition for the formation of gas field. The thrust structural traps in Huanghua Depression were mainly formed in the Indosinian, and anticline traps were mainly developed in the Yanshanian and Himalayan. Several source-reservoir-cap assemblages were developed inside the buried hill. Strong tectonic activity created good migration paths for natural gas, and the matching of trap formation, tectonic activity and hydrocarbon expulsion is the key factor of the accumulation of gas. On this basis, the typical gas accumulation pattern is established.
This paper aims to study and analyze the attitude control problems of the rocket pitching channel during boosting phase. Firstly, a linearization control model was established for the pitching channel of a rocket based on the linear perturbation method. Secondly, a fuzzy sliding mode controller was designed for the pitching channel of a rocket projectile considering the constraint rudder deviation based on linear sliding surface, auxiliary system, and fuzzy control system. Finally, the Lyapunov stability theory was used to verify the stability of the designed control strategy, and the effectiveness of the control scheme was verified through digital simulation.
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