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111.
112.
This study investigates petrophysical and acoustic properties of experimentally compacted reconstituted samples of seal sequences from the southwestern Barents Sea. The aggregates were collected from drill cuttings of mudstone and shale formations of two exploration wells, 7220/10-1 (Salina discovery) and 7122/7-3 (Goliat field). The washed and freeze-dried samples were characterized for grain size distributions, geochemical analyses, and mineralogical compositions. A total of 25 compaction tests (12 dry and 13 brine-saturated) were performed with a maximum effective vertical stress of 50 MPa. The laboratory measurements demonstrated that petrophysical and acoustic properties of argillaceous sediments can change within a sedimentary basin and even within a given formation. The results show that the collected aggregates from Goliat field are compacted more compared to Salina discovery. The maximum and minimum compaction are measured in samples collected from Snadd and Fuglen formations, respectively. The final porosity of brine-saturated specimens varies between 5% and 22%. The ultrasonic velocity measurements depict that samples with the same porosity values can have a broad range of velocity values. The resulting compaction trends in this study were compared to published compaction curves for synthetic mixtures of quartz and clay. All compaction trends show higher porosity reduction than the silt fraction with 100% quartz. Comparison of experimental compaction result of each mudstone and shale aggregate with its corresponding acquired well log data helps to delineate the burial history and exhumation in the study area. A net exhumation of 950 m and 800 m is estimated at Salina and Goliat wells, respectively. The outcomes of this study can provide insights for hydrocarbon prospect discovery in a pre-mature sedimentary basin in terms of exploration and production, and also for geological CO2 storage sites. The experimental results may provide information for well log and seismic interpretation, basin modeling and seal integrity of investigated horizons. 相似文献
113.
What factors control mechanical erosion rates? 总被引:1,自引:0,他引:1
C. G. A. Harrison 《International Journal of Earth Sciences》2000,88(4):752-763
Mechanical erosion rates are important factors in understanding how continents evolve. Mechanical erosion is much faster
than chemical erosion, especially for highly elevated regions of the Earth's surface. It is a principal way in which mountain
ranges are removed, exposing deep metamorphic roots, which comprise much of the older portions of the continental masses.
In addition, there has to be a long-term balance between erosion and mountain building. A new data set allows us to explore
in greater detail some of the many factors which control mechanical erosion rates. The most important factors are some expression
of the average slope of a drainage basin, some measurement of the amount of water available for erosion, some environmental
measurements, and also a measurement of basin length, for which we have no good explanation. The estimate of global mechanical
erosion rate obtained here is considerably lower than those obtained by some other workers, some of whom have concentrated
on the fact that smaller river basins tend to get eroded faster than larger basins, and it is mainly smaller basins which
have not been measured and which are therefore not allowed for by simple arithmetic averaging of observed erosion rates. It
is shown here that although smaller basins are eroded faster, this is mainly because they are steeper than larger basins.
We also show that extrapolation of current data to smaller basins does not work because the observed continental area which
is draining to the ocean cannot be attained by the simplest extrapolation scheme.
Received: 23 October 1998 / Accepted: 29 June 1999 相似文献
114.
WANG Xiaoqiong XU Jianguo ZHAO Chenxu LIU Tongyuan GE Hongkui SHEN Yinghao WU Shan YU Jiayao HUANG Rongyan 《中国地震研究》2020,34(2):167-186
The premise of hydraulic fracturing is to have an accurate and detailed understanding of the rock mechanical properties and fracture propagation law of shale reservoirs. In this paper, a comprehensive evaluation of the mechanical properties of the shale oil reservoir in the south of Songliao Basin is carried out. Based on the experiments and the in-situ stress analysis, the fracture propagation law of three types of shale reservoirs is obtained, and the suggestions for fracturing are put forward. The results have shown that the fracture propagation of pure shale and low mature reservoir is easy to open along the bedding plane under compression loading, which is greatly influenced by the bedding. Sand-bearing shale is slightly better, the fractures of which are not easy to open along the bedding plane. The mechanical experimental results show that all the samples have the characteristics of low compressive strength, low Young''s modulus and strong anisotropy, indicating that the shale oil reservoir is certain plastic, which is related to its high clay mineral content and controlled by the bedding development. Compared with pure shale and low mature shale, the sand-bearing shale has less clay content and less developed bedding, which maybe the main reason for its slightly better brittleness. Overall, the expansion of hydraulic fracture is controlled by in-situ stress and bedding. Because of the development of bedding, it is easy to form horizontal fractures. Thus it is not suitable for horizontal well fracturing. Because of the high content of clay minerals, the applicability of conventional slick hydraulic fracturing fluid is poor. It is suggested to use vertical well or directional well to carry out volume fracturing. In this way, the effect of bedding can be effectively used to open and connect the bedding and form a larger fracture network. 相似文献
115.
116.
ZHOU Bo GE Hongkui ZHOU Wei WANG Jianbo HAO Hongyong WANG Xiaoqiong LIU Pengyu 《中国地震研究》2020,34(3):430-451
In recent years, with the success of exploration and development of conglomerate reservoirs in Mahu Depression, Junggar Basin, China, it is urgent to study the mechanical properties and its influencing factors of conglomerate which is considered as a new oil and gas reservoir. Based on the investigations of petrologic characteristics, heterogeneity and mechanical properties of conglomerate in Baikouquan formation, the content and geometric characteristics of gravel in conglomerate, the main factors in heterogeneity and the mechanical behavior in the triaxial compression experiment of conglomerate are analyzed in this paper. The results show that the size and content of gravel in conglomerate varies greatly, and conglomerate has strong heterogeneity under the influence of gravel content and size. An analysis of mechanical properties of conglomerate shows that conglomerate is characterized by plasticity. Besides, the sphericity is negatively correlated to the gravel content, while the heterogeneity increases with the increase of conglomerate plasticity. Due to the existence of heterogeneous gravel, local stress may concentrate in conglomerate when the stress is loaded. Consequently, a large number of micro-cracks appear at the edge of gravel, demonstrating the strong plasticity of conglomerate. This paper is of referential significance to the study of rock mechanical properties and the evaluation of engineering properties in conglomerate development. 相似文献
117.
《地学前缘(英文版)》2020,11(6):1901-1913
The significance of source rocks for oil and gas accumulation has been indisputably acknowledged. Moreover, it has been gradually realized that there is difference between hydrocarbon generation capacity and hydrocarbon expulsion capacity, and this has prompted research on hydrocarbon expulsion efficiency. However, these studies dominantly highlight the results of hydrocarbon expulsion, and investigation into the corresponding process and mechanism is primarily from a macroscopic perspective. Despite its wide acceptance as the most direct hydrocarbon expulsion mode, hydrocarbon expulsion through micro-fractures is still not sufficiently understood. Therefore, this study obtains observations and performs experiments on two types of source rocks (mudstones and shales) of the Chang 7 oil group of the Yanchang Formation in Ordos Basin, China. Microscopy reveals that organic matter is non-uniformly distributed in both types of source rocks. Specifically, mudstones are characterized by a cluster-like organic matter distribution, whereas shales are characterized by a layered organic matter distribution. Thermal evolution simulation experiments demonstrate that the hydrocarbon generation process is accompanied by the emergence of micro-fractures, which are favorable for hydrocarbon expulsion. Moreover, based on the theories of rock physics and fracture mechanics, this study establishes micro-fracture development models for both types of source rocks, associated with the calculation of the fracture pressure that is needed for the initiation of fracture development. Furthermore, the relationship between the fluid pressure, fracture pressure, and micro-fracture expansion length during micro-fracture development is quantitatively explored, which helps identify the micro-fracture expansion length. The results indicate that the development of micro-fractures is commonly impacted by the morphology and distribution pattern of the organic matter as well as the mechanical properties of the source rocks. The micro-fractures in turn further affect the hydrocarbon expulsion capacity of the source rocks. The results of this study are expected to provide theoretical and practical guidance for the exploration and exploitation of tight oil and shale oil. 相似文献
118.
许多重要的软土工程譬如基坑、路基工程在破坏后需要快速修复,磷酸镁水泥的出现很好地满足了这一现代建设的要求,但不同地区软土的有机质含量不同,而有机质的含量对固化土的性质有着重要影响。为了研究磷酸镁水泥加固不同有机质含量软土的加固规律,本文通过向烘干后的软土中添加腐殖酸,人为制备不同有机质含量的土样,并取相同条件下PO水泥加固软土作对比,通过相关力学试验得到以下规律:两种水泥在加固不同含量有机质软土的过程中,加固效果都会随着有机质含量的升高而逐渐降低;磷酸镁水泥在快速修复和凝结方面明显优于PO水泥,但磷酸镁水泥中长期加固有机质软土的效果却不及PO水泥。同时利用SEM试验对得到的规律进行了解释并分析其微结构演化特征。该研究成果独到地分析了有机质含量变化对磷酸镁水泥加固效果的影响,证明了磷酸镁水泥可以应用于软土的抢修工程建设中,对加固软土工程具有指导和借鉴意义。 相似文献
119.
考虑地应力的洞室围岩块体稳定性分析的理论与实践 总被引:6,自引:0,他引:6
地下洞室围岩的稳定性状态,在很大程度上受围岩应力状态决定,以前的地下洞室岩稳定性分析,一般仅考虑在自重作用下的稳定性状态。而吻略了地应力地围地应力对围岩稳定性的影响,所得结论往往偏于保守。 相似文献
120.