A probabilistic model of petroleum discovery

We discuss a petroleum discovery model that greatly simplifies the approach initiated by Barouch and Kaufman (1976) in which exploration is viewed as a sampling without replacement process, and the probability of discovery of a pool is proportional to its size. Calculations that formerly required lengthy Monte Carlo simulations have been reduced to compact formulas.     

An assessment of oil supply and its implications for future prices

This paper examines three issues related to both the U.S. and world oil supply: (1) the nature of the long-term, postpeak production profile for the U.S. and, by inference, other regions (the Hubbert curve is used as a “strawman” model); (2) implications on U.S. energy security of using a modified Hubbert-type conceptual model of prepeak production, testing the adequacy of Latin America to be the primary source of U.S. oil imports; and (3) the cyclic behavior of oil prices. it shows that U.S. production will exhibit a more attenuated decline than that simulated by the Hubbert curve and not decline to zero. it asserts that U.S. production is better predicted by past reserves than past production, but that this argument does not apply to nations that keep a much larger proportion of reserves in the ground. Such nations could considerably expand production without any growth in reserves. The paper concedes that the potential total production for these nations could be examined with a Hubbert curve model linked to reserves, but with great uncertainty. Such an uncertain optimistic forecast predicts that the cumulative production of Latin America could far exceed that of the United States. Nevertheless, a statistical model of oil prices since 1870 implies that real wellhead oil prices in the United States are on a long-term upward path, underlying a much more “noisy” cyclical pattern estimated to include 22- and 27-year cycles. The statistical model predicts a severe oil shock within a few years (of 1998) but also predicts that through 2030, real oil prices will not reach 1981 levels again. The paper examines U.S. and world trends in seismic exploration, drilling locations and depths, drilling costs, oil/gas reserves, oil/gas use rates, and oil demand. After taking these factors into consideration, it concludes that the statistical model of oil prices cannot be disputed, despite its lack of basis in economic theory.     

新疆油气资源开发前景展望

新疆主要沉积盆地有30多个,总面积90×104km2,油气资源十分丰富,油气资源量365×108t。虽然经过50多年油气勘探历程,已发现80多个油气田,但勘探潜力巨大。笔者从目前勘探形势,油气勘探阶段,资源转化率、形成大油气田地质条件及油气资源发展战略等方面进一步论述新疆是我国油气资源主要接替区。     

俄罗斯油气资源空间分布格局及可达性评估

俄罗斯地区油气资源储量十分丰富,未探明储量的地区也有巨大的资源应用前景。随着气候变化加剧,北极通航变为可能,俄罗斯也寄希望于通过北极航道,大力发展其能源贸易。本文将俄罗斯交通网络作为连接资源和港口的重点,采用空间统计方法刻化俄罗斯油气资源空间分布特征,并通过栅格成本距离法、加权平均旅行时间和区位优势潜力等方法量化各港口对油气资源的可达性,得出结论：① 油气资源集中分布在西西伯利亚平原,俄罗斯全域的港口可达性呈“西部高,中部低”的特征;② 俄罗斯东北地区港口的资源可达性普遍较差,西北地区港口资源可达性较好。综合考虑油气资源、地理位置和项目合作等方面,可重点建设萨别塔、摩尔曼斯克和符拉迪沃斯托克（海参崴）3个港口;③ 附近交通网络的布设密集度影响港口的资源可达性。随着气候变暖,冻土融化,加上中俄“冰上丝绸之路”倡议的逐步实施,未来远东地区港口的资源可达性可能有进一步提升的空间。     

An interpretation of the Nusselt-Rayleigh number relationship for convection in a spherical shell

Recent studies on the relationship between the Nusselt ( Nu ) and Rayleigh ( Ra ) numbers for base-heated convection in a spherical shell with a constant viscosity show that the power-law index is around 1/4, which is different from the value of 1/3 predicted by a simple boundary layer theory. We show that such a difference may be caused by the flow pattern due to the geometry. The flow pattern of the convection in a spherical shell at relatively low Ra , at least, less than 10⁶, is characterized by narrow upwelling and broad downwelling, which is similar to the opposite flow pattern of internally heated convection. Convection in the internally heated case predicts the power-law index of 1/4. We demonstrate this relationship based on the concept of 'local' Rayleigh ( Ra1 ) and Nusselt ( Nu1 ) numbers     

An analytical approach for the scattering of SH waves by a symmetrical V-shaped canyon: shallow case

Based on the application of the region-matching technique, an analytical approach is presented for the scattering of plane SH waves from a shallow symmetrical V-shaped canyon, and then a series solution is derived. The analysed region is divided into an enclosed and an open region by introducing a semi-circular auxiliary boundary. In each region, the displacement field can be expressed as infinite sum of appropriate wavefunctions satisfying partial boundary conditions, respectively. The unknown coefficients can be determined by enforcing the continuity conditions in connection with the Graf's addition formula. The frequency- and time-domain responses are both evaluated and displayed for several physical parameters. From graphical results, the effects of the canyon depth on surface ground motion are conspicuous. The proposed series solutions can serve as benchmark for numerical methods, in particular for those at much higher frequencies.     

Interhemispheric observations of field line resonance frequencies as a continuous function of ground latitude in the auroral zones

In the austral summer of 2006–2007, the 48th Japanese Antarctic Research Expedition (JARE-48) installed two unmanned low-power magnetometers to form a closely spaced magnetometer network in combination with the permanent sites at Japan's Syowa Station in Antarctica. To identify field line resonances (FLRs), gradient methods are applied to the data from three adjacent sites in Antarctica and data from conjugate points in Antarctica and Iceland. By analyzing the data from the Antarctic and Icelandic sites individually, the structure of FLRs with high coherence is clearly identified. However, by analyzing the data from closely spaced Antarctic sites, it is more difficult to identify the signature of FLRs because of the inclusion of multiple signals related to the local geomagnetic pulsations over a broad frequency range. The frequency and resonance width of FLRs are determined by applying the amplitude phase gradient method (APGM) to the data from Antarctic sites. This yields the eigenfrequency as a continuous function of ground latitudes in the area surrounding Syowa Station. The mass density in the equatorial region at the L of the auroral zones is estimated from the obtained FLR frequency by numerically solving the standing Alfvén wave equation. The mass density thus obtained is consistent with observational results from previous in situ measurements by spacecraft. The results of the present study demonstrate that data from geomagnetic conjugate points are helpful in identifying FLR in cases in which the magnetometers are too close to each other to enable identification. Once FLR is identified, APGM can be applied to the identified FLR, yielding the FLR frequency as a continuous function of ground latitudes. Therefore, the magnetospheric equatorial mass density is readily estimated with high spatial resolution.     

Understanding the spatial distribution and physical attributes of upland swamps in the Sydney Basin as a template for their conservation and management

Temperate Highland Peat Swamps on Sandstone (THPSS) and Coastal Upland Swamps in the Sydney Basin (CUSSB) are listed as endangered ecological communities under Australia's national and state legislation. They are threatened by a range of human and climate impacts. Across the region there are 3208 individual, valley-bottom, elongate-shaped, upland swamps that drain first- or second-order drainage lines and small catchment areas (mean?=?0.25?km²). They occur at a median distance of 57?km from the coast in areas with an average annual rainfall of 1505?mm/year and average annual temperature of 15°C. Those closer to the coast occur on elevations as low as 160?m a.s.l., and those further from the coast, on plateau country, occur up to 1172?m a.s.l. (median 634?m a.s.l.). The valleys that contain these swamps terminate downstream at a valley constriction or bedrock step, behind which alluvial materials have accumulated, and peat has formed to produce relatively steep swamps (median slope 6.2 per cent). Understanding the spatial distribution and physical attributes of these systems, and having the accompanying maps as a resource, is critical for development of sound, well-informed conservation, rehabilitation and monitoring programs, and for analysing the ecosystem services they provide.     

An assessment of land cover change as a source of information for conservation planning in the Vhembe Biosphere Reserve

Determining changes in land use/land cover (LULCC) can be used to assess and monitor habitat loss as one of the five global priority causes of biodiversity loss. In South Africa, two national land-cover (NLC) datasets have been developed from satellite imagery obtained in circa 1990 and 2013/2014. The Vhembe Biosphere Reserve (VBR), designated in 2009, is located in the north of the Limpopo Province in South Africa and has a surface area of 30,457 km². The aim of biosphere reserves is to provide a landscape-scale framework for conservation and sustainable development of an area. The area within a biosphere reserve is prioritised by designating it into one of three zones 1) Core, 2) Buffer, and 3) Transitional Zones. Two national parks and six provincial reserves (PAs) are the current and form part of the proposed updated core areas (pCAs) of the VBR. Intensity analyses was used to assess LULCC in the VBR. The pCAs cover 39.7% of the surface area of the VBR. The PAs cover 39.7% and only 15.8% of the surface area of the pCAs and VBR respectively. Based on the NLC 2013/2014 a majority of the VBR, pCAs and PAs consisted of indigenous vegetation dominated by Woodland/Open bush, Grassland, and Thicket/Dense bush. The extent of transformed land in the VBR declined from 1990 to 2013 by 1697.7 km². The total amount of change and mean annual change in the VBR was 53.1% and 2.31% respectively. The overexploitation of fuel wood by rural communities in rural areas of the VBR, was partly responsible for the targeted loss of Woodland/Open bush to Thicket/Dense bush and Grasslands. The unquantified presence of novel vegetation and alien invasive plants means that the NLC 1990 and 2013/2014 overestimates the quantity and distribution of the remaining indigenous vegetation in the VBR. In order to address this the distribution of alien and indigenous invasive plant species in the VBR needs to be determined and used to update future NLCs. Assuming a worse-case-scenario of all the coal deposits in the VBR, including the Kruger National Park, being mined it would amount to 24.7% of the surface area of the VBR. Only 6.8% of the area of all the coal deposits in the VBR was transformed with 93.2% currently remaining untransformed. It is recommended that transformation of indigenous vegetation to one of the seven transformed land cover categories and more specifically from coal mining should be restricted to the VBR's Transition Zones.     

中国发展中国家地位的论证——基于190个经济体多维发展水平分类的实证分析

科学判断一个国家在全球体系中的地位是制定外交政策的基础。目前中国的发展中国家地位遭到了西方国家的质疑,国内学者从国别比较等视角出发论证了中国的发展中国家地位,但缺乏从全球尺度分类视角的回应。论文基于多面体法、洛伦兹曲线分类法等方法,从经济、社会、环境、治理等方面构建经济体的多维发展水平分类指标体系和测度模型,将全球190个经济体划分成发达经济体Ⅰ~Ⅲ型、发展中经济体Ⅰ~Ⅴ型和过渡型经济体共9种类型,并探讨了不同类型经济体的发展水平特征、中国在全球经济体分类体系中的地位等问题。研究发现：① 不同类型经济体在经济、社会、环境、治理等分维度发展水平方面具有显著的差异性。② 发达经济体各维度发展水平排名普遍较高,总体呈现“并驾齐驱”特征;过渡型经济体在很多维度的发展指标与发达经济体Ⅲ型接近,多数经济体处于逐渐向发达经济体过渡的发展阶段;发展中经济体在分维度发展水平方面存在显著的结构性差异。③ 中国属于发展中经济体Ⅰ型类别,在全球190个经济体中排在第64位,在139个发展中经济体中排在第13位。④ 中国在全球经济体多维发展水平排序、各维度发展水平差异等方面具备发展中国家的普遍特征。该研究洛伦兹曲线分类法等方法的应用可丰富区域发展分类理论,相关结论可为回击西方国家对中国发展中国家地位的质疑提供借鉴。