Comparison of Two Probability Distributions Used to Model Sizes of Undiscovered Oil and Gas Accumulations: Does the Tail Wag the Assessment?     

Emil D. Attanasi  Ronald R. Charpentier 《Mathematical Geology》2002,34(6):767-777

Undiscovered oil and gas assessments are commonly reported as aggregate estimates of hydrocarbon volumes. Potential commercial value and discovery costs are, however, determined by accumulation size, so engineers, economists, decision makers, and sometimes policy analysts are most interested in projected discovery sizes. The lognormal and Pareto distributions have been used to model exploration target sizes. This note contrasts the outcomes of applying these alternative distributions to the play level assessments of the U.S. Geological Survey's 1995 National Oil and Gas Assessment. Using the same numbers of undiscovered accumulations and the same minimum, medium, and maximum size estimates, substitution of the shifted truncated lognormal distribution for the shifted truncated Pareto distribution reduced assessed undiscovered oil by 16% and gas by 15%. Nearly all of the volume differences resulted because the lognormal had fewer larger fields relative to the Pareto. The lognormal also resulted in a smaller number of small fields relative to the Pareto. For the Permian Basin case study presented here, reserve addition costs were 20% higher with the lognormal size assumption.  相似文献   

牙轮钻头振动规律分析          下载免费PDF全文

张艺伟  杨海波  赵德云  杨跃波 《探矿工程》2002,(4):29-30

通过大量的实验数据，对三牙轮钻头在井底振动时干扰力的幅值和频率进行了全面而细致的分析，摸索出了其在井底的振动规律，提高了井下钻具动力学分析的准确度，可在一定程度上减少钻具失效、节约钻井成本。  相似文献   

Mixing Methodologies in Seismic Hazard Assessment via a Logic Tree Procedure: An Application for Eastern Spain     

J. J. Giner  S. Molina  J. Delgado  P. Jáuregui 《Natural Hazards》2002,25(1):59-81

This study provides a procedure for assessing seismic hazardand uncertainties in regions that are characterised by a large non-instrumental earthquakedatabase and a seismic and tectonic behaviour which doesn't allow an evident seismic zonation.This procedure is a synthesis of the non-zoning or non-parametric methodology (using extremevalues distribution functions as proposed by Epstein and Lomnitz, 1966) and the zoning orparametric methodology (using the theorem of total probability as proposed by Cornell, 1968)via a logic tree procedure taking into consideration the advantages offered by each of these.Taking the area which we shall describe as the east coast of Spain and surrounding inland areas,an application was made and a specific logic tree was developed in order to solve the problems anduncertainties related to the evaluation of the seismic hazard using both methodologies. The use of thelogic tree allowed the systematisation of a large number of solutions obtained. A number of relevantresults were obtained which show that in some cases there are great differences in the seismichazard results provided by the non-zoning and the zoning methodologies. In these cases, mean value andstandard deviation of the obtained results provide an intermediate solution to the over-conservativeestimation provided by the non-zoning methodology and the lowest results provided by the zoningmethodology. In other cases results provided by both methodologies are significantly closer.In any case, synthesis among both methodologies gives a wider knowledge of the uncertaintiesassociated with the seismic hazard results. Finally uncertainties increase with the decreaseof the annual probability of exceedence and in sites with a seismic history of large size earthquakes.  相似文献   

试论吉林省天然矿泉水资源及其价值   总被引：3，自引：0，他引：3  

滕继奎 《吉林地质》2001,20(3):50-53

吉林省天然矿泉水资源十分丰富 ,在全国占有重要地位。本文根据大量的实际资料 ,从理论上对矿泉水的形成机制和分布规律进行了探讨。同时从矿泉水的资源属性出发 ,对其价值问题提出了新的认识。  相似文献   

Geochemistry, mineralogy, and technological properties of the main Stephanian (Carboniferous) coal seams from the Puertollano Basin, Spain     

A. Alastuey  A. Jimnez  F. Plana  X. Querol  I. Surez-Ruiz 《International Journal of Coal Geology》2001,45(4)

This study is focused on the occurrence and distribution of mineral matter and major and trace elements in the high volatile bituminous coal from Puertollano (south-central Spain). The relationship between ash behaviour and inorganic composition, as well as the possible formation of fouling and slagging deposits in boilers during the conversion process, were investigated. The Puertollano coals do not exhibit plastic properties, despite their rank, probably because of their high ash and inertinite contents.The Puertollano coal has medium to low total S content (0.48% to 1.63% db, with a mean of 1.0% db) and is characterised by relatively high contents of Si, Pb, Sb, and Cs. Some elements such as As, Cd, Co, Cr, Cu, Ge, Li, Mn, Ni, W, and Zn are also present in relatively high contents. The enrichment in a number of heavy metals could be attributed to the common sulphide ores occurring near the Puertollano coal deposit.The following trace elements affinities are deduced: (a) sulphide affinity: As, Co, Cd, Cu, Ni, Sb, Tl, and Zn; (b) aluminum–silicate affinity: K, Ti, B, Co, Cr, Cs, Cu Ga, Hf, Li, Nb, Rb, Sn, Ta, Th, V, Zr, and LREE; (c) Carbonate affinity: Ca, Mg, Mn, and B; (d) organic affinity: B.The very high Si levels and the anomalous enrichment in Cs, Ge, Pb, Sb, and Zn shown by the Puertollano coals account for the high contents of these elements in the Puertollano fly ash when compared with the other Spanish coal fly ashes.The chemical composition of the high temperature ash (HTA) is consistent with the trend shown by the ash fusion temperatures (AFT) and also with the predictive indices related to slagging and fouling propensities. Thus, the ash fusion temperatures increase with high values of Al₂O₃ as well as with the decrease in Fe₂O₃, CaO, and MgO.  相似文献   

土壤pH值及CaCO3在多目标地球化学调查中的研究意义   总被引：8，自引：0，他引：8  

朱礼学 《四川地质学报》2001,21(4):226-228

重点阐述了土壤pH值，CaCO3含量与土壤矿质元素活化之间的制约机理，从而论述了多目标地球化学调查要实现服务于农业，服务于生态环境保护的目标，就必须加强对土壤pH值及CaCO3含量调查研究。  相似文献   

高峰100号矿体微量元素特征     

苏亚汝  李蘅  邓金灿  任基林 《矿产与地质》2001,15(5):361-365

高峰100号矿体微量元素特征研究结果表明矿物的形成受花岗岩和地层双重制约。  相似文献   

吉林四平山门银矿区中,新生代构造应力场及研究意义     

冯明  郭华 《华北地质矿产杂志》1997,12(1):95-102

本文通过山门银矿区小型构造的研究，将本区中，新生代构造应力场划分为三期，即侏罗纪，白垩纪，老第三纪构造应力场。最大主压应力方向分别为ＮＷ－ＳＥ向，ＮＮＥ－ＳＳＷ向和ＥＷ向。估算出侏罗纪差应力值１０６．１ＭＰａ，白垩纪差应力值１０．１７Ｍｐａ利用白垩纪构造应力场数学模拟成果，结合物，化探资料，划分出三个成矿远景区。  相似文献   

粤西上元古界—下古生界金背景值及其与金成矿的关系   总被引：1，自引：0，他引：1  

张乾  潘家永 《地质论评》1997,43(5):547-554

粤西地区９０％以上的金矿床都产于该区上元古界和下古生界变质地层中，但区内变质地层的金背景值及其与金矿化的关系一直没有系统的资料。笔者以１８００个样品统计了上地了古界和下古生界的金背景含量，并利用地层金含量的变化规律讨论了地层与金成矿的关系，认为区内大部分金矿床是变质岩改造的产物。  相似文献   

陕西省“八五”区调新进展   总被引：2，自引：0，他引：2  

张拴厚 《陕西地质》1997,(1)

本文重点论述了陕西省“八五”期间区域地质调查方面的新进展、新成果、新发现、新资料、主要包括：前寒武纪变质杂者及岩群解体划分、显生苗地层厘定、古生物和同位素测年新资料、侵入岩谱系单位建立、变质深成岩体和造山带构造研究、填图方法新的探索与区调信息化等方面。并根据全省区调成果和资料，适当作了区域性综合研究、分析归纳。  相似文献