Conditional simulation as a tool for measuring uncertainties in petroleum exploration

A fundamental task for petroleum exploration decision-making is to evaluate the uncertainty of well outcomes. The recent development of geostatistical simulation techniques provides an effective means to the generation of a full uncertainty model for any random variable. Sequential indicator simulation has been used as a tool to generate alternate, equal-probable stochastic models, from which various representations of uncertainties can be created. These results can be used as input for the quantification of various risks associated with a wildcat drilling program or the estimation of petroleum resources. A simple case study is given to demonstrate the use of sequential indicator simulation. The data involves a set of wildcat wells in a gas play. The multiple simulated stochastic models are then post-processed to characterize various uncertainties associated with drilling outcomes.     

New palaeomagnetic results from the Kerguelen Islands

New palaeomagnetic analyses have been carried out in the Kerguelen Islands on 32 lava flows of well-established age (20–22 Ma). Combined with previous studies, they yield a reliable pole for the Lower Miocene for the Antarctic plate: N = 59 flows. 349.9°E, 83.5°S, A⁹⁵= 6.1°. A reversal sequence reversed-normal has been identified in the Port Jeanne d'Arc section.     

北大西洋Hatton与Gardar沉积堤上等深线流活动的沉积学标志

 北大西洋东北部 Hatton 与 Gardar 沉积堤的早更新统沉积层分属两类不同的深海碳酸盐软泥。前者粗组份含量高,以有孔虫为主;后者明显变细,主要由超微化石组成。生物产率、水深、沉积速率及等深线流活动都有可能影响软泥的类型,但等深线流的改造作用最重要。本文进一步证实沉积堤是等深线流长期作用的产物,并自渐新世形成以来长期保持稳定。     

全球Schwiderski海潮模型M2分波在中国大陆产生的应变负荷潮

本文利用计算应变负荷潮的积分Green函数方法,计算了全球Schwiderski海潮模型M₂分波在中国大陆产生的应变负荷潮.根据负荷潮的分布特点,中国大陆大致可以分成以东经100°为界的东、西两个区域.在东区,负荷潮主要受太平洋海潮的控制;在西部内陆地区,除太平洋海潮外,它们还明显地受印度洋海潮的影响.根据本文计算结果绘制的M₂分波应变负荷潮在中国大陆的地理分布图,为如何正确考虑M₂分波负荷潮对应变固体潮观测结果的影响提供了重要的参考资料.     

方差分量估计理论及其在整体大地测量中的应用

本文探讨了整体大地测量平差中的方差分量估计问题,给出了自适应最小二乘配置;不仅较好地解决了各类观测量权比的确定问题,而且能够确定信号的方差因子。此外,文章还对如何更好地确定局部地区扰动位及其泛函的协方差函数作了讨论;最后通过对一个实测网进行了整体平差,并与经典平差结果进行了比较。     

波浪波长和方向提取的图像纹理分析技术

传统的波浪波长和方向分析技术是谱分析。本文从海洋波浪图像直接作图像纹理分析,在图像的每一个处理窗口,以海浪图像灰度极值点大小、个数的分布和灰度共生矩阵为基础,构造了借以区分不同海浪波长和方向的纹理测度,实现提取海浪波长和方向信息。     

Seamounts in the Central Indian Ocean Basin: indicators of the Indian plate movement

The study of seamount parameters in the tectonically most-complicated and least-understood Indian Ocean assumes importance since their properties vary as a function of tectonic setting, physics of lithosphere, conduit geometry and chemical composition of magma. More than 100 such seamounts ranging in summit height (h) from 300 to 2870 m, are indentified in the oceanic crust between Indian continent and Mid-Indian Ridge (MIR) and South-East Indian Ridge (SEIR). Most of the minor seamounts (h > 1000) are found in the southern part of the study area. Major seamounts (h < 1000 m) are roughly distributed in two groups—the northern group on Cretaceous Oceanic Crust and southern group on Pliocene-Miocene Oceanic Crust. On an average northern group seamounts (SM 1 to 6) are taller, wider and flatter than those from the southern group. These seamounts appear to be the result of continuous growth from tapped, moving magma chamber while stress depleted magma and inconsistent Indian Plate movement during Mid-Tertiary are attributed to the origin of southern group of smaller seamounts. Distribution and morphology of seamounts as a whole indicate their formation either from Reunion hotspot or from two separate hotspots in the geological past.     

Entrainment of circumpolar water in the Indian Ocean region of the Antarctic

The net influx of the circumpolar water on the western (approximately along 10°E) and eastern (approximately 115°E) boundaries of the Indian Ocean, adopting the method of Montgomery and Stroup is computed on bivariate distribution of potential thermosteric anomaly and salinity to identify the characteristics of the flux. The zonal flux at both the boundaries indicates an alternate strong easterly and westerly flow between 36°S and 45°S, south of which the flow is mainly easterly but weak up to 56°S. At the western boundary the easterly flow is 146 Sv and westerly is 98.07 Sv, while at the eastern boundary (115°E) the corresponding fluxes are 123.46 Sv and 27.20 Sv respectively, indicating a net outflux of 48.33 Sv. This water should have been accounted by the melting of ice and influx of the Equatorial Pacific Ocean Water.