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[en] Nowadays, the oil and gas exploration and development have been developed into the deep and complex formations. More and more abnormal pressure is encountered, which gives a great challenge to the safe and efficient drilling. Accurate description of pore pressure is of great significance to avoid drilling risk. The complexity of petroleum geology, the incompleteness of the logging or seismic data, the precision of the mathematical model and other issues can all lead to uncertainty in pore pressure prediction. The uncertainty of pore pressure is one of the fundamental causes for drilling risk. In order to address these challenges, a new quantitative description method for uncertainty of pore pressure was established. Firstly the sources of the pore pressure prediction uncertainty were analyzed. Then the uncertainties of Eaton index and normal compaction trend were, respectively, described. Finally the uncertainty interval of pore pressure was established based on Monte–Carlo simulation and normal information diffusion theory. The pore pressure prediction result obtained in this paper was not a single value, but an interval with probability distribution characteristic. The results of example showed that the measured values of pore pressure were all in pore pressure interval with confidence of 90%. Case study validated the feasibility and effectiveness of the proposed method.
[en] A compilation and generic critique of the diagnostic siting criteria now in use throughout the world to delineate or approximate bounded tectonic, seismic, or seismotectonic provinces or zones, are presented. The criteria are referenced and tabulated to facilitate determination of their regulatory, scientific and practical application to siting of important engineered structures in Canada
[en] For more than forty years, palaeopascichnids represented an enigmatic group of macroscopic fossils, which are characterised by substantial differences in preservation leading to no consistent diagnosis for these organisms. Numerically abundant palaeopascichnid fossils are globally distributed in Ediacaran sequences of the East European Platform, Avalonia, South China, Siberia and Australia. In light of new perspective to reanimate the ‘Vendian’ as a formal upper series of the Ediacaran System, Palaeopascichnida is probably the only Ediacaran fossil group whose stratigraphic range spans almost the entire ‘Vendian Series’. Furthermore, it has been considered that palaeopascichnids are among the oldest known macro organisms with an agglutinated skeleton; its presence puts emphasis on this group in terms of Ediacaran biostratigraphy and geological correlation and paves the way for the reexamination of other skeletal palaeopascichnid-like fossils.
[es]Durante más de cuarenta años, los paleopasciquínidos han representado un grupo enigmático de fósiles macroscópicos, caracterizados por diferencias sustanciales en la conservación, lo que no conduce a un diagnóstico consistente de estos organismos. Los fósiles de paleopasciquínidos se encuentran distribuidos globalmente en las secuencias ediacáricas de la Plataforma de Europa Oriental, Avalonia, China meridional, Siberia y Australia. A la luz de una nueva perspectiva para reanimar el “Véndico” como una serie superior formal del Sistema Ediacárico, los paleopasciquínidos son probablemente el único grupo fósil ediacárico cuyo rango estratigráfico abarca casi toda la “Serie del Véndico”. Además, se ha considerado que los paleopasciquínidos se encuentran entre los macroorganismos más antiguos conocidos con un esqueleto aglutinado; su presencia enfatiza este grupo en términos de bioestratigrafía y correlación geológica ediacárica y allana el camino para la reexaminación de otros fósiles esqueléticos de tipo paleopasciquínido.
[en] Huhehu Depression will be the new battlefield in Hailar Basin in the future, while at present it’s in a low exploration level. The study about the source system of Nantun group is little, so fine depiction of the source system would be significant to sedimentary system reconstruction, the reservoir distribution and prediction of favorable area. In this paper, it comprehensive uses of many methods such as ancient landform, light and heavy mineral combination, seismic reflection characteristics, to do detailed study about the source system of Nantun group in different views and different levels. The results show that the source system in Huhehu Depression is from the east of Xilinbeir bulge and the west of Bayan Moutain uplift, which is surrounded by basin. The slope belt is the main source, and the southern bulge is the secondary source. The distribution of source system determines the distribution of sedimentary system and the regularity of the distribution of sand body. (paper)
[en] Approaches followed for the preliminary studies, the selection of the restoration scheme, and the design choices that were made in the case of a 70-year old concrete water supply dam on the Charlo River, near Dalhousie, New Brunswick, were described. The significance of understanding the foundation geology, the original design approach and the behaviour of the dam under various operating conditions was stressed as key to successful rehabilitation. 6 refs., 10 figs
[en] The mid-Cenomanian Mishrif Formation (Fm.) is considered as one of the most important rudist-bearing reservoir horizons in the Sirri Oil Fields of the Persian Gulf. Due to the general heterogeneity of carbonate reservoirs, the use of an integrated approach is helpful for investigating porosity and permeability distribution along with recognizing controlling pore system factors in the reservoir. Thus, for the reservoir characterization of the Mishrif Fm., an integrated approach including facies analysis, diagenetic history and sequence stratigraphic analysis is considered. Detailed petrographic studies showed a total of eight microfacies and seven facies belts, related to inner ramp to the basin of a homoclinal carbonate ramp. Humid climatic condition and tectonic activity, associated with eustatic sea-level fluctuations during the mid-Cretaceous, led to meteoric diagenesis of the Mishrif carbonates during subaerial exposures (mid-Cenomanian and Cenomanian-Turonian disconformities). General diagenetic overprints and modifications include micritization, cementation, dissolution, compaction, dolomitization, pyritization and fracturing. Considering this reservoir in the sequence stratigraphic framework reveals that the reservoir zones development is basically related to the Cenomanian–Turonian sequence boundary, recognized in the three studied wells, and also to the mid-Cenomanian boundary, identified only in one well. In addition, pore system properties were inspected by differentiation of Hydraulic Flow Units (HFUs) within the reservoir. The identified flow units, based on their capability for fluid flow, can be classified into four main rock types with very high- (HFUD), high- (HFUC), medium- (HFUB) and low-quality (HFUA). Accordingly, this study shows that the main part of the Mishrif Reservoir is affected by diagenetic processes related to subaerial exposures, resulting in zones with higher storage capacity and fluid flow rates. So, the study of depositional and diagenetic characteristics of the Mishrif carbonates in the sequence stratigraphy framework is essential to unravel the reservoir heterogeneity, and to describe the reservoir zones and their distribution in the field and regional scale. In addition, observed changes in the thickness of hydrocarbon column are attributed to the different location of the studied wells on the anticline structures, which show a tilted oil-water contact with a slope to the North.