可地浸砂岩型铀矿床上地气异常规律的初步探索

本文通过模型实验论证了在砂岩型铀矿床上形成的地气异常。并在新疆 511铀矿床进行了试验研究测量 ,初步探索了地气异常规律。试验研究结果表明在可地浸砂岩型铀矿床上能够形成清晰的地气异常 ,但对一些地气异常为何偏离铀矿体的空间对应位置 ,还有待深入研究。

Mechanism of petroleum migration and accumulation in western China's superposed basins

In western China, most petroliferous basins are superposed due to their multi-periodic tectonic evolution, and the mechanisms of petroleum migration and accumulation are so complex that much more sophis- ticated methodologies are necessary for depiction of these mechanisms and identification of petroleum occurrences. For this purpose, in this article, a new methodology was formulated which includes： （I） ver- tical identification of petroleum migration and accumulation fluid dynamic systems in the superposed basins; （2） analysis of the effect of large scale regional faults and fault combinations on the fluids exchange between the vertically identified different systems; （3） analysis of petroleum migration and accumulation in each vertically identified system, and establishment of appropriate geological model of petroleum migration and accumulation for each vertically identified system. Using this methodology, the satisfactory results obtained in the Lunnan Uplift of Tarim Basin and Ludong Uplift of Jungar Basin case studies are： （1） existence of different vertical fluid dynamic systems in western China＇s superposed basins which are very necessary for understanding the mechanism of petroleum migration and accumu- lation; （2） in deep system, long-distance lateral petroleum migration and accumulation mainly take place along the long time exposed unconformity with weathered, fractured or karst reservoir rocks; （3） regio- nal faults are the main conducts for fluids migration from deep system up to middle and/or upper sys- tems. As to middle and/or upper systems, regional faults play a role of ＂petroleum source＂. Small faults within middle and/or upper systems conduct petroleum to carrier beds with less impeding force; （4） petroleum migrated from deep system vertically up to middle and/or upper systems will migrate lat- erally in carrier beds of these systems and accumulate to form nools near or far from faults.

Accumulation conditions of outside source heavy oil in NepaBotuoba Sub-basin,Russia and prediction of distribution

In terms of tectonic evolution and petroleum geological conditions of the Nepa-Botuoba Sub-basin and its adjacent su4b-basins,the accumulation conditions of the heavy oil were analyzed. The studied area had plenty of oil and gas accumulation,but there were no developed source rocks. It is a typical outside source accumulation,whose origins from thick high-quality source rock deposited in the adjacent sub-basins. The shallow layer has favorable heavy oil reservoir conditions and poor sealing conditions,which benefits the thickening of hydrocarbon. The multi-periods of structural compression not only uplifted the studied area drastically,but also created a series of fault zones and large-scale slope belt. The structural compression also provided channel and sufficient power for migration of hydrocarbon to shallow layers. Based on these conditions,the favorable accumulation zone of heavy oil was predicted,which provided direction for heavy oil exploration in Nepa-Botuoba Subbasin.

Discovery of “Enveloping Surface of Oil and Gas Overpressure Migration” in the Songliao Basin and its bearings on hydrocarbon migration and accumulation mechanisms

The Fuyang oil layer of the Songliao Basin is a tight and low-permeability sandstone pay zone formed in the fluvial-shallow water delta environment.In the formation are mainly lithologic reservoir and tight reservoir.The lacustrine-mudstone of K2qn1 is a good source rock and also acts as a good regional cap rock.The Fuyang oil layer is a typical upper-source and lower-reservoir pattern distributed in a large area.Based on a large number of exploration and development data, a macroscopic enveloping surface is found developed in the Fuyang oil layer, which is below K2qn1.The effective reservoirs within the enveloping surface are commonly saturated with oil, and below the enveloping surface are mainly water layers.The distance from the enveloping surface to the bottom of the source rock is usually 100-350 m and at most 550 m.Through the research of the distribution patterns and the physical properties of the sandbodies above or beneath the source rock, it is concluded that: 1) the enveloping surface is the boundary of the overpressure hydrocarbon migration; 2) the spacial distribution of the pressure release beds controls the direction and the distance of the overpressure hydrocarbon migration; 3) tight oil reservoirs and lenticular oil reservoirs are mainly formed inside the envelope surface, whereas, conventional reservoirs are formed outside the envelope surface as a result of the buoyancy hydrocarbon migration.The discovery of the "overpressure hydrocarbon migration enveloping surface" and the concepts of overpressure hydrocarbon migration and buoyancy hydrocarbon migration not only challenge the old notion that "hydrocarbon migrates along the faults and is distributed along fault belts" in the Fuyang oil layer of the Songliao Basin, give a new explanation to the long-distance-oil-downwards migration (hundreds of meters) and expand the exploration potential of the Fuyang oil layer, and provide a rational guidance to the exploration of syncline plays, but also better categorize tight oil/gas and conventional reservoirs in all of the key elements related to hydrocarbon migration, accumulation, reservoir characteristics and oil and gas spatial distribution.

Polar Motion Excited by Atmosphere and Ocean in Multi-frequency Bands

This research aims to study the influences of the atmospheric and oceanic excitations on polar motion.Power spectrum density analyses show that the efficiencies of the atmospheric and oceanic excitations differ not only at different frequencies but also in the retrograde and prograde components,but the sum of atmospheric and oceanic excitations shows the best agreement with the observed excitation.