油气层综合解释中应把握的几项宏观原则

油气层综合解释的方法很多,但目前多数方法的应用效果并不十分理想。笔者以多年的工作实践为依托,认为其主要原因之一是综合解释人员没有系统地进行地质综合分析,就此提出在注重方法的同时,综合性、针对性、相对性以及从成藏角度进行综合分析是综合解释工作中应该把握的宏观原则。

Experiment and Simulation of Large Capacity Air-guns in Deep Structure Exploration

The air-gun source has important applications as a new, environmentally, green active source in regional scale deep exploration. In the past, the air gun source was used mainly in smallscale, high-resolution shallow oil exploration, but has a lack of adequate research in deep exploration. In order to study the selection of work parameters and field conditions of the air gun source in deep exploration, this paper does the following work： （1） analyze the characteristics of the air gun source using air gun experiments; （2） simulate the air gun signal and air gun-array signal based on the theory of free bubble oscillation to analyze the influence of bubble oscillation and study the wavelet energy and spectrum characteristics needed in deep exploration; （3） on the basis of theoretical simulation, study the influence of work parameters, such as air-gun capacity, work stress and depth on air gun signal and analyze the influence of air-gun array inspired moment and spacing of different air guns on air gun-array signals; and （4） study energy reflection and transmission coefficients for different underwater interfaces, which is very useful for choosing suitable field conditions.

Dynamic development characteristics of amounts of gas and levels of pressure in the Pan-1 coal mine of Huainan

The Pan-1 coal mine located in Huainan municipality, Anhui province, is abundant in coal resources. In order to discover the natural conditions of gas in its coal seams, we inverted the burial history of these coal seams using the software of Easy%Ro method and simulated the development process of gas volumes and pressure of the major coal seams using CBM History Simulation Software. Our analysis shows that the devolution of gas volumes and levels of pressure can be divided into four stages: i.e., a biogas stage (P1-P3), a pyrolysis gas stage (T1-T2), an active gas enrichment stage (T3-K1) and a gas dissipating stage (K2-present). Currently, the average amounts of gas and gas pressure in coal seams Nos. 13-1, 11-2 and 8 of the Pan-1 coal mine are 8.18 m3/t and 2.20 MPa; 3.89 m3/t and 2.47 MPa and 6.35 m3/t and 2.89 MPa, respectively. This agrees very well with current mining data.

Computerized methods of analyzing faults between wells

The analysis of strata between wells is fundamental in the study of oil and gas reservoirs. Automatic analysis of strata between wells, based on stratigraphic division of well logs, is realized using computer techniques. We use a technique of dynamic waveform matching to build cross-well stratigraphic correlation relationships and automatically draw a path diagram of the cross-well stratigraphic contrast through piecewise line fitting, log character extraction, match cost calculation, and etc.. After analyzing many structure path diagrams between wells, 30 path patterns for normal faults, reverse faults, unconformities, synsedimentary faults, listric faults, pinch-outs, and so on were summarized and the path diagram patterns and correlation conceptions are presented. The application analysis in Dagang Oil Field shows that this method is effective.

An Assessment and Identification of Avalanche Hazard Sites in Uri Sector and its Surroundings on Himalayan Mountain

Avalanches are one of the most natural hazard in the mountain areas and therefore, identification of avalanche hazard is necessary for planning future development activities. The study area falls under the international boundary region which generally covered by the snow(38%) on high altitude regions of the western part of Himalayas. Avalanches are triggered in study area during snowfall resulting in loss of human life, property and moreover the transportation and communication affected by the debris which ultimately delays the relief measures. Therefore in this study three major causative parameters i.e terrain, ground cover and meteorological have been incorporated for the identification of avalanche hazard zones(AHZ) by integrating Analytical Hierarchical Process(AHP) method in Geographical Information System(GIS). In the first part of study, avalanche sites have been identified by the criteria related to terrain(slope, aspect and curvature) and ground cover. Weights and ratings to these causative factors and their cumulative effects have been assigned on the basis of experience and knowledge of field. In the second part of the study, single point interpolation and Inverse Distance Weighted(IDW) method has been employed as only one weather station falls in study area. Accordingly, it has been performed to generate the meteorological parameter maps(viz. air temperature and relative humidity) from the field observatories and Automatic Weather Stations(AWS) located at Baaj OP in Uri sector. Finally, the meteorological parameter maps were superimposed on the terrain-based avalanche hazard thematic layers to identify the dynamic avalanche hazard sites. Conventional weighted approach and Analytical Hierarchical Process(AHP) method have been implemented for the identification of AHZ that shows approximately 55% area under maximum hazard zone. Further, the results were validated by overlapping the existing registered avalanche sites. The sites were identified through field survey and avalanche data card followed by its delineation from the toposheet(1:50,000 scale). Interestingly study found that 28% area under moderate and maximum AHZ correlated well with registered avalanche sites when they were overlapped. The accuracy for such works can be increased by field survey under favorable weather condition and by adding data from more number of AWS for predicting avalanche hazards in mountainous regions.

A comparison study of the simulation accuracy between WRF and MM5 in simulating local atmospheric circulations over Greater Beijing

Several multi-scale numerical simulation experiments were carried out using the mesoscale modeling systems MM5V3.7 and WRFV2.2 for Greater Beijing to estimate the accuracy of WRF and MM5 in simulating the characteristics and variations of mesoscale local circulation in the atmospheric boundary layer of this area. We simulated the horizontal distribution and diurnal variations of temperature and wind fields near the ground and compared them with Automatic Weather System (AWS) data collected from 19 AWS stations in Beijing. Correlation and error analyses were also made. The modeling and statistical results showed that both WRF and MM5 model the temperature field near the ground significantly better than they model the wind field. The temperature field simulated by MM5 is more coincident than that of WRF with the AWS observation records, while WRF does better than MM5 in simulating the wind field, especially under the condition of gusty wind. Neither WRF nor MM5 can capture the fine structure of urban architectural complexity, which is the main error in the wind field simulation. Both models underestimate the land surface temperature at night and overestimate the temperature during the day. All the above results are supported by statistical analysis.