Advanced Materials Research Vols. 962-965

Abstract: Wuerxun Sag is one of the main oil and gas exploration and development zones in the Hailar Basin. Comprehensive research on the sequence architecture and depositional filling during the Early Cretaceous shows that filling sequences are controlled by tectonic evolution and have distinct phases. The sequence configuration can be divided into three types: steep-slope type, step-fault type and deep sub-sag type. Tectonism controls the sediment distribution process and sand accumulation. Results show that different tectonic units have characteristic sequence styles and depositional systems. Different sequence patterns also determine different kinds of reservoirs in different tectonic units. The fault-controlled steep-slope area mainly develops fault nosing structure reservoirs and fault lithologic reservoirs; step-fault belts in gentle slope areas develop fault-block reservoirs and fault-lithologic reservoirs; in deep sub-sag areas sand lens reservoirs develop. In addition, the margins of deep sub-sag areas probably develop fault-lithologic reservoirs.

Abstract: The main accumulating rock types of Yingshan Fault Depression in Songliao Basin were various volcanic lava and volcanic breccias, and the accumulating spaces included primary and secondary two kinds. Though the primary accumulating spaces took the small proportion, they provided favorable conditions for paulopost reconstruction. The development and evolution of volcanic rock accumulating spaces can be divided into four stages. The first is the forming stage of primary accumulation spaces, and the secondary is weathering and leaching stage. These two stages are dominated by construction. The third is shallow burying and structural fracture developing stage, with coexisting of construction and destruction, but dominated by construction. The fourth is deep burying stage, which is dominated by destruction.

Abstract: Through comprehensive study on the combination of each accumulation of Putaohua Reservoir in Xingnan area of Daqing Placanticline, analyzing the controlling factors of hydrocarbon accumulation, accumulation rule and the corresponding exploration ideas, Enriching and developing the study of non-structural reservoir in slopes and depressions of Daqing Placanticline. The study shows that faults are well-developed, especially oil source faults which were active during the crucial moment of hydrocarbon accumulation, as for connecting source rock and reservoir and poor sealing capacity, they are the main passage for hydrocarbon migration. The relations between oil source faults and reservoir greatly restrict the distribution and scale of reservoirs. Accurate evaluation of the relationship between faults and reservoirs has an important significance which can give a guide to the surrounding exploration of Daqing oilfield and improve the success rate of exploration.

Abstract: Based on geological background, this study is to understand the potential of tight oil of Qingshankou Formation in Songliao Basin by comparing lithofacies features, oil-generating conditions and reservoir characteristics. Hundreds of samples are analyzed to derive geochemical parameters, such as organic richness, kerogen type, and source rock maturity. The results indicate that source rocks of Qingshankou Formation are organic rich, contain oil-prone kerogen, and are thermally mature. The tight reservoir of Qingshankou Formation has complicated pore throat structure, abundant fractures, and an beneficial place for oil accumulation.

Abstract: Coalbed methane (CBM) productivity is influenced by various factors. Based on field production data and test data of southern Qinshui Basin, factors including geological factors, engineering factors and drainage factors that affect CBM productivity are analyzed. Analytic hierarchy process (AHP) is introduced to calculate the contribution of each parameter to CBM productivity. A three-level model for evaluating CBM productivity based on AHP is established. The results show that average daily gas production of single well in southern Qinshui Basin increases with gas content, coal seam thickness, permeability, porosity, gas saturation, critical desorption pressure. Filling minerals in pores and fractures of coal can decrease gas content, porosity and permeability of coal reservoir. When burial depth is deeper than 500m or reservoir pressure is greater than 2MPa and burial depth is shallower than 1000m or reservoir pressure is less than 10MPa, CBM productivity is relatively high. According to the calculation, the weight of geological factors, engineering factors and drainage factors are 50%, 25% and 25%, respectively. Reservoir physical properties, geological conditions, fracturing technology and drainage process have the most impact, the weight of which are 33.33%, 16.67%, 11.79%, and 15.00%, respectively.

Abstract: Erlian Basin was composed of many small faulted lacustrine basins in early Cretaceous period. Delta systems were developed and were the most important sandstone reservoir in the gentle slope of faulted lacustrine basins. The paper took an example of Tanan sag, which was one of the most representative faulted sags in Erlian Basin. This paper analyzed the depositional characteristics of nearshore subaqueous fan systems and fan deltas systems, based on core data, logging data and grain size probability curve. Fan delta-lacustrine deposition system and near shore turbidite fan-lacustrine deposition system were the most developed deposition system in the study area. The lake basin belonged to “narrow basin deep water” type. Mud stone of Deep lake facies and sand stone of fan delta facies in Aershan formation are the best lithology association which would be explored oil and gas in Tanan sag.

Abstract: Gas shales have a complex pore structure. Using mercury porosimetry and nitrogen adsorption experiment on shale of Longtan Formation in southeastern of Hunan, the pore structure characteristics were contrast analyzed, influencing factors and its impact on reservoir-forming were discussed. Longtan Formation shale is composed of nanopores, include the cylinder pores with two ends open and parallel-plate pores with four sides open. The efficiency of mercury ejection ranges 31.45%~63.82%, 51.94% on average, pores uniformity is well. The size of nanopores is 5~30nm, taking up 94.74% of the total volume and 98.08% of specific surface area. Brittle minerals content is high, as an important parameter influencing pore development. The nanopores have a strong ability to absorb gas, methane molecule exist in a structured way.

Abstract: In this paper we use new field data, fluid inclummsions, and table isotopes (O, H, and S) to refine the roles of the hydrothermal evolution, evaluate changes in the hydrothermal fluids of Duobaoshan porphyry Cu (Mo) deposit and Sankuanggou skarn Fe-Cu deposit. Four ore-forming stages are recognized at The Duobaoshan porphyry Cu (Mo) deposit. Fluid inclusions are abundant in quartz of various stages. Estimated trapping pressures for stage I, II, III are 110-160MPa, 58-80MPa, and 8-17MPa, corresponding trapping temperatures are 375-650°C, 310-350°C, 210-290°C. The δD and δ¹⁸O values of fluids indicate a evolution process from magmtic hydrothermal fluid to a mixing magmtic and meteoric fluid. The δ³⁴S values of sulfides mainly suggest predominantly source of deep magma chamber.

Abstract: Based on the existing research results and field survey data, this paper analyses and evaluates the rule of land deterioration and ecological environment problems caused by mining subsidence. Besides, the author puts forward the corresponding control measures for the effective exploitation of underground resources, land resources and ecologic environment protection.