Advanced Materials Research Vols. 734-737

Abstract: Based on the detailed core data and logging data from Toutai oil field and applying correlative technique of fluvial facies reservoir, through guiding wells selection, key beds determination, progressive oil layer subdivision of all wells, fine stratigraphic classification and correlation are carried out. The Fuyu oil layer in Toutai oil field is divided into 3 sand groups, 18 sublayers and 37 sedimentary units, consequently, monosandbody-scale isochronal stratigraphic framework is established, which can provide geologic basic data for further study on sedimentary microfacies, sand body distribution, oil and water distribution and favorable target prediction.

Abstract: Gas content is one of the most important factors in the process of exploration and development of coalbed methane (CBM). The relationships between gas content and characteristics of geophysical logs have been evaluated for the No. 5 coal seam in Weibei CBM field. It is found that the main well loggings that have good responses for gas contents are the compensating density, natural gamma-ray, compensating neutron, natural spontaneous potential and acoustic. A theoretical model was proposed to calculate the gas content by using these well logging data and as well as the burial depth. The calculated gas contents fits well with the measured data with a small relative-error of 0.38-5.05%. In the model, both tectonic movement intensity and the gas accumulation were taken into consideration. Key words: Coalbed methane, Weibei coalfield, Ordos Basin, Gas content, Geophysical logging

Abstract: In the thesis, we studied fluid inclusions in minerals and mineralization epochs of Luziyuan Pb-Zn deposits in eastern of Zhenkang Yunnan province. 240 available data have been obtined by observing characteristics of fluid inclusions in sphalerite, quartz, fluorite, calcite under microscope and selecting 284 primary inclusions and secondary inclusions thermometry. Various mineralization epochs homogenization temperature, freezing temperatures, salinity frequency histogram showed a bimodal distribution mode. The fluid inclusions in sphalerite have a greatly important,it is ore-forming fluids. Its homogenization temperature distributed in 240 to 270°C (medium temperature) and 187 to 220°C (low temperature) within the range of two, (W NaCl) salinity is 5.0% to 10.6%. According to the homogenization temperature and salinity, it can be deduced Luziyuan mineralization fluids density of 0.82 to 0.96 (gcm^-3). Draw the deposits are mainly two hydrothermal mineralization, a hydrothermal in medium temperature, another period of low and medium temperature. The two ore-forming fluids are medium salinity and medium-density.

Abstract: The Hannuoba basalts from Chifeng region, Inner Mongolia, are continental flood basalt, produced by fissure-t type volcanism in the Miocene. The basalts chemically belong to the tholeiitic series. On the whole, the petrologic compositions are homogeneous. The basalts is characterized by Al₂O₃ = 11.5%~13.0%, Na₂O> K₂O and TiO₂=1.93~3.29%, chemically belong to the calc-alkaline series with low K₂O, which are the agpaitic type; The total amounts of REE of Hannuoba basalts are lower and rich in LREE. There is a weak Eu negative anomaly and weak Ce negative anomaly. The basalts are obviously enriched in incompatible elements (K, Rb, Sr, Zr, Ba, LREE etc.), and depleted in high field-strength element (U,HREE) as well as compatible elements (Co, Ni, Cr etc.).Comprehensive studies have shown that Hannuoba basalts erupted in a stable setting within continental plate and controlled by deep fracture crossed mantle, belonging to continental rift basalt.

Abstract: The Early Permian volcanic-sedimentary sequences of Ongniud Banner consist mainly of andesite, rhyolite, perlite, volcanic breccia, tuff, tuffaceous sandstone, siliceous rock. Rock assemblage and sedimentary formations indicate that are of fore-arc basin sedimentary feature between subduction zone and island arc in Early Permian. The volcanic rocks from Elitu Formation have SiO₂=50.23%~74.83%, Mg^#=6.21~49.54, Na₂O+K₂O=5.27%~10.73%, Na₂O/K₂O=0.36~4.17, belonging to high-K cal-alkaline (HKCA)~shoshonite (SHO) series. The volcanic rocks are characterized with (La/Yb)_N=5.52~9.89, moderate - intense negative Eu anomalies, LILE enrichment such as Ba, Ra, K, Th and HFSE depletion such as Ta, Nb, P, Ti, and indicating that magma could be formed in the tectonic setting of the island arc and active continental margin related to the plate subduction. R1-R2 diagram also indicates that volcanic rocks were generated at syn-collision or post-orogenic period, perhaps representing the mid-later subduction stage of the Palaeo-Asian Ocean Plate and North China Plate. Taken together, the authors suggest that the region was located still in the Palaeo-Asian Ocean, rather than the intracontinental taphrogenic trough in Early Permian.

Abstract: The Cambrian Mantou Formation shales in northern Anhui Province, China were analyzed for major oxides and trace elements to infer their provenance of the source rocks and their depositional tectonic setting. Ternary plot of Al₂O₃-Zr-TiO₂ and Zr/Sc-Th/Sc diagram suggest that the shales were first order sedimentary of igneous rocks, and then can be used for evaluating their source provenance. Diagrams of (SiO₂/20)- (Na₂O+K₂O)- (MgO+TiO₂+FeO*), TiO₂-Ni, Th-Hf-Co and Hf-La/Th, some ratios of elements (e.g. Co/Th, La/Sc and Zr/Sc), as well as the source SiO₂ contents calculated by Al₂O₃/TiO₂ ratios indicate that intermediate to felsic igneous rocks constitute the source rocks in the provenance.

Abstract: Variation function as a main analytical tool is used for geological statistic study on grade variation characteristics of different segments in ore body 1 of the Macheng iron deposit (MID). The results indicate that the main ore body is bounded with-500m elevation, the upper grade change meets void effect, the lower grade change accords with the characteristics of spheroidal variation function and the upper change is smaller than the lower one in the general grade change. Based on fitting the variation functions of separate grade changes in different areas, the upper area and the lower area, and combined with the parameter values of each variation function, it is thought that production exploration distances that are suitable for the upper and lower ore bodies are respectively 35m and 30m in the vertical direction.

Abstract: By using the cores, drilling and logging data, Fuyu oil layer in the northern Honggang is divided into 2 long-term base level cycle, 4 medium-term base level cycles, 20 short-term base level cycles, and monosandbody high-resolution sequence strata framework is established, monosandbody isochronic correlation is achieved in Isochronic strata framework at the same time. Through high--resolution sequence stratigraphic analysis, sedimentary evolution, monosandbody distribution, sand geometry and distribution characteristics of reservoir are controlled by base-level changes in Fuyu oil layer of the northern Honggang. The lower Fuyu oil layer is dereliction prograding sequence stratigraphic modes in fall range of base-level. Space stacked form of the sand body is controlled by A/S ratio or base level changes. The symmetry of cyclic changes with the geographical location and distance from the sedimentary source.

Abstract: The Afghan-Tajik Basin is an intermontane depression between the mountain ranges of Gissar and Pamirs, and Jurassic system and Tertiary system are rich in large oil & gas resources. In order to assure sustainable supply of oil & gas from Central Asia, we deeply researched hydrocarbon geology characteristics and resource potentials. The basin belongs to paralic sedimentary environment, and develops 3 sedimentary strata: Jurassic, Cretaceous, and Tertiary. Afghan-Tajik Basin develops 3 main source rocks including clastic rocks of Jurassic, carbonate rocks of Cretaceous and mudstone rocks of Eocene. The basin develops 2 plays: Jurassic-Cretaceous play is gas containing one, and Tertiary play is oil containing one. Plaster stone and salt rock of upper Jurassic are regional cap rocks of Jurassic-Cretaceous gas pool, and creaming mudstone and muddy limestone of Cretaceous and Tertiary are regional or partial cap rocks. Migration and accumulation of hydrocarbon occur in the late Cretaceous and early Pliocene epoch. Afghan-Tajik Basin has larger exploration potentials, and residual resources are 2.4¡Á10⁸t. The potential zones are as follows, south part of basin, oil-gas structures of post-salt, reef limestone of pre-salt, and litho-stratigraphic traps.

Abstract: III oil formation of He3 section of block 1 in Jinglou Oilfield has entered the mid-late stage of oilfield development after years of steam huff and puff production. The distribution of remaining oil is scattered. This paper combines the data of core, well logging, seismic and development performance to analyze the reservoir heterogeneity. It reveals the impact on oilfield development. The area is mainly fine sandstone, siltstone and inequigranular sandstone, belonging to the river sediments, the development of fan delta and fan delta front subfacies. The heterogeneity of reservoirs and sedimentary microfacies are closely related, with moderate - strong. Well spacing near the larger region between the well and well pattern is not perfect in southern area and fault is the main purpose of tapping the potential of remaining oil in the next area.