Advanced Materials Research Vols. 734-737

Abstract: The gas-water relations of low-permeability tight sand gas reservoir are complex and not necessarily linked to the structural relief, phenomenon that water is distributed in high structural position while gas in low structural position is common what makes it difficult to make a refined description of gas-water relations and distribution low. The article takes Zizhou gas field for example, establishes 4 gas-water relations modes of single well to analyze some profiles where there is abnormal phenomenon water up gas down, the fact is that water and gas are distributed in different sand bodies and Zizhou Gas Field is not a deep basin gas reservoir. The research shows the phenomenon that water up gas down does not exist, the gas-water relations are normal. The research results have certain significance for the determination of gas-water distribution law.

Abstract: The geological structure is an important factor of gas occurrence in coal seam, and the gas occurrence in deep coal seam should be paid attention to enough because the occurrence was more controlled by geological structure and influence. Taken Fengfeng coalfield as target in this paper, the geological structure of this coalfield was described. The deep coal mining district which is monoclinic structure in Fengfeng is located in the east of Gushan anticlinoria, which the junior small anticlines and synclines of the sub-echelon are well developed. And regional fault structures are intensive, the pressure structure is the major structure among this region. The characteristics of geological structure in Fengfeng coalfield were analyzed. The tensional structure planes and pressure structure are the major effect factors, and the latter is the main form of gas occurrence in deep. Some suggestions on safe of deep mining in high gas environment is also put forward, in order to provide theoretical support for the deep coal mining and gas disaster prevention.

Abstract: Haqian wellblock has a very good prospect in Dzungaria Basin, as it developed many faults and some formations are truncated, the development situation of it is very complicated, in this paper, we applied 3D geological modeling method which is one of the most important technology methods in describing the underground development situation, to illustrate the intricate structure. This geological model involved computer modeling and visualization of geological fault in 3D, the type of data of geological faults based on geological exploration is analyzed, after the fault model and horizon model are built, a whole structure model is finally set up.

Abstract: Based on the lithofacies mapping and petrographic studies, the mineralization-alteration zoning and mineralization process of the Maoping Pb-Zn deposit are discussed. Three ore body groups of the Maoping Pb-Zn deposit have similar transversal zoning, which is characterized by different mineral assemblages from the ore body center to outside. The mineralization-alteration can be divided into diagenetic stage, massive sulfide-carbonate stage, veined sulfide-carbonate stage, and supergene stage. The massive sulfide-carbonate stage is main Pb-Zn mineralization stage. The established zoning model and indicators can be used for ore prospecting.

Abstract: Study on the characteristic of the transition zone in CO₂-oil system has important meaning for the research of CO₂ miscible flooding. In this paper, one of crude oil samples in Xinjiang oilfield was taken as an example. The minimum miscible pressure (MMP) of CO₂-oil system was confirmed through laboratory experiment and numerical simulation separately. And the characteristic of the transition zone was analyzed. The transition zone size and interfacial tension in miscible process were quantified. And their variation tendencies along with the change of the pressure and CO₂ injection volume were studied. The results show that it is easier to reach miscible state in higher pressure and CO₂ injection volume. This work provides a reference for the further research of CO₂ miscible flooding.

Abstract: The shield tunneling will be bound to disturb surrounding strata, induced stress redistribution in soil, soil deformation and surface subsidence. We analyzed characteristics of soil disturbance by shield tunneling with numerical simulation. To provide technical support for the future urban shield tunnel construction. It shows practically significant in studying shield tunnel construction.

Abstract: The Huanghekou Sag, as an important oil-bearing zone, is located in the southeastern part of the Bohai Bay basin. It has higher values for petroleum exploration-especially in Neogene. The Neogene was a depressional lacustrine period and was characterized with both tectonically stable and gentle topography. Thus it is difficult to identify and subdivide sequences using the traditional method. Based on the practical geologic setting and current data of the Neogene of Huanghekou Sag, using the new method to set up the isochronous sequence stratigraphic framework. By analyzing climate cycle, drilling well and logging cycle, seismic cycle and the identification of unconformity of seismic and drilling well and logging data, the Neogene was divided into 5 third-order sequences and 10 systems tracts. In different sequence sets and systems tract, which was controlled by climate, ratio rate between sedimentary being supplied and accommodated, the sand body scale was different.

Abstract: Three coals (Jincheng coal, Hancheng coal and Shan-bei coal) varying widely in coal type have been treated with anionic surfactant Sodium Dodecyl Sulphate (SDS). The effect of SDS on wettability of coals was explored by contact angles and zeta potentials characterisation techniques. Results obtained show that the addition of SDS can obviously improve the wettability of coals, and as the coal rank decreases, the wettability increases under investigation. Moreover, the wettability obviously increases with the significant decrease of particle size. The zeta potential for each coal, in the absence of surfactant, is negative, and the potential becomes more negative with the addition of SDS. Meanwhile, the FTIR spectrogram was used to test the changes of-COOH and-OH to analyze the reason for change of wettability, the results show that the wettability changes may be attributed to that the negative active ions of SDS are adsorbed on the coal surface, resulting in the increase of hydrophilic groups of the coal surface.

Abstract: Artificial ground freezing method was employed in the rehabilitation project of a subsea tunnel. To ensure safety of the subsea rehabilitation work, special design and research were conducted considering the unfavorable influence of the salt in seawater had on freezing effect, such as thickness thinning and strength loss of the frozen wall. A shell-shaped frozen soil wall was designed to cut off the leakage channel into the shield. Double rows of vertical freezing pipes with limited-depth freezing were settled in front of the cutter head, and auxiliary freezing pipes were settled at the sides of the shield to achieve the design goal. Results of analyzing monitoring data on frozen soil temperature showed that the design was reasonable for shield rehabilitation in subsea stratum.

Abstract: In the general, the rock mass rupture will produce a certain energy of seismic waves around the spread, the seismic waves can be received and recorded by microseismic monitoring instruments. The rupture positioning is done by using the "four - four composite positioning" software, which records the rupture waveforms for different observation points and further determines the source location.