Advanced Materials Research Vols. 594-597

Abstract: Underground seepage discharge field in fractured rock mass surrounding storage caverns is analyzed by using discrete element method and stochastic joint-generation method. Meanwhile water pressure distributions in joints are investigated with a series of curtain pressures and compared with no water curtain. In the case without water curtain the groundwater in joints which locate the upper of underground caverns is drained out and water-seal conditions are completely unrealized. When the water curtain pressure is less than a certain value, the joints that have been drained out can not be saturated, and only the water curtain pressure exceeds this certain value, can groundwater seal the storage caverns.

Abstract: During a long time in the past, the treatment of well point has been a difficulty in academia. However well pumping is still inevitable in civil engineering circles due to its effective role on groundwater control. Firstly, the currently available treatment methods of well point are summarized. Through comparison between these existing methods and theoretical analysis, a drainage substructure is advanced, of which the inner layer is a square having equal perimeter with the actual well pipe. Results of numerical simulation upon a field pumping test prove the effectiveness and feasibility of proposed drainage substructure method, which may contribute to the well point simplification in future research.

Abstract: Based on the theory of mass and energy transfer, the coupling theoretical model of temperature and stress fields in the process of rock freeze-thaw was established considering the volume load caused by temperature change within the rock body. Taking Daban mountain tunnel surrounding rock at its exit as example, the heat--stress coupling process was numerically calculated, and the mutual influence and varied laws of temperature and stress fields were researched. The simulating result is similar to the current results and engineering experience, which can verify the correctness of the theoretical model and the reliability of calculation method, and also provide some theoretical basis for determining the engineering parameters scientifically, optimizing the lining and supporting scheme and ensuring the safety of design and construction.

Abstract: The heat transfer properties of pulsating flow around the tube with simple harmonic vibration were analyzed. The effect of the angle θ between the flow direction and the tube vibrating direction, which changes from 0° to 150°, on heat transfer properties was numerically investigated by the dynamic mesh technology of FLUENT. The results showed that the transient surface heat transfer coefficient decreases with increasing θ when amplitudes of pulsating flow or vibrating tube increase. Comparing with the still tube, the angle between the temperature gradient and the velocity vector is smaller when the tube vibrates along different directions, hence the field synergy performance is better, and the heat transfer performance is more enhanced.

Abstract: A coupled model for horizontal wells with perforation completion was built by combing the flow models in reservoir and wellbore. Then used the genetic algorithm to determine the flow rate and pressure distribution along the wellbore. The influence of the length and position of the perforation section to the production ability was also studied. The partition perforation optimization technique can uniform the inflow profile along the horizontal wellbore, prolong the develop cycle, and increase the development benefit.

Abstract: In block one of Tahe oil field, the Triassic Lower Oil Formation sand with a low-amplitude anticline has a characteristic of bottom water reservoir and a uniform oil/water contact, bottom water is energetic, natural water drive, rock and fluid depletion drive. With the continuous development, oilfield has entered high water cut stage, bottom water coning is significant, oil well has rising of the water content and production decline. Summarized influencing factors of water production and water production mode in block one of Tahe oil field. According to water production factors of oil well, we draw four kinds of water production mode: water production mode of tectonic position, water production mode of poor fault-sealing prediction, water production mode of developed into inter-layers, water production mode of high specific inflow segments. Putting forward four kinds of water production mode provide a theoretical basis to control measures for high yield water of later oil well.

Abstract: Because of its matured lifting technology and perfect supporting process, beam unit-rod pumping is applied widely in oilfield development. But as applied in low liquid production wells, the proportion of idle power consumption is large. Therefore, the lifting technology of electric submersible piston pump was studied to decrease the energy consumption. Based on the supporting technologies of electrical heating, liquid level automatic monitoring and remote control, the technology of down-hole intelligent intermittent pumping was developed, which can decrease the energy consumption, and provide technical support for the construction of digital oilfield.

Abstract: According to existing fluid-solid coupling models, reasonable range and control technology of pressure depression cone has not be formed in Putaohua reservoir. In this paper, using laboratory experiment, the relationship between rock elastic-plastic deformation, single phase permeability of oil or water and relative permeability curves has been measured and the following important facts has been established: oil well bottom hole pressure which is lower than formation pressure is in a reasonable range during the initial stage of commissioning, and a gently pressure depression cone is formed between the formation and wellbore, that can reduce the permeability loss by compaction settlement and particle migration and return to production in reasonable bottom hole pressure while the water flooding takes effect and thus enhance the oil recovery.

Abstract: Overburden fractures are the passageways for water resource loss in underground mining. A new zonation for overburden movement was present through the analysis on hydraulic aperture and permeability according to numerical calculations. Fractured zone was divided into three parts, the upper, the middle and the lower and their heights were educed. In the bedding plane, end fracture development zone and middle fracture compaction zone were defined and their range was calculated out. The achievements can be used for water resource conservation and gas prevention or drainage, etc.

Abstract: Wavelet transform by DB4 method can be applied to determine informational entropy of KARST spring hydrology conveniently. The complexity of KARST spring hydrology was described by entropy. Compared with the runoff of surface water, it concludes that KARST spring hydrology has higher complexity than the runoff of surface water.