Advanced Materials Research Vols. 634-638

Abstract: The buckling deformation and stress distribution of the tubing nearby the packer would be seriously influenced by the packer constraints. This paper focused on the Strength analysis of transitional segment. The method to calculate the buckling deformation and the equivalent stress of transitional segment were derived considering the tubing boundary and continuity condition, adopting the fourth-order nonlinear ordinary differential equations and helical buckling strength method. This study makes up for the weakness of traditional stress analysis of the buckling tubing nearby the packer in vertical well, improves the pertinence and accuracy of stress analysis of buckling tubing. The results of analysis show that with the axial pressure increasing lead to the length of the transitional segment irregular fluctuations and the maximum equivalent stress increasing. The equivalent stress would gradually reduce and finally approach a constant.

Abstract: Aim at gob in loess gully region is the only ways of West—East oil and gas pipeline, the risk assessment on oil and gas pipeline through gob is solve operation of pipelines, and prevent the occurrence of major disasters and urgently need to study and solve major problems. It combines with integral method to further risk assessment on oil and gas pipelines across god based on the results mining subsidence hazard study in loess gully region. The method has proved that has some guidance on risk assessment of oil and gas pipelines through the loess gully region, and it is for further study on overlying gob pipeline movement and deformation to lay the theoretical basis.

Abstract: Note CO2 gas development has become a very effective reservoir mining method in low permeability oilfield of Daqing outskirt. It can effective enhance the recovery ratio. When the crude oil dissolves CO2, the volume expands and the viscosity decreases. Under the same conditions of temperature, expansion increases with pressure, CO2 drive is more effective than a single water drive, the degree of reserve recovery has been significantly improved, generally 1.3-1.4 times. Field tests shows that the input-output ratio in swallowing- spitting test of CO2 producing in formation could reach 6.25.

Abstract: This submarine pipeline was used to transport water originally, however, it is an oil-gas mixed transportation pipeline without heat preservation now. Because of the differences between the physical properties of oil-gas and water, we should take the gas and liquid viscosity, density and interfacial tension and other factors into account to establish a new submarine pipeline pressure drop model .In this passage, according to the field data provided by the 20B platform, 20A platform, 251B platform, cb502 platform of submarine pipeline, we apply the methods of comparative analysis and mathematical simulation to establish Beggs-Brill submarine pipeline pressure drop model and the temporary oil-free thermal insulation of the pressure drop and mathematical model, we also make the analysis of a variety of factors impacting on the pipeline pressure drop, including the starting temperature of media, gas liquid flow rates, pipe diameter, angle of inclination，Provide a reference basis to design submarine pipeline.

Abstract: This document has firstly been established explosion combustion velocity model in trasport pipeline, analysis on gas temperature effect on dust explosion strength. Gas temperature at 40 °C~ 60°C on the potassium clavulanate mixed dust explosion experiment are studied in the pipeline. The experiment indicates that dust explosion pressure change as gas temperature at 40°C, 46.3°C, 50.5 °C, 54.1°C, 55.8°C, 59.7°C, The studies show that gas temperature rise causes dust explosion pressure pipeline center development,bring piston wave phenomenon.Dust explosion pressure maximum value is get up to 375kPa and negative pressure value is 875kPa.

Abstract: Steel 406 is a high strength steel, generally used for military equipment. Finite element analysis software was used to comparatively analysis perforating gun between the original structure and modified structure. AUTODYNE software was used to compare the speed, total energy and kinetic energy of the two jet structure. It was proved that the use of 406 steel instead of high-strength material, decreasing the thickness of 6.75mm, the structural strength meets the requirements, the stability of the structure to meets the requirements. Jet speed and kinetic energy increases，while total energy reduce little. The maximum speed increases 5.9%. After replacing material, the weight of the guns was reduced, jet penetration depth increased, so the revised design was better.

Abstract: With the increment of the oil-field extract strength and the pipeline infusion load, the pipeline damage had become more serious and the effective use of cycle got shorter. Pipeline damage mainly appeared pipeline corrosion. The pipeline corrosion mainly occured in the place of pipe's repaired mouth and mending of blemishes. In this paper, through failure analysis of the pipe's Heat Shrinkable Wraparound Sleeve (HHWS) repaired mouth, we found the failure modes and failure causes of the repaired mouth of the existing pipeline and new pipeline, and grasped the failure mechanism. Then, improvement measures and suggestions were proposed to prevent failure, ensure safety, improve quality of the pipe's repaired mouth, slow or prevent pipeline corrosion and extend pipeline life.

Abstract: Computational fluid dynamics software were carried out to simulated the spiral flow field of using RANS(Reynolds-averaged Navier-Stokes) turbulence models.The physical model was established with the software Gambit.Under the condition that the gas velocity is 9000m3/h. The results shows that the intake way have a major impact on spiral flow field. The model with a circular intake has a stable spiral flow field, a smaller negative pressure area and less number of secondary vortexes then model with a square intake. The center of spiral flow field is coincident with the geometric center of the cylinder.

Abstract: In order to determine coal seam gas content accurately, the single factor method was adopted to study geological factors that affect coal seam gas content of a coal mine. Bedrock depth, 50m influence coefficient and coal thickness are identified as the main controlling factors of gas content. And the corresponding correlation coefficient are: 0.6011, 0.3899, 0.2527. Factors such as effective trapping thickness, moisture content and ash content are regarded as secondary factors. Then the SVM theory was used to set up a nonlinear prediction model between coal seam gas content and main controlling factors, and the gas content was predicted. Results show that single factor method can be used to determine main controlling factors of coal seam gas and the gas content SVM model can predict gas content accurately. Besides, the research findings can provide technical basis for gas drainage and gas outburst prevention.

Abstract: To prevent the top corner gas on coal face concentration exceeded and the gas accident, The influence factors of gas concentration were analyze, the model of top corner gas concentration forecast was constructed based on chaos theory, and analyzed the real gas concentration data, forecasted the future data of the coal mine. The results show that top corner gas is influenced by the factors such as ventilation way, gas content, coal output and so on, the maximum Lyapunov exponent is 0.068, the time series is chaotic, and in the phase space, time delay is 4, embedding dimension is 3, the model parameter a is 1.221 7, b is -1.044 7, the absolute error is -0.024~0.031, the relative error is -2.82%~3.99%, and RMSE (root mean square error) is 0.014 9, the predictive results tally with the real ones, which can guide gas management work.