Advanced Materials Research Vols. 524-527

Abstract: Most of the offshore oil and gas is transported to land by submarine pipeline, and then processed. In order to decrease the fluid viscosity and increase flowing roperty, the pipeline is usually be heated. To evaluate the temperature change during oil and gas transport, this paper build the the physical and mathematical model of submarine oil pipeline, and using the software COMSOL Multiphysics to simulate temperature drop along the pipe, which provides a reliable parameters for the design of pipeline.

Abstract: In carboniferous system of Dzungaria basin, the hard igneous rock greatly decreases the drilling velocity. Gas drilling is probably the only technology to overcome this problem. However, the applicability of gas drilling technology should be investigated first. It was studied by analyzing the rock strength both experimentally and theoretically. Stress status of many rock elements near well face was tested which showed a 2D compression status rather than 3D in conventional slurry drilling technology conditions. Therefore there was a horizontal stress for underground rocks, in a similar magnitude with upper burden pressure. The domination of the confining pressure, different with normal conditions, may mislead the selection of the failure criterion. We proved the correction of the Mohr-coulomb criterion as the most suitable failure criterion in gas drilling conditions. As a result, the applicability of gas drilling technology in Carboniferous system of Dzungaria basin was concluded.

Abstract: It has been long known that the drilling hole stability is often a major issue faced by drilling workers. And for such a great challenge, a lot of work has been done both at home and abroad in the aspect of the chemical stability of wall, including developing and successfully applying such a series of drilling fluid systems as formate, oil base, synthetic base, silicate, polyol. Since silicate and polyol are often added into drilling fluid system as aggregation inhibitors and lubricants, there is no mixing use of them. In this paper, from the perspective of the comprehensive role of treating agent, the chemical effect of potassium silicate (gel sedimentation) and the physical effects of polyol (cloud point effect) are put into composite application so that a set of drilling fluid system of membrane structure and silicon potassium polyol with gel - cloud point effect is established, and a comprehensive evaluation of the performance of the system is given a complete explanation, opening up a new research direction for drilling fluid's stabilizing well wall.

Abstract: This paper adopts the multi-factor comprehensive evaluation method combining fuzzy mathematics and gray relational analysis to conduct oil field stimulation measures optimization. It overcomes the one-sidedness of the man-made assignment through the replacing correlation of ray correlation analysis with weight set of fuzzy comprehensive evaluation. The paper first analyzed the factors that affect the oil field stimulation measures, and then created a multi-factor comprehensive evaluation theoretical model, finally based on the instance to evaluate the model. The results show that the method is feasible and has high application value.

Abstract: S-16 block of YSL oilfield is fault lithologic deposit. For the practical problems of low permeability, high injection pressure causing to difficult injection and low degree of reserve recovery due to delaying the supplement of producing energy, this paper applies the module E300 of Eclipse to establishing the triaxiality and triphase compositional model of the simulated block which takes the 11Y67-611 and 11Y69-56 as the target wells, completing the numerical simulation study of optimizing parameters of CO₂ huff and puff by using of the evaluation indexes of oil increment and the oil-draining rate. It provided theoretical reference for YSL oilfield to carry out CO₂ huff and puff that its optimized parameters.

Abstract: Cyclic steam stimulation is a kind of recover method for heavy oil. Along with steam stimulation cycles increased, steam channeling interference phenomenon will appear. To solve the problem, one of the most effective methods is high temperature profile control technology. In this paper, a new type of high temperature plugging agent of tannin foam system was researched, and the influencing factors on it were analyzed. Through foam system selection and static evaluation high temperature profile control agent of tannin foam system has been selected. The formula is: foaming agent DHG-1 for 0.5%, tannin for 7.5%, formaldehyde for 4.0%, phenol for 1.0%, CaCl2 for 1000ppm. The tannin foam system can be used in steam stimulation well.

Abstract: According to the fractured sandstone gas reservoir seepage characteristics and well test theory, mathematic model and numerical model of homogeneous formation fractured sandstone reservoirs were established. Using Laplace transform to solve the model, and analyzed the sensitivity of parameters of affecting fractured sandstone gas reservoir productivity prediction curve. The result shows that the number of branch and half-length of cracks, the ratio of coefficients of pressure derivative and fracture conductivity have significant effects on gas well early productivity; the increase of the skin factor can reduce production. It provides beneficial suggestions to improve the productivity of fractured sandstone gas reservoir.

Abstract: The reserves of Chinese shale gas is very rich, but still haven’t ever formed a mature technology. According to Chinese shale gas reservoir characteristics, the development technology situation and the principle of high energy gas fracturing, the research and exploration of HEGF stimulation integrated technology which is suitable for the development of Chinese shale gas reservoir need to be carried out. Through a series of analysis and study, compositing high energy gas fracturing technology achievements, this paper discusses the research idea and feasibility of the integrated technology, formed by the liquid gunpowder fracturing technology, in-fracture deeply explosive fracturing technology in low permeability oil layers, composite perforating technology, the multi-pulse fracturing technology and the hydraulic fracturing, simultaneous fracturing ,which transforms shale gas reservoir and develops shale gas. Launching field application test is suggested, and studying the way to optimize the theory and design method of integrated technology, so as to promote the development of shale gas.

Abstract: Carbonate reservoir is one of the main controlling factors of hydrocarbon accumulation. But the exploration proved that high-quality reservoir and commercial hydrocarbon flow had no absolute corresponding relationship, high-quality reservoir just was the necessary condition of hydrocarbon accumulation. It was found that local construction highs had an important control function to hydrocarbon accumulation. So it has a realistic guiding significance to exploration that enhancing the detailed study on carbonate fracture-cave unit. This paper selected Well Block ZG7 with complex oil-water relationship as a case, and comparative analyzed the structural position, structural characteristics, reservoir characteristics and fluid producing status before and after acid fracturing. It indicated that structural position of fracture-cave unit had a crucial control function to the fluid property in it, whose high accumulated hydrocarbon and the low was water commonly. The structure of facture-cave unit had a close relationship with the fluid producing status, which differed from the variation of fracture-cave unit structure. Carbonate reservoir and local construction were the important controlling factors of hydrocarbon accumulation, under the background of high-quality reservoir, local structures and structural highs were the favorable accumulation areas.

Abstract: Subsea connector is one of the critical device used in the development of subsea wells. Analyzing the locking mechanism is important for the optimization design of it. An simple method based on freebody diagrams and simple friction theory is demonstrated to analyze the mechanical advantage of subsea connectors, which is mainly related to coefficient of sliding friction. The equation derived is plotted for different sets of friction coefficient to analyze their influences. It is demonstrated that the mechanical advantage(MA) is highest at friction coefficients near zero. Changes of a few range may alter connector clamping force by a significant factor.