Applied Mechanics and Materials Vols. 675-677

Abstract: The United States has taken the lead to achieve the shale gas industrial production and created a shale gas revolution throughout the world. According to the exploitation experience of the United States, the key of shale gas business development realization is to adopt horizontal well combined with fracturing technology. At present fracturing technology used commonly include multi-stage fracturing, water fracturing, refracturing, etc. China has great potential in shale gas resource, recoverable resources has 25.08×10¹²m³, but they are mainly located in the drought and water lack area, and the clay mineral content for shale gas reservoir is higher, the traditional water-based fracturing fluid used for shale gas development caused a lot of water consumption and serious reservoir damage, therefore, it is not suitable for shale gas reservoir conditions in China. In the process of domestic shale gas development, exploring novel fracturing and development technology is irreversible.

Abstract: The fine grain, poor sorting and high cement content in low permeability reservoirs lead to poor reservoir property, low porosity and permeability and have strong damage to the reservoir .The conventional way of low permeability oil mining is mainly fracture and chemical flooding, which cost is relatively high and will cause serious irreparable damage to formation. People are in favor of physical oil production technology because it is no harm and pollution to the reservoir, more flexible to operate and it has wide range of application and low cost. By using high frequency pulse pressure servo system and ZC-type I, this paper examines the low-frequency vibration oil recovery indoor simulation test device hydraulic pulse oil displacement effect of low permeability cores. The experiment selecting the artificial core (permeability are less than 50), examines the effects of different hydraulic pulse parameters (frequency, static pressure and dynamic pressure) on low permeability core permeability and recovery factor. The results showed that only when the three parameter ,hydraulic pulse frequency, static pressure and dynamic pressure, suitably combined will greatly increase the reservoir recovery efficiency and reduce residual oil saturation.

Abstract: The displacement performance of heat-resistant polymer is evaluated with the artificial cores and natural cores under 95°C. The best concentration of BH heat-resistant polymer is 1500 mg/L, and the best slug is 0.6 PV on the condition of the average permeability is 600×10^-3μm² of the homogeneous core and the oil viscosity is 2.3mPa • s. Under the best concentration and the PV size, BH heat-resistant polymer solution has better displacement effect for the artificial double core whose permeability ratio is less than 4. When permeability ratio exceed 4, the displacement affect no longer increase. When the mobility ratio increase from 0.05 to 0.2, for the artificial cores, the recovery of polymer flooding reduce by 3.17%, and for the natural cores, the recovery of polymer flooding reduce by 2.26%. The recovery of BH polymer that is aged for 90 days after vacuumed is 32.29%. Comparing with the fresh BH polymer, it is lower by 6.56%. That is to say that the aged BH polymer still has good oil displacement efficiency.

Abstract: Compound perforation fracturing technology is a space combination type ultra-deep perforating that can overcome some flaws conventional perforation has, such as shallow penetration and compaction damage. It can remove the compaction band and near wellbore pollution in rock matrix which results from conventional perforation. This paper introduces the theory of effect and influence factor of compound perforation fracturing technology and summarize the advantages for low permeability gas well on the basis of analyzing the mechanism of action about increase production of compound perforation. In order to evaluate the effects of application of this technology in in low permeability reservoir, 11 compound perforation wells and 12 conventional perforation wells were selected which have the similar physical property and the evaluation was conducted in two blocks. The results show that compound perforation can make the formation fracture pressure decrease in 3~5MPa and increase the permeability near the perforation channel. This technology has better effects than the conventional and decrease the cost effectively, improving production in low permeability oil and gas field.

Abstract: The screen pipe completion is the predominated method for heavy oil horizontal well in Liaohe Oilfield, accounting for 83.4% of the total completions. General steam injection has been used for the horizontal wells, resulting in a better exploitation percentage in heel part but a poorer exploitation percentage beyond 1/3 of the distance from the tiptoe to heel in horizontal well. As the concentric dual-tube steam injection technique for horizontal well has just been developed in Liaohe Oilfield, the related supporting technique is not enough. In this paper, researchers consider achieving horizontal wells concentric dual-tube steam injection optimized design as main goal so that the physical model will be established, and also the calculation methods for pressure, the calculation models for quality, heat loss and tapered string parameters along the wellbore will be provided during the concentric dual-tube steam injection for horizontal wells.

Abstract: This paper explains the mechanism of oil well paraffin deposit. The paraffin deposit velocity has a closed relationship with the temperature distribution of the well, the production of the well , and the roughness of pipe. This paper quantitatively calculates the speed of paraffin deposit of oil wells on the basis of certain assumptions, deduces the quantitative calculation method of paraffin removal cycle based on laminar flow model and provides a quantitative basis for determining the oil well paraffin removal cycle on time.

Abstract: Natural gas is generally transported with high pressure, and most of the gas pressure is above 10MPa, which will be 0.4MPa after the vacuum treatment at pressure regulating station. So there is huge pressure energy that can be recovered. The research uses turbo expander instead of throttle valve in the natural gas transport process, which will avoid the threat and damage to the equipment and lower network by the low temperature natural gas. The huge demand for natural gas pipeline in China makes the research of “pressure recovery and cascade utilization of energy in the process of natural gas transportation” to be true. The research can not only avoid the huge waste of pressure in the network, but it can also improve the comprehensive utilization rate of energy, which is of vital importance to our conservation-oriented society today.

Abstract: In ord to solve the hole collapse problem of mud shale in LiaoHe Oilfield,further research and improment of KCl drilling fluid was conducted.and promotion in mine house, two South Beach Sea and other regions, to prove that the strong anti-sloughing drilling fluid system capacity, accident low, Liaohe Oilfield meet the needs of sloughing shale.

Abstract: The homogeneous acidification technology for Horizontal well is developed to solve the problem of serious pollution in near wellbore area owing to long-time mud soak and large contact area of injected fluid. It not only reduces cost, but also improves acidification efficiency and controllability of horizontal wells. Through field experiments, the technology has got great achievements on eliminating well pollution and increasing productivity.

Abstract: SZ 36-1 oilfield has entered high water cut stage, and thus research on the distribution of oil is important for tapping potential in oilfield. In this paper, the distribution of residual oil of SZ 36-1 oilfield was discussed by fine reservoir description and dynamic analysis. The saturation of residual oil at faults, “died oil” between two well, the top of positive rhythm sand body and low (no) permeability interlayer is higher than other situations. We point out that infilling adjustment wells, increasing the oil well productivity and structure adjustment of produced liquid are efficient measures to enhance oil recovery for SZ 36-1 oilfield .