全文获取类型
| 收费全文 | 202篇 |
| 免费 | 4篇 |
| 国内免费 | 1篇 |
专业分类
| 电工技术 | 9篇 |
| 综合类 | 14篇 |
| 化学工业 | 19篇 |
| 金属工艺 | 3篇 |
| 机械仪表 | 11篇 |
| 建筑科学 | 12篇 |
| 矿业工程 | 2篇 |
| 能源动力 | 19篇 |
| 轻工业 | 2篇 |
| 水利工程 | 1篇 |
| 石油天然气 | 54篇 |
| 武器工业 | 2篇 |
| 无线电 | 5篇 |
| 一般工业技术 | 37篇 |
| 冶金工业 | 4篇 |
| 原子能技术 | 2篇 |
| 自动化技术 | 11篇 |
出版年
| 2024年 | 1篇 |
| 2023年 | 3篇 |
| 2022年 | 3篇 |
| 2021年 | 3篇 |
| 2020年 | 4篇 |
| 2019年 | 10篇 |
| 2018年 | 2篇 |
| 2017年 | 3篇 |
| 2016年 | 5篇 |
| 2015年 | 8篇 |
| 2014年 | 11篇 |
| 2013年 | 10篇 |
| 2012年 | 11篇 |
| 2011年 | 18篇 |
| 2010年 | 14篇 |
| 2009年 | 13篇 |
| 2008年 | 15篇 |
| 2007年 | 16篇 |
| 2006年 | 6篇 |
| 2005年 | 8篇 |
| 2004年 | 5篇 |
| 2003年 | 5篇 |
| 2002年 | 4篇 |
| 2001年 | 4篇 |
| 2000年 | 3篇 |
| 1999年 | 7篇 |
| 1998年 | 4篇 |
| 1997年 | 1篇 |
| 1996年 | 2篇 |
| 1995年 | 2篇 |
| 1994年 | 1篇 |
| 1993年 | 2篇 |
| 1992年 | 1篇 |
| 1991年 | 2篇 |
排序方式： 共有207条查询结果，搜索用时 15 毫秒
121.
The in-plane perforation is a new type of well completion method for the stimulated reservoir volume (SRV) of tight oil and gas reservoirs. Previously, however, the regulatory effects of perforation on fracture initiation position and fracture geometry near the wellbore were less studied, the spatial position of each channel of in-plane perforation was simplified as a plane, and the effects of the angle parameters of in-plane perforation on the fracturing pressure of a horizontal well and the fracture geometry near the wellbore were neglected. In order to make up for these shortcomings, a near-wellbore fracture mechanics model in the form of hydro-mechanical coupling was established in this paper. Then, local 3D fracture initiation position and geometric change of shots were characterized by using the fracture element based on continuous damage mechanics, and the finite-element numerical solving program of a coupling model was developed to investigate fracture initiation and propagation laws. Finally, the effects of perforation angle and departure angle on the initial fracturing pressure and fracture initiation position were analyzed quantitatively based on the actual perforation completion parameters of horizontal wells in the Changqing Oilfield. What's more, the fracture geometry near the wellbore of horizontal wells with in-plane perforation was compared with that with helical perforation. And the following research results were obtained. First, the fracturing pressure and fracture initiation position of the horizontal wells with controllable perforation vary with perforation angle and departure angle. The fracturing pressure of channel varies greatly, and fracture initiation occurs at different positions, e.g. the perforation—wellbore interface and the middle part of the channel. The in-plane perforator shall control the departure angle in the range of 15°–30°. Second, by changing the jet direction of channels, in-plane perforation increases the stress interference between the channels, so as to reduce the fracturing pressure of horizontal wells by 2.0–3.5 MPa. Third, the in-plane perforation can guide and control the fracture strike near the wellbore, so as to produce the initial fracture plane perpendicular to the wellbore of horizontal wells and avoid the distortion of near-wellbore fractures caused by helical perforation. In this way, the completion degree of the fracture the system near the wellbore of a horizontal well is improved. In conclusion, the near-wellbore fracture mechanics model established in this paper can simulate the perforation and near-wellbore dynamic fracture process of a horizontal well, and its calculation results are better accordant with the field test data. 相似文献
122.
Guoqiang Tang;Dong Xu;Baosheng Zhang 《天然气工业》2019,39(06)
China issued in 2017 Some Opinions on Deepening Reform of Petroleum and Natural Gas System. Subsequently, relevant ministries successively issued a series of new policies on oil and gas related reform, one of which is that the marketization process of oil and gas exploration and development is encouraged to be accelerated. Under the background of oil and gas system reform, it is of great practical significance to study the assignment mechanism among those state-owned giant oil and gas enterprises. Therefore, combined with the main practices of mineral rights management in other countries and the assignment of mineral rights of international oil companies, based on China's oil and gas mineral rights assignment policy, competitive assignment and assignment practices, the basic ideas and mechanisms for the assignment of mineral rights of giant state-owned oil and gas enterprises were proposed as follows. (1) Follow the guiding ideology of hierarchical classification and phasing, and generally adhere to the principles of marketization and of "four categories, three methods & two stages" in the design of the framework of mineral right assignment. (2) Set up a mineral rights management leading group as well as specialized risk exploration companies, improve the decision-making mechanism for the assignment of mineral rights, and complete the management of the assignment of mineral rights. (3) Continue to strengthen the protection and internal assignment of mineral rights in Classes I and II blocks. In the short term, it is necessary to strengthen special investment in key guarantee blocks, continue to promote internal assignment, and innovate exploration and unused reserves project management system and mechanism, innovate the cooperation mechanism of Party A and Party B. In the long term, it is necessary to explore effective mineral rights management system, establish a linkage mechanism for mineral rights protection and assignment, and foster a competitive and competitive internal mineral rights market. (4) Appropriately increase the proportion of cooperative exploration and development of mineral rights joint venture and cooperation of Class III blocks, and focus on offshore and deep-water cooperative exploration and development projects. (5) Gradually explore the external competitive assignment of Class IV blocks, expand the scope of assignment in light of the progress of national qualification approval in the short run, and realize market-oriented competitive assignment in the long run. 相似文献
123.
储集层被打开后,由于原地应力平衡被破坏,井孔周围的应力将重新分布。如果储集层胶结强度较低,近井带存在较大范围的塑性区。由于存在塑性区,以及钻井过程中发生钻井液的滤液及固相颗粒侵入,此双重作用导致近井带的渗透率很低,分成具有不同渗透率的３个带（含塑性作用的损害带,塑性带,弹性带）。由于塑性带宽度较大,其渗透率比弹性带小得多,因此在确定射孔深度时应将塑性带考虑在内。进行了近井周围储集层的弹塑性分析,给出了塑性带半径的计算方法,分析了影响塑性带范围的因素,在此基础上指出：射孔的最小深度应包括塑性带宽度。图３参７（段玉廷摘） 相似文献
124.
针对某公司卧式列管换热器的腐蚀穿孔问题,对失效的换热器进行了宏观形貌、微观形貌、腐蚀产物能谱、金相组织及材料化学成分等分析,结果表明,这是一起由厌氧的硫酸盐还原菌引起的微生物腐蚀。并从中得到几点启示,可为今后解决此类问题提供参考。 相似文献
125.
投球压裂曲线分析及压开层位的判定计算 总被引：4，自引：0，他引：4
利用孔眼摩阻公式分析了投球压裂曲线的瞬时停泵时的压降落差以及投球压裂中投球所造成的压力上升的幅度,并建立了相应的关系式,可以计算投球是否压开新层以及压开的层位。此方法在新疆鄯善等油田得到了应用,其计算结果与压裂后井温,压裂后产液剖面测试结果及层间布孔匹配吻合得很好。 相似文献
126.
����QK17-2��λ��ˮƽ��TCP�����ʵ�� 总被引：1，自引：0，他引：1
文章介绍国家 863项目 82 0 - 0 9海底大位移钻井技术 ,在渤海QK1 7- 2项目中 ,成功地在大位移水平井完井中应用TCP射孔技术的情况 ,该项目在最大井深 4 690m ,最大井斜 86° ,最大水平位移 3 697m ,射孔段长近 10 0 0m的情况下 ,经过项目组潜心研究 ,并且对油藏保护 ,射孔液 ,射孔工艺 ,作业方案等问题进行了严格评价、反复论证和精心筛选 ,使用了模拟射孔管柱下入精细校深技术 ,水平井仪器下入工具的泵送技术 ,正压差长井段射孔技术 ,井下压力延迟点火技术等四大技术 ,同时在实践中还总结和摸索出了一套作业方法并且初步形成了一套大位移水平井现场作业技术集成 ,在射孔压差选择、防止地层出砂 ,一次射孔井段长度确定 ,保证射孔枪起枪安全措施等方面取得了成功经验 ,保证了国家 863项目任务的圆满完成 ,同时也为大位移水平井进行TCP射孔作业提供了值得借鉴的经验 ,并且为今后进一步完善和发展我国海洋大位移水平井钻完井技术 ,奠定了坚实的基础 相似文献
127.
Homogeneous charge compression ignition (HCCI) combustion in diesel engines offers the potential of simultaneous low NOx and soot emissions. However, this is normally accompanied by high hydrocarbon (HC) levels in the exhaust and an early combustion phasing before the top‐dead‐center (TDC) that may drain out substantial amounts of fuel energy from the engine cycle. Exhaust gas recirculation is usually applied to delay the onset of combustion, thereby shifting the phasing of the heat release close to the TDC. Although the retarded phasing improves the engine energy efficiency, a significant increase in HC and carbon monoxide emissions will deteriorate the combustion efficiency. Therefore, an inherent trade‐off exists between the combustion phasing and the combustion efficiency that needs to be minimized for improved energy efficiency. In this work, both theoretical and experimental studies have been carried out to evaluate the combustion efficiency‐phasing (CEP) trade‐off. Engine tests have been conducted to analyze the losses in combustion (burning) and phasing efficiencies, and along with theoretical analyses, the CEP trade‐off has been evaluated in terms of a ‘coefficient of combustion inefficiency’ (CCI). The CCI quantitatively correlates the losses in combustion and phasing efficiencies and provides a reference for improving the combustion phasing of the HCCI operation vis‐à‐vis the combustibles in the exhaust. The focus of this research is to carry out a quantitative analysis of the energy efficiency of HCCI cycles. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
128.
国内现行的射孔作业计价方法存在着适应性差、可操作性不强等缺陷,不能满足射孔新技术发展的要求和射孔业务市场化定价的需求。为此,分析研究了国内外射孔作业现行的\"标准炮\"\"射孔米\"\"固定费+深度费+作业费\"\"深度费+材料费\"4种计价方法的优缺点;结合射孔工程施工工艺特点和新技术发展趋势,提出了\"深度米+射孔米\"的计价方法。该计价方法以工程量清单计价方法为原则,采用深度米、射孔米、孔密度系数和价格系数等4项关键技术参数,形成了一套可操作性强的射孔计价方法体系。射孔新计价方法主要具有以下优点:①采用射孔米计费能够满足不同射孔方式下的直接消耗,通过孔密度系数和价格系数反映不同工艺和市场价格变化情况,具有科学性;②采用深度米计费反映出不同井深条件下的消耗差异;③射孔价格编制简单,费用计算简便,实用性强;④工程量能够准确计量,相应价格具有可比性,能够适应未来工程量清单计价的发展要求。 相似文献
129.
ˮ�����ɰ��������ײ�λ�Ż���ʵ�÷��� 总被引：6，自引：3，他引：3
水驱多层气藏采用多层合采方式进行开采,是减少开发井网、井数,提高单井产量,防止气井出砂,从而实现气田高效开发的有效途径。但若层间互不连通,由于各气层气水边界及驱动能量不尽相同,在多层合采时,边水推进速度不一致,某单层的提前见水将导致全井产量和压力大幅度下降,甚至可能导致气井关闭。因此,此类气田一般采用射孔层段优化来保证射孔单元内各气藏（层）的边水能够均匀推进,使气井具有较高的产量和较长的稳产时间,从而提高气田采收率。文章利用物质平衡原理推导出此类气田射孔层位优化的一种实用方法,通过优化气层在平面上的射孔井网、井数和纵向上的打开程度,使同一射孔单元内各层保持相同或相近的采气速度,可达到射孔层位优化的目的。该方法在青海涩北气田得到应用,提高了气田单井产量,并对气田稳产和提高采收率有积极意义。 相似文献
130.
管道作为大量输送石油、水、气体等介质的最为安全经济的方法在油田得到广泛应用,而输送油、气的管道大多处于复杂的土壤环境中,所输送的介质也多有腐蚀性,因而管道内壁和外壁都可能遭到腐蚀.据统计,采油九厂在2008、2009年平均每年更换腐蚀老化管线10.25 km,而在2010年更换腐蚀老化管线达到了15.195 km,可以说管线腐蚀问题,已经严重的影响到油田的正常生产.本文对龙虎泡油田腐蚀管线的成因进行分析并对采油九厂阴极保护实施效果进行评价,得出了外围油田埋地金属管道腐蚀穿孔的主要原因,并提出了相应的腐蚀穿孔控制建议,为管道安全输送提供技术保障. 相似文献