三类油层聚驱油井压裂效果及影响因素分析

喇嘛甸油田三类油层属于薄差油层,以表外储层发育为主。和主力油层相比,具有有效厚度小、非均质性强、渗：匿率低、油层发育薄等特点。但其发育广,储量丰富,地质储量达1．6亿吨,是喇嘛甸油田聚合物驱的主接替潜力层。现场试验表明,三类油层注聚是可行的,并且采取必的压裂措施,能够有效的提高三类油层的动用程度。但现场压裂效果表明,受地质因素影响,不同油井压裂效果存在很大差异。本文以大庆喇嘛甸油田喇8—182井区三类油层注聚试验区为例,通过分析总结不同地质条件油井压裂效果,为进一步提高三类油层聚驱采出程度提供借鉴。     

关于对压裂措施与油井增产之间关系的研究

在油田增产的各种措施中油井压裂是油田重要的增产措施,因此在确保油井增产的同时又要确保提高压裂井质量,保证压裂效果,提高采油效率。本文从油井的地质因素开始分析,针对施工质量和压裂措施进行分析处理,得出改善油井低效生产的方法,增加油田的高效益开发。人工压裂是压裂中采取的一种重要的措施,如果不进行压裂油井产量的下降是不可避免的,由于油井属于不可再生资源,因此在使用的过程中应当尽量采取保护措施,保证油井可以高效长期的使用。     

葡南地区特低渗透扶余油层压裂射孔层位优选与确定

葡南扶余油层砂体分布复杂、含油性变化大、物性参数存在差异,造成油层优选及射孔选层难度大。本文针对2002年投产的葡31试验区压裂射孔方案存在的问题,在葡333-葡462区块进行试验,综合考虑探井及评价井的试油资料、前期压裂试投油井的产液能力、优选主力层等方面,确定了扶余油层压裂射孔的原则。在这一原则指导下编制的压裂射孔方案运用到实际生产中后,收到了很好的效果,不仅确保了油井的初期产能,也为扶余油层的梯次动用和接替稳产奠定了基础,节省了压裂费用。     

关于长庆油田油井区块压裂技术的探讨

压裂技术是长庆油田石油配套技术的重要组成部分,同时也是提高油井区块产量的关键技术,因此在长庆油田油井区块的开发过程中占据着非常重要的地位。近年来,长庆油田油井区块的压裂技术针对不同的油藏条件以及储层形成了一套非常完善的压裂技术模式,为长庆油田油井区块的开发提供了重要技术手段。本文主要对长庆油田油井区块的压裂技术现场进行了分析,并研究了油井区块压裂技术的发展趋势。     

油井压裂施工的风险控制与安全措施

油井压裂是一项比较具有技术含量和难度的作业，因此进行这项作业需要过硬的技术和较高的设备。安全问题也是在油井压裂作业中一个十分重要的问题。若安全问题得不到很好的保障，则会对人员及财产造成极大的损失，也会影响油井压裂的作业质量。油井压裂的风险大，因而，也需要加强其安全的对策和保障措施。油井压裂作业的工作环境恶劣，难度大。一旦发生安全隐患就会给工作带来风险，给工作人员带来很大的损失及伤害。因此，在进行油井压裂之前一定要把安全工作放在第一位，最大限度的排出安全隐患。保证工作的正常安全运行。     

多层段多裂缝压裂工艺技术现场试验

油田开发初期,厚油层的油藏条件优越,单井压裂增油效果显著,压裂改造规模较小。随着油田开发的不断进行,厚油层的油藏条件逐年变差,常规压裂已不能满足多段多韵律厚油层的需要。针对以上问题,开展了多层段多裂缝压裂工艺技术现场试验,扩大改造油层厚度和改造规模,从而提高水驱压裂井挖潜效果。     

低温薄差储层水平井压裂改造技术研究

本文介绍了某油田低温薄差储层水平井双封单卡分段整体压裂技术及其相关配套工艺。通过对葡萄花油层水平井压裂改造技术研究,在人工裂缝形态认识的基础上,对8口井37个层段压裂改造的成功实施,形成了葡萄花油层水平井压裂改造技术,对指导某油田水平井压裂开发具有重要意义。     

浅析油井压裂的风险及安全对策

油井压裂是一项比较具有技术含量和难度的作业,因此进行这项作业需要过硬的技术和较高的设备。安全问题也是在油井压裂作业中一个十分重要的问题。若安全问题得不到很好的保障,则会对人员及财产造成极大的损失,也会影响油井压裂的作业质量。油井压裂的风险大,因而,也需要加强其安全的对策和保障措施。     

浅析油井压裂的风险及安全对策

油井压裂是一项比较具有技术含量和难度的作业,因此进行这项作业需要过硬的技术和较高的设备。安全问题也是在油井压裂作业中一个十分重要的问题。若安全问题得不到很好的保障,则会对人员及财产造成极大的损失,也会影响油井压裂的作业质量。油井压裂的风险大,因而,也需要加强其安全的对策和保障措施。     

葡萄花油田中高含水期油井压裂选井选层方法

随着油田开发的不断深入,葡萄花油田已进入高含水期开采,油井压裂选井选层越来越困难。为了确保油井压裂的经济效益,提高油井压裂方案符合率,根据近年来的压裂选井选层实践,总结了一套适合葡萄花油田的压裂选井选层方法,即应用西帕切夫水驱曲线结合精细地质研究成果指导压裂选井选层的参考方法。经实际应用,取得了较好的效果。     

高能气体压裂过程中压井液运动计算模型研究

针对压井液运动对高能气体压裂作用效果影响较大、现有技术对压井液运动过程研究不足的问题,开展了高能气体压裂过程中压井液运动特性及作用效果研究。按照压井液在高能气体压裂作用过程中的运动过程,分别建立了压井液运动流体压缩阶段、刚体运动阶段及压井液运动能量损耗计算模型;在此基础上,通过计算实例对高能气体压裂过程中的压井液运动及作用效果进行了进一步的分析。结果表明,所建立的描述高能气体压裂过程中压裂火药燃烧时间内的压井液运动计算模型具有较好的合理性和适用性,可以应用到现有的复合射孔高能气体压裂理论计算模型体系中。     

水平井压裂裂缝监测与分析

水平井可以在不太厚的油层中增大钻井过油层范围,实现高速注、采,提高产量 。有些水平井需要压裂,因此常常需要了解并控制人工裂缝形态、方位。通过微地震人工裂缝监测,研究已有的水平井压裂结果,特别是钻井水平段大体沿最大水平主应力方向的水平井压裂,了解压裂裂缝形成的机制及控制方式。通过比较,进一步提高水平井钻井水平及控缝理论。     

Numerical simulation study of shale gas reservoir with stress-dependent fracture conductivity using multiscale discrete fracture network model

The exploitation of shale gas has increasingly become the focus of worldwide energy industry. Due to the existence of natural/hydraulic fractures, most of the shale gas reservoirs exhibit high degree of heterogeneity and complexity which leads to the stress-dependent fracture conductivity of shale gas reservoir. Discrete fracture network (DFN) model is adopted in this research since the conventional continuum model cannot meet the numerical simulation requirements of fractured shale gas reservoir. A series of experiments about the fracture properties stress-dependent have been conducted on some shale core samples, the stress-dependent fracture conductivity correlation is selected and incorporated into the mathematical model to characterize the reduction of fracture conductivity potential with the reservoir pressure drop. The DFN model is applied to a shale gas reservoir with fracture network to study the effect of the stress-dependent fracture conductivity on the shale gas well performance. The results show that the effect of fracture conductivity reduction with pressure drop on the shale gas well performance depends on both the initial fracture conductivity and matrix permeability. The complex interactions between the fracture and matrix permeability should be considered when select the appropriate size of proppants for fracturing.     

Equivalence between stress intensity factor and energy approach based fracture parameters of concrete

The paper presents numerical study and relationship between the double-K fracture parameters and the double-G fracture parameters using two standard tests. The data required for calculation is obtained using cohesive crack model. It is observed that both the corresponding parameters of the double-K fracture model and the double-G fracture model at the onset of crack initiation and unstable fracture are equivalent. This observation agrees well with experimental results available in literature. It is also found that the fracture parameters of double-K fracture criterion and double-G fracture criterion are influenced by initial notch-length/depth ratio, specimen shape, size and softening function.     

T应力对Ⅰ-Ⅱ复合型裂纹扩展的影响

利用最大周向正应力判据MTS重新分析研究了脆性破坏的Ⅰ-Ⅱ复合型裂纹扩展,其中考虑了平行于裂纹方向的非奇异项T应力。以平板中的斜裂纹处于双向受力为研究对象,通过两个方向力的不同组合以及裂纹与受力方向的夹角变换得到包括纯I型和纯II型在内的Ⅰ-Ⅱ复合型裂纹,分析了T应力对裂纹扩展方向以及断裂时的应力强度因子的影响,并将预测结果与现有的实验数据进行了比较。在此基础上,给出了不同T应力条件下通用的Ⅰ-Ⅱ复合型裂纹扩展条件,可用于给定几何试件的脆性断裂判定。分析结果表明:裂纹尖端非奇异项T应力对裂纹扩展的影响是不可忽略的,尤其是对II型断裂的影响更为明显。     

Newtonian fluid flow from an arbitrarily-oriented fracture into a single sink

Summary A model of fluid flow from an arbitrarily-oriented compressible fracture into a sink has been developed. Effects of fracture inclination, fracture dimensions, in-plane aspect ratio, fracture compressibility, sink location, sink pressure, initial equilibrium pressure inside the fracture and fracture wall roughness on fluid flow into the sink have been investigated. It has been found that the effect of fracture inclination decreases with decreasing fracture compressibility. Sink location (in the middle of the fracture, at the edge, or in the corner) has a significant effect on the fluid flow into the sink. Fluid flow into the sink is shown to be controlled mainly by the difference between the initial fluid pressure in the fracture and the sink pressure, but not by the absolute values of these parameters. The effect of the fracture wall roughness was investigated using fractures with artificial surfaces having Hurst exponent of 0.5. In case of a widely-opened fracture, the effect of roughness is negligible, and the fracture can be approximated with a smooth-walled fracture of the same mean aperture. In case of a partially-closed rough-walled fracture, the roughness was found to affect the flow rate significantly by extending the discharge time. This has an important implication for oil production from certain types of naturally-fractured reservoirs. The roughness of partially-closed fractures did not, however, affect the results of the comparative parametric study, which justified the use of a simplified smooth-wall model in such studies. Modeling results have implications for the simulation and analysis of some drilling situations in fractured rocks as well as for well testing analysis and oil production simulation.     

Interfacial bonding and the toughness of carbon fibre reinforced glass and glass-ceramics

The work of fracture of four different carbon fibre reinforced glass and glass-ceramic composites has been measured to determine the effects of the different properties of the components on fracture behaviour. Differences in fracture energies can be explained in terms of the fibre pull-out model and differences in the fibre-matrix interfacial shear bond. The work of fracture of the glass-ceramic is independent of crack velocity while that of the Pyrex matrix composite decreases with increasing velocity at low velocities, the decrease stopping at higher velocities. Work of fracture values agree well with linear elastic fracture mechanics toughness values.     

Numerical prediction on dynamic fracture of tubes subjected to internal gaseous detonation

Gaseous detonation-driven fracture is a strongly coupled fluid-structure-fracture problem which involves fluid motion, chemical reaction as well as structural large deformation and fracture. In our work, a stability-based coupling approach which couples a Lagrangian structure solver with fracture capability and an Eulerian fluid solver with detonation computation capability was developed to achieve the fluid-structure interaction (FSI) simulation of tube fracture due to internal gaseous detonation. Different from an assumed fracture strain or stress, a rate-dependent failure criterion for metal materials at high strain rate conditions was employed in the simulation to account for the failure of the tubes. The interaction between detonation wave and tube, dynamic crack propagations, strain responses, crack speeds and the venting of detonation products were obtained and discussed. The simulated final fracture patterns were compared with experiments and the numerical results from other literatures. It is found that our approach reproduces the experimental crack propagations quite well, and it gives a more reliable prediction of the fracture patterns of tubes subjected to gaseous detonation loads compared with other literatures.     

高密度硬质聚氨酯泡沫塑料的断裂特性

制备不同密度的硬质泡沫聚氨酯塑料,实验研究了材料的拉伸和冲击性能。断口的扫描电镜现察显示,材料的断裂基本上属于脆性断裂,但局部存在明显的塑性形变,这是与材料的有机大分子的特殊结构相关。材料的断裂原因在于材料中相邻泡体互通构成的结构缺陷．根据断裂力学的一般原理。确定了材料断裂韧性的预测的可行方法。并得到实验结果的验证。     

Cracking due to multiple indentations in silicon: effect of indentation spacing and relative orientations

The issue of multiple cracks in materials and their interaction is central in understanding the overall fracture behavior of materials. In the case of materials used in the microelectronics industry, indentation cracking has been extensively used for the measurement of fracture toughness due to its small sample size requirements as well as a relatively good correlation with values obtained from traditional fracture mechanics tests. The majority of these studies have focused on the fracture behavior of a single indent. The present study was aimed at understanding the effect of interaction between the cracks generated on Si from a pair of sequential indents as well as a set of four sequential indents placed at the corners of a square. The distance between the indents was varied from a level comparable to the crack size to a level where interaction could be ignored. This paper discusses the changes in the nature as well as the sizes of cracks due to interaction between the stress fields of the indents.