MP PFGun脉冲爆燃压裂技术在阿曼SSM-XX井的应用

简要叙述了MP PFGun技术工作原理、系统结构特点以及PropFrac脉冲压裂模拟器软件基本功能,并对SSM-XX井的模拟计算P-T曲线和井下压力仪实测曲线进行了对比。结果表明:SM-XX井采用MP PFGun电缆输送工艺安全,脉冲压裂持续时间长,且利用PropFrac模拟软件指导施工设计,取得了较好的应用效果。     

Evidence of fluid evolution of Baoshan Cu−Pb−Zn polymetallic deposit: Constraints from in-situ sulfur isotope and trace element compositions of pyrite

In-situ LA-ICP-MS and S isotopes of pyrite from the Baoshan Cu polymetallic deposit were conducted to investigate the ore-forming process and the enrichment mechanism of elements. Three generations of pyrite (Py I, Py II, and Py III) in the skarn-type ores and pyrite in the carbonate-hosted sulfide ores from central, western, and northern (C_Py, W_Py, and N_Py) mining districts are selected for comparison. Compared with Py I and Py III, the contents of most elements in Py II are apparently higher. The As and Se contents are high within a wide range and are decoupled in the growth band of the C_Py. The highest As, Se, and Pb contents were found in W_Py and N_Py. These results indicate the drastic changes in the temperature and fluid mixing during the mineralization. The occurrence of fluctuation and change in temperature and f(O₂) was triggered by intermittent pulses of magmatic-hydrothermal fluids, mixing with meteoric water, and water−rock interactions. The sulfur isotopes of all species of pyrite indicated the magmatic source. The change in the f(O₂) conditions caused slight differences in the sulfur isotope compositions. Consequently, a metallogenic model was proposed to explain the ore-forming processes.     

压裂水平井产能预测方法研究进展

水平井压裂技术在低渗透及非常规储层中得到了广泛应用,压裂后水平井的产能预测关系到油田开发方案的制定,因此,国内外学者对压后渗流模型的建立和求解方法做出了不懈的努力。本文详细回顾了国内外学者所建压裂水平井产能预测模型及求解方法,指出了不同模型和求解方法的优缺点,并展望了压裂水平井产能模型的发展方向。     

压裂管汇无损检测方法改进

:按照现有无损探伤检验标准检验合格的压裂管汇在压裂作业时出现了管件刺漏、爆裂等情况。分析了压裂管汇中管件结构的特点和现有的无损检测方法的适用性。增加了管件的检测部位,改进了检测方法,并研制出了能检测不同形状和尺寸管件的超声波探头和比对试件。采用改进的无损检测方法,检测出不合格管件数增加44.9%。新增加检测部位后,检测出不合格管件数增加63.7%。目前已应用改进的无损检测方法1 a多,在压裂作业时未出现高压管件刺漏或爆裂情况。     

An innovative technology of directional propagation of hydraulic fracture guided by radial holes in fossil hydrogen energy development

Conventional hydraulic fracturing fails to develop low permeability reservoirs of fossil hydrogen energy that are not located in the direction of maximum principal in-situ stress. A new technology of fracture propagation guided by radial holes is proposed, which can realize directional propagation of hydraulic fracture along radial holes in fossil hydrogen energy development. In order to verify this new technology, a model of radial holes combined with hydraulic fracturing is established by the ABAQUS extended finite element method. Simulation results show that radial holes play a guiding role in fractures propagation. The influence extent of seven factors on the directional propagation of hydraulic fracture is listed as follows (from strong to weak): azimuth of radial holes > horizontal in-situ stress difference of fossil hydrogen reservoir > injection rate of fracturing fluid > Young's modulus of rock > permeability of fossil hydrogen reservoir > Poisson ratio of rock > viscosity of fracturing fluid. True tri-axial experiment is carried out to verify the accuracy of numerical simulation, and the result is consistent with numerical model, which indicates that numerical simulation is reliable.     

Rock brittleness indices and their applications to different fields of rock engineering:A review

Brittleness is an important parameter controlling the mechanical behavior and failure characteristics of rocks under loading and unloading conditions,such as fracability,cutability,drillability and rockburst proneness.As such,it is of high practical value to correctly evaluate rock brittleness.However,the definition and measurement method of rock brittleness have been very diverse and not yet been standardized.In this paper,the definitions of rock brittleness are firstly reviewed,and several representative definitions of rock brittleness are identified and briefly discussed.The development and role of rock brittleness in different fields of rock engineering are also studied.Eighty brittleness indices publicly available in rock mechanics literature are compiled,and the measurement method,applicability and limitations of some indices are discussed.The results show that(1)the large number of brittleness indices and brittleness definitions is attributed to the different foci on the rock behavior when it breaks;(2)indices developed in one field usually are not directly applicable to other fields;and(3)the term“brittleness”is sometimes misused,and many empirically-obtained brittleness indices,which lack theoretical basis,fail to truly reflect rock brittleness.On the basis of this review,three measurement methods are identified,i.e.(1)elastic deformation before fracture,(2)shape of post-peak stressestrain curves,and(3)methods based on fracture mechanics theory,which have the potential to be further refined and unified to become the standard measurement methods of rock brittleness.It is highly beneficial for the rock mechanics community to develop a robust definition of rock brittleness.This study will undoubtedly provide a comprehensive timely reference for selecting an appropriate brittleness index for their applications,and will also pave the way for the development of a standard definition and measurement method of rock brittleness in the long term.     

水平裂缝对坚硬顶板失稳破断的影响规律研究

为了研究水力压裂形成水平裂缝后坚硬顶板的失稳破断规律,基于材料力学和关键层相关理论,结合数值模拟,对含水平裂缝坚硬顶板的变形破坏特征和失稳破断机制进行了研究。结果表明:当坚硬顶板存在水平贯穿裂缝时,无论上位与下位岩层是否发生同步运动,坚硬顶板的破断步距均小于其初始极限跨距。存在水平贯穿裂缝的坚硬顶板及其上覆岩层,会形成拉压复合破坏区,更易于发生失稳破坏。坚硬顶板块体咬合点区域的拉压复合破坏作用是造成块体局部失稳、回转加剧和整体破断的主要原因。     

碎软煤层条带瓦斯地面高效抽采技术研究

为了提高碎软煤层条带瓦斯抽采效率和效果,基于目前地面瓦斯抽采主要采用垂直井或从式井的方式抽采效果差、效率低的现状,通过理论和实验分析论证了穿岩层压裂改造煤储层的可行性,提出了在目标煤层顶板岩层中钻水平井,并通过垂直向下射孔以及采用泵送桥塞分段进行压裂的方式进行地面瓦斯抽采。试验结果表明:顶板分段压裂水平井单井产量高、高稳产期更长、产量衰减更慢;有效水平井段控制区域内瓦斯下降均匀,更有利于进行条带瓦斯抽采;相同投资条件下,采用水平井的方式瓦斯抽采效率和投入产出比更高。     

定向长钻孔整体水力压裂增透技术在赵固二矿的应用

针对赵固二矿煤层透气性低、钻孔有效影响半径小，实施定向长钻孔代替底板岩巷进行区域瓦斯治理期间钻孔工程量大、瓦斯抽采效果不理想的问题。结合煤层赋存特征及钻孔施工情况，采用定向长钻孔整体水力压裂增透技术，理论分析了合理坐封位置、压裂参数，完成200 m煤巷条带一次整体压裂，最大泵注压力24.3 MPa、累计注水量1 613 m³。并基于煤层全水分变化，考察确定了单个钻孔压裂影响范围达到巷道两帮30 m，有效改善了煤体储层特性，提高了煤层瓦斯抽采效率。在实现定向钻孔对预抽煤巷条带可靠控制的同时，最大程度降低了钻孔工程量、缩短了瓦斯治理周期，为实现矿区“以孔代巷”及高效安全开采提供了技术支撑。     

水平井分段体积压裂复杂裂缝形成机制研究现状与发展趋势

水平井分段体积压裂是油气储层中复杂裂缝网络形成的重要技术之一，准确了解复杂裂缝网络形成机制、预测复杂裂缝网络形态对非常规油气资源高效开发具有重要意义，同时也是水力压裂设计优化的理论基础。围绕非常规储层复杂裂缝形成机制，国内外学者根据"应力阴影"效应对水力裂缝同步扩展、水力压裂顺序对多裂缝动态延伸影响、层理面对水力裂缝纵向扩展遮挡效应和天然裂缝与水力裂缝交互动态等方面，分别建立了相应的水力压裂模型，并从数值模拟角度对其进行了定性分析。通过总结国内外研究现状，并从模型建立假设条件、数值模拟模型思想和模型局限性3方面对现有模型进行了剖析，并对未来研究方向提出了建议，研究结果可对未来水力压裂复杂裂缝形成机制研究提供借鉴。