裂缝性低渗透油藏开发方案研究

裂缝性低渗透油藏在我国石油工业中占有十分重要的地位,如何实现这类油藏的经济、高效开发是石油部门的重要课题.根据裂缝性低渗透的渗流特征和裂缝分布特点,建立了裂缝性低渗透油藏渗流等效连续介质模型,编制了相应的裂缝性低渗透油藏数值模拟软件.利用该软件对两井油田让11区块进行了模拟,分析了不同注采方式、不同井距下的各方案的驱油效果和经济评价指标,优选出适合于该模拟区块的开发方案.计算结果表明,矩形井网最适合低渗透油藏,且井距取250 m时各项经济指标最优.可为裂缝性低渗透油藏开发方案的优化提供参考.     

低渗透裂缝性煤层气储层压力敏感性研究

近年来,随着煤层气开采技术的进一步发展,国内煤层气开发已具有一定规模.由于煤层气储层具有低渗透裂缝性的特征,压力敏感性强,导致钻井过程中容易造成储层损害.因此,开展低渗透裂缝性煤层气储层的压力敏感性研究具有重要的意义.结合山西沁水盆地某区块的煤心,分别开展了煤岩受围压和孔隙压力条件下的压力敏感性实验研究,分析了煤岩渗透...     

A method of calculating the concentration of deposit around an injection well

From the equations analogous to the Herzig-Leclerc-Le Goff equations an inequality is derived. This inequality can be used for calculating the concentration of deposit around an injection well. The full balance equation for solid particles and the kinetic equation in the general form are taken into consideration. The maximum relative error of the method is calculated. The deep radial filtration through the uniform and non-uniform porous media is considered.     

控制姬塬地区长4+5超低渗油藏单井产能的主要地质因素分析

目前针对超低渗油藏单井产能的地质因素分析极少。文章通过姬塬地区长4+5超低渗油层组为研究目的层,以岩芯分析、测井解释数据统计、粒度分析资料、储层宏微观表征等技术手段,对影响目的层位的主要地质因素进行分析。结果表明,研究区目的层单井产能受沉积相类型、储层类型、储层微观参数与有效厚度等多种地质因素控制。具体表现在水下分流河道、前缘席状砂等以砂岩含量居多的沉积微相对应层位单井产能较高;储层内孔隙的空间组合类型、孔渗参数大小均影响储层的渗透与流通程度,从而影响其单井产能。总结不同地质因素对姬塬地区长4+5超低渗油藏的控制作用,可以为研究区今后的布井开发,或进一步的方案调整提供有利的依据。     

一种确定大直径扩底桩极限荷载的新方法

分析了大直径扩底桩的变形性状及扩径比对承载力的影响。对Charles提出的破坏准则进行改进,增加扩底比的影响,得到了确定大直径扩底桩极限承载力的方法。最后采用了5组大直径扩底桩的试验数据,对新方法的适用性进行验证,结果表明对于端承于土层的大直径扩底桩,该方法是有效的。     

New method for determining the elastic parameters of rock mass layers in the region of underground mining influence

The primary objective of the following paper is to determine the value of strata elastic parameters in a selected Polish mining area using a new method based on finite element analysis, GSI geotechnical classification and “back analysis”. The individual rock layer strain parameters were estimated by means of comparing the measured subsidence trough with the result of numerical analysis carried out for the same geological and mining conditions. As a result of such an analysis, the values of the elastic modulus of the anisotropic model of strata were obtained in the region of underground mining influence.     

The applicability of Darcy''s law in determining the water permeability of geotextiles

Water conductivity characteristics of geotextiles are mostly given as a permeability coefficient or as a permittivity value. This is only valid in case of laminar flow. Theories and models, developed to describe flow through porous media and geotextiles in order to delineate the laminar flow zone for which Darcy's law can be applied, are treated and discussed. These models are not suitable to delimit the laminar flow zone because some parameters are difficult to define. Measurements of discharges for a range of hydraulic losses allow the flow regime to be determined. In most cases there is no laminar flow and the calculated permeability values are not exact. Therefore, the water conductivity characteristic of geotextiles is better expressed asa discharge for a given hydraulic loss.     

基于微元法的低渗透储层定向射孔转向压裂裂缝动态扩展模型

为明确低渗透非常规油气储层定向射孔转向压裂改造过程中裂缝扩展轨迹及其偏转距离的变化规律,综合考虑水平地应力差、射孔参数、注液参数、地层力学参数等因素对水力裂缝偏转扩展的影响,建立基于微元法的定向射孔转向压裂裂缝动态扩展模型(MEM模型)。该模型通过VisualBasic语言编制的迭代运算程序完成缝尖微小步长增量与偏转角之间的循环迭代计算,实现对转向裂缝动态扩展过程的模拟。通过比较MEM模型计算的裂缝扩展轨迹与现场压裂微地震监测结果、XFEM模型计算结果及室内压裂试验结果之间的差异,验证MEM模型的准确性。以临兴区块石盒子组致密砂岩储层为例,研究各因素对裂缝扩展轨迹及其偏转距离的影响规律与机制。研究结果表明:不同因素下裂缝扩展轨迹的变化趋势基本一致,裂缝从射孔端起裂后逐渐向水平最大地应力方向偏转,偏转幅度先增大后减小;裂缝偏转距离随水平地应力差的增加呈负对数规律减小,随射孔方位角、注液速率及压裂液黏度的增加呈线性规律增大;射孔长度对裂缝偏转距离几乎没有影响。该模型和结论对进一步认识定向射孔转向压裂过程具有重要意义。     

A simple manifold flow injection analysis for determining phosphorus in the presence of arsenate

A simple manifold flow injection analysis (FIA) for determining phosphorus in the presence of arsenate in water, by the on-line reduction of As(V) to As(III) using sodium sulfite. The FIA method is applicable for the determination of phosphorus in water samples containing less than 0.37 μg·mL^?1 of AsO₄ ^3?. A solution obtained by mixing 6.30 g of Na₂ SO₃ (1 M), 5.0 ml H₂SO₄ 18 M completed up to 50 ml with deionized distilled water was used to reduce on line As(V) to As(III), using a reactor of 0.30 m. The limit of detection is 0.05584 ± 0.00167 μg·mL^?1 P-PO₄ ^3? and sampling frequency is 45 samples per hour. It is a simple and low cost methodology, easily applicable in the determination of phosphorus in samples of water contaminated with arsenate.