12V190型柴油机节油装置应用研究

12V190型柴油机节油装置能够将普通燃油变成纳米级燃油,为油耗管理提供一种有效的信息管理手段。使用该装置可以实现综合节省燃油10%~30%,净化尾气50%~90%。     

12V190ZDT—2型天然气发动机

<正> 为充分利用天然气资源,以气代油,以气换电,我厂在12V190B型柴油机基础上开发研制成功了12V190ZDT—2型天然气发动机。该型机与12V190B型柴油机通用化程度比较高,通用件种数、系数达到83.42％。该型机主要作为电站动力,也可作为油气集输设施或其它方面的动力,如配发电机组、天然气压缩机及油气输送泵等。现已用该型机成功     

Calculation analysis of sustained casing pressure in gas wells

Sustained casing pressure (SCP) in gas wells brings a serious threat to worker safety and environmental protection. According to geological conditions, wellbore structure and cement data of gas wells in the Sichuan-Chongqing region, China, the position, time, environmental condition and the value of SCP have been analyzed. On this basis, the shape of the pressure bleed-down plot and pressure buildup plot were diagnosed and the mechanism of SCP has been clarified. Based on generalized annular Darcy percolation theory and gas-liquid two-phase fluid dynamics theory, a coupled mathematical model of gas migration in a cemented annulus with a mud column above the cement has been developed. The volume of gas migrated in the annulus and the value of SCP changing with time in a gas well in Sichuan have been calculated by this model. Calculation results coincided well with the actual field data, which provide some reference for the following security evaluation and solution measures of SCP.     

凝析气藏合理生产压差的确定

鉴于反凝析油在近井地带的聚集引起产能损失的问题,在制定凝析气井工作制度时,通常以控制生产压差为主,往往忽略高速流动下凝析气液相变的非平衡特征与毛管数效应.为此,分析了凝析气非平衡相变与向井流规律,评价了凝析气在流动过程中的非平衡相变特征和毛管数效应,阐述了凝析液聚集的变化规律.结果表明,流体在高速流动条件下,增强高速流动效应有利于提高凝析气井产能.在对产能预测结果对比的基础上,提出了以凝析液饱和度分布控制为主的凝析气藏合理生产压差确定方法.     

渝东南常压与高压页岩气典型差异性分析及效益开发对策

渝东南地区处于四川盆地东南缘的盆缘转换带,发育常压、高压两种类型页岩气藏。为提高常压页岩气开发效益,从常压与高压页岩气典型差异性分析入手,通过开展钻井、岩心观察、实验分析、成藏条件及生产动态等研究,结合渝东南地区页岩气勘探开发实践,明确了常压页岩气具有优质页岩厚度较薄、孔隙度较低、保存条件较差、含气量中等的典型地质特点。常压页岩气富集受沉积相带、保存条件及地应力场控制,受多期构造改造及差异性抬升影响,形成机理复杂,具有初产较低、稳产期短、递减较慢、返排率高的生产特征。与高压页岩气在地质特点、富集规律、形成机理及生产规律等方面具有明显的地质特征差异性。针对渝东南地区常压页岩气资源品位较差的问题,提出了常压页岩气效益开发的4个关键对策：(1)深化基础地质研究,明确富集规律和甜点目标;(2)建立变井距、长水平段、小夹角、强改造、低高差、控压差的开发技术政策,提高单井产量;(3)加大低成本钻井和高效压裂等工程工艺创新,实现提速提效降本;(4)创新体制机制建设,打造高效组织运行模式。4个关键对策有效促进了常压页岩气由资源向储量、从储量向效益的转变,助力渝东南常压页岩气实现规模效益开发。     

高压气井钻进过程中控制回压值研究

对于高压气井特别是含硫气井安全钻井的控制回压值确定,目前还没有明确结论。文中以漂移流动理论为基础,建立了高压气井带回压井筒气液两相流动计算模型,并结合算例采用数值方法分析了不同井口回压对气体膨胀抑制效果及井底压力的影响。在综合考虑抑制气体膨胀、控制井底压力降低幅度、井控装备工作安全和不同回压下井控人员心理压力等因素的前提下,给出了保持高压气井钻井安全宜施加2～5 MPa井口回压的建议。     

页岩气储层井周孔隙压力传递数值分析方法

由于页岩基质致密、层理和裂隙发育、富含黏土矿物,使得页岩具有超低渗透、各向异性和水敏等特性,钻井液与页岩接触产生的水化作用引起自由水在页岩中传输,从而导致井周孔隙压力不断变化,但现有方法并未考虑页岩物性特征的影响。为此,基于非平衡热动力学理论,建立了各向异性页岩的井周压力传递数学模型及有限差分求解方法,分析了井周压力分布特征、传递规律及影响因素。结果表明,各向异性页岩井周压力分布与井周角有关,并以主方向呈对称分布;钻井液化学作用对井周压力传递的影响显著,低浓度钻井液情况下井壁附近孔隙压力显著增加,而高浓度钻井液情况下却显著降低,井周压力传递集中在1倍井径范围内;井周孔隙压力的增加不利于井壁稳定,而孔隙压力的降低有利于井壁稳定;溶质扩散系数越小、膜效率系数越大、水力扩散系数越小,则井壁附近孔隙压力变化幅度越大;反之,孔隙压力变化幅度越小。该方法比常规方法更符合实际,且更加实用。     

根缘气（深盆气）成藏异常压力属性实验分析

主实验采用内径7cm、高75cm的耐压玻璃筒，分15段填入粒径为0．05～4mm的白色等径石英砂，构成向上逐渐变粗的递变“砂柱”，注入染成红色的水，石英砂柱分别与测压管相连。从玻璃筒底部向上注气，模拟注入的气体“活塞式”向上排驱孔隙水的过程，观察此过程中各砂粒段流体压力的变化过程。实验结果，注气速率较高时，粒径为0．3ram以下的砂粒段均可出现气水倒置并形成高异常流体压力，注气速率较低时只有粒径为0．15～0．2ram的砂粒段出现这些现象；不管注气速率高低，粒径大于0．3ram的砂粒段不出现气水倒置现象，保持常压。根据实验结果，认为典型根缘气(深盆气)成藏是高异常压力形成及其等压面推进的过程，因此原生地层压力应为高异常压力。盆地内部区域性高异常地层压力出现的顶界面可作为原生性根缘气藏的主要标志，可据该界面深度大致估计根缘气成藏时的注气压力。图3参11     

井筒气侵后井底压力变化的计算分析

钻井过程中一旦发生气侵,如果控制不当,容易出现井涌、井漏、井喷等井下复杂事故.为了更有效地控制钻井过程中的井底压力,确保钻井安全,根据钻井过程中井筒多相流动的特点,建立了井筒气侵后井底压力的计算模型,并利用有限差分法对模型进行了求解.通过仿真算例,讨论了排量、井口回压、钻井液密度、钻井液黏度、井底初始压差和气相渗透率对...     

TH油田凝析气藏水平井试井合理压差的确定

水平井产能试井主要是求取产能方程和绝对无阻流量,优选生产油嘴。水平井试井合理压差的确定实际上是与水平井合理产能相对应,而合理的产能是通过选择合理的油嘴来实现的。产能试井设计中的关键就是设计合适的油嘴,以获得稳定可靠的产量和压力资料。     

On the determination of the skin factor and the turbulence term coefficient through a single constant gas pressure test

The best correlation for evaluating the turbulence term coefficient, D(μ), for transient flow in gas wells under constant flow rate conditions is currently that of Lee et al. [Lee, R.L., Logan, R.W., Tek, M.R., 1987. Effect of turbulence on transient flow of real gas through porous media. SPE Form. Eval. (March), 108–120]. Several authors have used this correlation to calculate the production decline for wells that produce under constant bottomhole pressure conditions, but it is not clear if this is correct. When exploiting any gas reservoir, the flow rate and the average reservoir pressure decrease with time. This process makes D(μ) increase, whereas D(μ)q_sc decreases with time; in contrast, when a well is produced under constant flow rate conditions, D(μ)q_sc increases with time. Due to this fact, it can be of considerable practical interest to analyze the behavior of the high velocity pseudoskin factor, D(μ)q_sc, for gas wells that produce under constant bottomhole pressure conditions. This paper presents the results of a study aimed at obtaining a correlation of both the mechanical skin factor, s, and the turbulence term coefficient, D(μ), for constant bottomhole pressure conditions through the analysis of a single test. Results obtained through a radial real gas flow simulator, carefully validated for pseudosteady state conditions were used as a database for the development of the new correlations. The skin effect considered varies from 0 to 10. Two different gases are considered. Other variables studied are the constant pressure, the reservoir size r_e/r_w and formation permeability. The correlation is presented by means of straight-line fits of s_t/[s(1−r_w/r_d)] in the vertical axis and D(μ_i)q_sc in the horizontal axis. The correlation coefficient was 0.9976. The error obtained when one evaluates the skin factor, s, using the correlation presented in this work is less than 10%. The error is substantially less when production rates are low. These rates strictly correspond to the case of low permeability reservoirs, where the constant pressure boundary condition considered is this study closely apply.