共查询到19条相似文献,搜索用时 203 毫秒
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研究表明低渗透油藏渗流规律不符合达西定律.根据学者在低渗透非达西多相渗流的数值模拟分析中提出的渗流速度和压力梯度关系,进一步提出了变渗透率效应概念,建立了低渗透油藏通用非达西渗流试井模型,采用追赶法对变渗透率效应差分方程组迭代求解.对渗透率取几何平均数,解决了迭代求解过程中解的振荡不收敛问题.计算结果表明:变渗透率效应持续时间越短,压力曲线及压力导数曲线上翘越大.基于变渗透率效应建立的通用非达西渗流试井模型及其求解的方法比目前动边界计算方法稳定性更好,比较符合实际情况.达西渗流试井模型只是低渗透油藏通用非达西渗流试井模型的特例. 相似文献
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低渗透多孔介质中新型渗流模型 总被引:11,自引:0,他引:11
在低渗透多孔介质中,由于流体的渗流规律不遵循达西定律,以往的模型或者过于简单,或者过于复杂,研究建立了更加接近渗透多孔介质中流体真实流动,且形式简单的三参数渗流模型。并对低渗透油藏中径向稳定渗流和不稳定渗流进行了分析。通过对边水油藏生产压差和产量关系的分析,说明了以达西定律为基础的渗流模型不适合于低渗透油藏,在相同的条件下,其计算的产量偏大。通过对非稳态渗流的分析,给出了基于三参数模型的试井公式和典型试井曲线,低渗透油藏试井曲线的特征是中后期径向流特征段消失,压力和压力导数曲线上升。 相似文献
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低渗透油气藏中常出现低速非达西渗流。对于层状低渗油气藏,层间非均质性一般较强,考虑非均质性的影响,可以把层状油藏的渗透区域看作双渗透油藏。充分考虑启动压力梯度与动边界的影响,建立微可压缩双渗透油藏低速非达西渗流有效井径试井的数学模型,求出其数值解,绘制有界油藏定压条件下层间储容比和层间窜流系数影响的典型试井曲线,对动边界的传播规律进行分析。本文方法可用于其它油藏类型(如双重介质等)试井分析图版的创建。 相似文献
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在已有的Fetkovich和Blasingame等生产数据分析方法的基础上,建立了圆形边界均质油藏垂直井径向流下的非达西渗流模型,绘制了Fetkovich与Blasingame非达西流情况下的典型曲线。该连续生产数据分析方法能通过不关井的连续监测生产数据获得常规关井试井分析同样的油藏解释成果数据,解决了低渗透油藏长时间连续监测资料分析应用问题。 相似文献
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文中给出了Forchheimer非达西渗流方程的二项式解。试井实例表明,利用二项式得到的非达西渗流湍流系数计算的产能与经验公式计算结果一致,说明了湍流系数可用于气藏工程产能预测和气藏方案设计。笔者导出的非达西渗流湍流系数理论方程与湍流系数经验公式具有一致性。理论方程分析可知,渗透率越低,非达西渗流湍流系数越高;高渗透储层不一定比低渗透储层更易产生高速非达西流气藏,不能根据非达西渗流的湍流系数来判断,而应根据储层流动的雷诺数高低来判断。 相似文献
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A rigorous semi-analytical model is developed to study the production rate behavior of wells in gas reservoirs with Forchheimer's non-Darcy flow under constant or varying bottomhole pressure conditions. Rigorous modeling of gas property variation in reservoirs is integrated in this model.Three dimensionless parameters, normalized gas viscosity and compressibility product, Forchheimer number, and normalized viscosity, are introduced to quantify their effects on non-Darcy flow in the reservoir. The variation of viscosity and compressibility product in the gas reservoir depletion process leads to a smaller production decline rate than that of exponential decline. The parameter b in Arps' decline equation under Darcy flow is defined as the base value, b, that helps identify the production decline caused by reservoir non-Darcy flow. Under the condition of constant pressure drop the more severe the non-Darcy flow, the larger the Forchheimer number. Generally, non-Darcy results in a smaller production rate, a larger decline rate in the boundary-dominated period, and a longer transition period between these two periods. The viscosity variation enhances non-Darcy flow, which lowers the initial production rate but has very little effect on the production decline rate. A larger production decline rate during the boundary-dominated period may help petroleum engineers identify the non-Darcy flow effect from the production data.Analyses show that the traditional quadratic equation is a good approximation only if non-Darcy flow is not severe and that for non-Darcy flow in the reservoir, the traditional Fetkovich's type curves may underestimate reservoir permeability, overestimate well skin factor, and misinterpret reservoir drainage area. A method of using the proposed model to identify the non-Darcy flow from production data is presented. Two examples from the literature are analyzed, and good type curve matches and more reliable results are obtained. 相似文献
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高速非Darcy流导致附加的压力损失,降低流体的流动效率,对油气生产十分不利。到底是低渗透储层容易产生高速非Darcy流,还是高渗透储层容易产生,一直没有明确的认识。前人研究结果显示,低渗透储层容易产生高速非Darcy流,但低渗透储层的流体流动极其困难,生产过程很难产生高的渗流速度。该文根据流体力学的相关知识,研究了高速非Darcy流产生的条件和高速非Darcy流的影响因素,并认为:高渗透储层容易产生高速非Darcy流,而低渗透储层不容易产生,低渗透储层的开发过程可忽略高速非Darcy流的影响。 相似文献
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Torsten Friedel Hans-Dieter Voigt 《Journal of Petroleum Science and Engineering》2006,54(3-4):112-128
Inertial non-Darcy flow effects can significantly lower the productivity of fractured gas wells. The effects were investigated numerically, taking into account inertial flow in the fracture and the reservoir. Simulations are performed by means of a fully-implicit in-house simulator. The non-Darcy flow implementation is based on an implicit treatment with relaxation of the non-Darcy control parameter. Contrary to the conventional method, the present approach facilitates the consideration of highly inertial flow and accounts also for permeability (stress) dependency of non-Darcy flow coefficients. The simulation tool is applied to a synthetic production scenario in typical tight-gas wells for constant and stress-dependent parameters. Results suggest that non-Darcy flow effects will influence the productivity despite the relatively low gas rates. Regarding a realistic scenario, the total gas production is reduced by 21% to 40%. New type-curves are presented for fracture and reservoir non-Darcy flow to identify the impact of reservoir non-Darcy flow and to facilitate the prediction of the performance of a fractured well. Technical contributions in this paper include (i) the illustration of stable and robust non-Darcy flow implementation in a fully-implicit reservoir simulation tool, (ii) unfolding the impact of inertial flow effects on a tight-gas well, and (iii) developing new type-curves accounting for non-Darcy flow in the reservoir and the fracture. 相似文献
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考虑非达西渗流的底水锥进临界产量计算模型 总被引:1,自引:0,他引:1
底水锥进是底水气藏开发的重要问题。有关临界产量计算模型的物理模型一般假设地层流体为达西渗流,忽略非达西渗流压降。对于高产气井,近井地带流体渗流速度很大,非达西渗流阻力不可忽略。笔者在临界产量计算模型中考虑高速非达西渗流对底水锥进的影响,引入拟表皮系数,建立了考虑非达西渗流的底水锥进临界产量计算模型,计算中避免了非达西渗流半径的复杂计算过程。为量化非达西渗流的影响,应用数值模拟方法,通过建立高渗、中渗、低渗底水气藏数值模型,模拟产能试井过程并建立产能方程,计算了考虑非达西渗流的底水锥进临界产量。结果表明:低渗气藏非达西渗流对临界产量计算结果的影响可以忽略;当渗透率为30 mD、射孔厚度为208.3m、避水高度为31 m时,未考虑非达西渗流的临界产量误差为14.46%,非达西渗流影响不可忽略。因此当渗透率大于30 mD时,应选用考虑非达西渗流的底水锥进临界产量计算模型,更符合实际储层流体渗流规律。 相似文献
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低渗透高含水砂岩气藏产能评价 总被引:1,自引:0,他引:1
针对目前低渗透气藏气水同产井产能评价时遇到的问题,依据渗流力学中气水两相不稳定渗流的基本方程,采用气藏工程方法和改进的修正等时试井方法及热力学原理,并考虑井下油嘴节流及气体高速非达西和滑脱效应的影响,提出了低渗透高含水气藏的产能评价方法。该方法在理论推导的基础上,对气水两相广义拟压力和修正等时试井方法进行了改进,最后结合井下油嘴节流原理和气体通过油嘴时的滑脱效应方程,利用热力学方法和数值分析方法,求出气水同产井的产气能力及最大携液流量。根据模拟井数据,分别用传统产能评价方法和上述方法进行了计算,计算结果表明:传统方法的计算值偏高,而上方法的计算结果比较符合实际。这为低渗透高含水气藏下入井下节流器的气井的产能评价提供了新的思路。 相似文献
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��This paper analyses the effect of various factors on the non-Darcy low-velocity unsteadystate seepage flow of natural gas, establishes a mathematical model of non-Darcy low-velocity unsteady-state seepage flow for the ideal and real gas, obtains the corresponding solution and long-time asymptotic solution through Laplace transform, and presents a necessary theoretical basis for the interpretation of pressure build-up curve of low capacity gas well and for the analysis of the performance of low permeability gas reservoir development. 相似文献
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R. Z. Yu Y. N. Bian Q. Lei Z. M. Yang K. J. Wang 《Petroleum Science and Technology》2013,31(16):1617-1624
A newly developed low-velocity non-Darcy flow numerical simulator is applied to the Fuyu formation. The three-dimensional geological model of subject reservoir was established and 9 well plans were designed to obtain the optimal well adjustment plan. Additionally, the formation pressure gradient distributions were provided and the flow regions were divided to study the adaptability of different well adjustment plans. The numerical simulation of Da45 reservoir is an excellent opportunity to: (1) put the non-Darcy flow numerical simulator into application, (2) provide guidance for the Da45 reservoir, and (3) provide reference to the non-Darcy flow numerical simulation technique. 相似文献