【作者】 赵静；

【导师】 刘义坤；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2008， 博士

【摘要】 水平井开采技术已经成为老油田挖潜、新油田开发、提高采收率的重要手段,在油田开发设计中得到了越来越广泛的应用,尤其是对低渗透油藏,用普通直井开发难取得很好的经济效益,而利用水平井开发可获得一定的生产能力。目前,油藏工程研究方面,对水平井产能分析计算的成果较多,国内外有关水平井及分支井与直井联合开发低渗透油藏渗流理论的研究还很少见,处于起步阶段,这是油藏工作者面临的一个崭新的研究课题。本文针对低渗透油藏渗流规律不符合达西定律,普遍存在启动压力梯度的特点,采用渗流力学、油藏工程等基本原理,对低渗透油藏水平井及分支井与直井联合开发渗流理论进行了系统的研究,建立了低渗透油藏水平井及分支井与直井联合开发井网条件下产能计算方程,取得了以下主要认识和结果:研究了低渗透油藏不同边界条件下水平井单井开发渗流理论及分支井开发渗流理论,利用势的叠加原理、保角变换和等值渗流阻力法,考虑启动压力梯度,建立起低渗透油藏水平井及分支井产能计算方程,公式简单,并具有较高精度。对低渗透油藏水平井产能的计算结果表明,它更接近实际低渗透油藏水平井及分支井产能。推导出低渗透油藏水平井及分支井与直井联合开发不同井网布井方式时产能计算方法,分析了各种因素的影响,利用该公式计算表明,随着启动压力梯度的增大,水平井、分支井井网产能减小,启动压力梯度对水平井及分支井不同井网产能影响程度随着穿透比的增大而减小。建立了低渗透油藏水平井不稳定渗流的数学模型,引入了含有启动压力梯度,压力和半径等参数的有效驱动因子,从有效驱动因子、启动压力梯度等方面分析了水平井产能的影响因素,结果表明,随着启动压力梯度的增大,水平井产量逐渐减小,随着有效驱动因子的增大,水平井产量逐渐增大。研究了低渗透油藏水平井油气两相渗流理论,建立了低渗透油藏水平井油气两相渗流数学模型,实例的计算分析表明,相同井底流压时,启动压力梯度越小,产量越大,对于低渗透油藏应尽量减小启动压力梯度的影响。研究了低渗透油藏水平井流入流出动态,选取井底作为节点,给出不同启动压力梯度时低渗透油藏水平井合理产量,该理论为现场应用水平井开发低渗透油藏合理产量、合理工作制度的选择具有一定的参考价值。本论文的研究成果着重于低渗透油藏用水平井开发的理论探讨,尤其给出了低渗透油藏分支水平井与直井联合开发的产能计算方法,为开发低渗透油藏提供了新的理论依据;同时也扩展了水平井产能预测的理论和方法。更多还原

【Abstract】 Horizontal well’s technique of mining has become an important means of enhancing oil recovery, digging old oilfield and developing new oil fields. It was more widely used in developing and designing oil field. Especially for the low permeability reservoir, it’s hard to obtain good economic benefits with using normal vertical wells technique, but we can obtain some production capacity if we developed low permeability reservoir with horizontal wells. At present, the fruit of analysis and calculation to horizontal well’s production is more on research reservoir engineering. The research of filtration theory was very rare in domestic and foreign, which was that apply branch wells, horizontal wells combining vertical wells to develop low permeability reservoir. It is at initial stage and it is a new research theme for reservoir workers. In view of the feature that filtration law was not Darcy law and starting pressure gradient was ubiquitous presence in low permeability reservoir, adopted fundamental principle such as dynamic of fluids through porous media, reservoir engineering and so on, filtration theory was systematically studied, it was that low permeability reservoir was developed by the combination of horizontal well, branch well and straight well. Established deliverability equation under the situation that hole pattern was jointly developed by the combination of horizontal well, branch well and straight well, this article mainly made such cognizance and result as follows:Single well development filtration theory of horizontal well in low permeability reservoir was studied under different boundary conditions and so did branch well development filtration theory. Used potential’s principle of superimposition, conformal transformation and equivalent filtrational resistance, considered starting pressure gradient, established deliverability equation of horizontal well and branch well of low permeability reservoir. The equation was simple and it had more accuracy degree. The computational solution to horizontal well’s deliverability of low permeability reservoir showed the equation was much close to actual horizontal well and branch well’s deliverability of low permeability reservoir.Derived deliverability computational method under the situation that different hole pattern was jointly developed by the combination of horizontal well, branch well and straight well in low permeability reservoirs. The influence of various factors is analyzed. The computational result of the formula showed that with the increase of starting pressure gradient, well network’s production of horizontal well and branch well decreased; with the increase of penetrated ratio, starting pressure gradient’s degree of influence on different hole pattern of horizontal well and branch well decreased.Established non-stabilized flow mathematical model of horizontal well of low permeability reservoir, drew effective drive factor which included such as parameters: starting pressure gradient, pressure and radius and so on. From effective drive factor, starting pressure gradient and so on angles, we analyzed affecting factor on horizontal well’s production. The result showed that with the increase of starting pressure gradient, horizontal well’s production was gradually reducing; with the increase of effective drive factor, horizontal well’s production gradually increase.The flow theory of oil-gas two-phase of horizontal well in low permeability reservoir was studied, established mathematical model oil-gas two-phase flow. By the calculation and analysis of analysis example, when BHFP was same, the smaller starting pressure gradient was, the higher the production was. We should decrease starting pressure gradient’s influence for low permeability reservoir as far as possible.Horizontal well’s inflow-out performance of low permeability reservoir was studied, selected bottom of a well as a node, horizontal well’s reasonable production was given under different starting pressure gradient. This theory had some reference value for choosing reasonable working system and reasonable output of low permeability reservoir’s development with application horizontal well on oil field.This paper’s fruit focused on theory research about developed low permeability reservoir with horizontal well, especially deliverability calculation method was given. The method was developed by the combination of branch horizontal well and vertical well in low permeability reservoir. It has provided a new theory basis for low permeability reservoir’s s development, at the same time, it has expanded theories and methods of horizontal well production forecast.更多还原