ST油藏产量递减规律及提高采收率对策研究

发布时间：2018-05-29 08:48

本文选题：产量递减 + 油藏数值模拟　；参考：《西南石油大学》2017年硕士论文

【摘要】：ST油藏是以三角洲平原、河流相及浊积相沉积为主的高孔高渗多层砂岩油藏,自1965年投入正式生产,至今已有52年的开发历史,目前已进入特高含水开发后期,总体看来主要存在以下特点:(1)产量递减速度快,油藏年产油量表现出大幅降低的趋势,自然递减率大;(2)非均质性强,无论在层间还是平面上,均已严重水淹,地下剩余油分布零散复杂,挖潜难度越来越大;(3)开发井网与开采方式无法满足现阶段开发要求,水驱控制程度低,井况日益变差,现有井网的注采对应率差,地层能量下降,严重制约着油田的稳产形式。因此,为确保ST油藏稳产甚至增产、实现油田持续稳定发展,必须对ST油藏地质特征做重新认识,弄清ST油藏单井及全区产量递减规律以及ST油藏剩余油分布规律,进而找到ST油藏特高含水开发后期有效的提高采收率对策。本文从ST油藏构造特征、地层特征、储层特征、流体特征等进行研究,重新认识该油藏的地质特征。由产量递减率的定义,依据油藏工程原理和渗流理论,推导分析得出影响产量递减的8项因素,并提出了减缓产量递减的主要措施。运用4种常用的产量递减规律确定了适合各研究井的产量递减方程,并预测得到各研究井的可采储量。采用5种常用的油田产量预测模型对ST油藏递减阶段的生产资料进行分析,可得在ST油藏递减阶段运用双曲递减模型和衰减曲线模型预测年产油量和累积产油量的效果最好。综合地质研究成果,采用三维地质建模,建立了 ST油藏构造模型和属性模型。储量复算结果显示,模型地质储量与已知地质储量相比,增加了 43.4万吨,误差为3.87%,表明建立的地质模型质量是可靠的。凭借油藏数值模拟技术,建立了 ST油藏数值模拟模型。对数值模拟历史拟合质量进行评价,结果显示:全区地层压力模拟值随开发时间的变化趋势与实际地层压力随开发时间的变化趋势保持一致、储量拟合的相对误差为3.09%、综合含水率平均绝对误差为1.7%、累积产油量相对误差为2.7%、累积产液量相对误差0.4%,表明建立的数值模拟模型具有可靠的质量。在此基础上,从油藏纵向和平面两方面开展剩余油分布数值模拟研究,并根据剩余油分布研究成果,有针对性的提出了各类小层合理的提高采收率对策。最后进行ST油藏提高采收率对策部署设计,并预测调整后的油藏未来开发指标。数值模拟开发指标预测结果显示,调整后采液速度提高了 5.95%,采油速度提高了 0.45%,综合含水率下降了 1.1%,累积产油量增加了 24.43万吨,采出程度提高了 4.14%,产量递减率整体得以减缓,获得了较好的开采效果,表明挖潜对策是可行的。
[Abstract]:St reservoir is a multilayer sandstone reservoir with high porosity and high permeability, which is mainly composed of delta plain, fluvial facies and turbidite facies. It has been developed for 52 years since it was put into production in 1965. On the whole, there are the following main characteristics: the production decline rate is fast, the annual oil production of the reservoir shows a tendency to decrease substantially, and the natural decline rate is strong and the heterogeneity is strong. Both in the interlayer and in the plane, the oil production has been seriously flooded. The distribution of remaining underground oil is scattered and complex, and it is becoming more and more difficult to tap potential. The development pattern and production mode can not meet the requirements of development at present, the degree of water drive control is low, the well condition is getting worse and worse, the corresponding rate of injection and production of existing well pattern is poor, and the formation energy is decreased. The stable production form of oil field is seriously restricted. Therefore, in order to ensure stable production or even increase production of St reservoir and realize the sustainable and stable development of oil field, it is necessary to re-understand the geological characteristics of St reservoir, clarify the law of production decline in single well and whole area of St reservoir and the distribution law of remaining oil in St reservoir. And then find out St reservoir super high water cut in the later stage of development effective measures to improve oil recovery. In this paper, we study the structural, stratigraphic, reservoir and fluid characteristics of St reservoir, and re-understand the geological characteristics of this reservoir. According to the definition of production decline rate, according to reservoir engineering principle and percolation theory, eight factors affecting production decline are deduced and analyzed, and the main measures to slow down production decline are put forward. The production decline equations suitable for each research well are determined by using four common production decline laws and the recoverable reserves of each research well are predicted. By using five commonly used oil field production prediction models to analyze the production data in St reservoir decline stage, it is concluded that the hyperbolic decline model and attenuation curve model are the best in predicting annual oil production and cumulative oil production in St reservoir decline stage. The structural model and attribute model of St reservoir are established by three-dimensional geological modeling. The results of reserves calculation show that compared with known geological reserves, the model geological reserves increase by 434000 tons and the error is 3.87, which indicates that the quality of the established geological model is reliable. Based on reservoir numerical simulation technology, St reservoir numerical simulation model is established. The quality of historical fitting of numerical simulation is evaluated. The results show that the variation trend of formation pressure simulation value with development time is consistent with that of actual formation pressure with development time. The relative error of reserve fitting is 3.09, the average absolute error of comprehensive water cut is 1.7, the relative error of cumulative oil production is 2.7, and the relative error of cumulative liquid production is 0.4, which indicates that the established numerical simulation model has reliable quality. On this basis, the numerical simulation of residual oil distribution is carried out from the vertical and plane aspects of the reservoir, and according to the research results of residual oil distribution, the reasonable measures to improve oil recovery are put forward. Finally, the St reservoir enhanced recovery countermeasures are designed, and the adjusted reservoir future development index is predicted. The prediction results of the numerical simulation development index show that after adjustment, the liquid recovery rate has increased 5.95%, the oil recovery speed has increased 0.45%, the comprehensive water cut has decreased 1.1%, the cumulative oil production has increased 244300 tons, The recovery degree was increased by 4.14%, and the production decline rate was slowed down as a whole, and a better mining effect was obtained, which indicates that the strategy of tapping potential is feasible.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE327;TE357

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