渤南5区低渗透油田应力场特征及影响因素研究

发布时间：2019-04-26 21:09

【摘要】：渤南低渗透油田位于渤南油田东南部,经过多年开发,油藏平面、层间矛盾突显,严重影响后期开发。为了进一步挖潜,需要对油层压裂改造和井网调整。开展油田应力场分布特征及变化规律研究,对于指导油井压裂改造与井网部署调整具有重要意义。本文通过对渤南5区低渗透油田应力场特征及影响因素研究,取得了以下成果及认识。利用Maurice A.Biot所创立的线性孔隙弹性理论作为数值模拟的理论框架,建立了渤南5区应力场地质模型和数学模型,编制了应力场模拟的辅助分析FISH文档。模拟了渤南5区Y5-21井区和Y65-1井区应力场分布特征,在Y5-21井区,随着注采强度的减弱,动态生产对地应力的扰动效应也相应减弱。在发生转注以后,转注井周围地应力影响效应发生反转,其影响范围主要局限于转注井周围井距大小范围内。而hσ大小分布与砂泥岩界限有较强的相关性,泥岩层内的hσ值变化很小。在Y65-1井区,注采强度越大,hσ值变化范围越大,hσ偏转量也最大。在注水井关井阶段,hσ绝对值相对于初始绝对值减小。整体上Y65-1井组区在开发过程中水平方向上最小主应力hσ偏转量较小。研究了模型静态参数对地应力影响,杨氏模量对水平方向上主应力的方向偏转会产生较微小的影响,岩石泊松比对水平方向上应力方向偏转量几乎不存在影响。而Biot系数对水平方向上最大、最小主应力值和方向偏转量的影响较其它模型参数大。研究了生产动态因素对地应力的影响,对于单井采注,随着采油井井底流压的降低(开采产量的加大),不同模型相同位置上的hσ绝对值呈减小趋势,不同模型相同位置上hσ偏转量呈增大趋势;当注水井注水压力的提高或注水量的增加时,水平方向的主应力绝对值随之增加。而多井注采将导致模型某些区域hσ偏转量增大。探讨了井网分布形式对地应力的影响,对五点法井网,仅在注采强度变化的情况下,整个地应力的扰动强度与注采强度呈现正相关。相同生产条件下,五点法井网注采时,hσ最大偏转量小于与一注两采同等压差条件下hσ的变化量;这说明hσ的偏转并不是采油井、注水井影响效果的简单叠加。
[Abstract]:Bonan low permeability oil field is located in the southeast of Bonan oilfield. After many years of development, the contradiction between layers and reservoirs is highlighted, which seriously affects the later development. In order to tap the potential further, reservoir fracturing modification and well pattern adjustment are needed. It is of great significance to carry out the research on the distribution and variation of stress field in oil field, which is of great significance to guide the fracturing transformation and the adjustment of well pattern deployment. Based on the study of stress field characteristics and influencing factors of low permeability oilfield in Bonan area 5, the following achievements and understandings have been obtained in this paper. Using the theory of linear porosity elasticity established by Maurice A.Biot as the theoretical framework of numerical simulation, the geological model and mathematical model of stress field in Bonan 5 area are established, and the FISH documents for auxiliary analysis of stress field simulation are compiled. The distribution characteristics of stress field in well Y5-5 and well Y65-1 in Bonan 5 area are simulated. With the decrease of injection-production intensity, the disturbance effect of dynamic production on in-situ stress is also weakened. After injection transfer, the effect of in-situ stress on the reinjection well is reversed, and the influence range is mainly limited to the well spacing around the transfer well. However, there is a strong correlation between the distribution of h 蟽 and the boundary of sand and mudstone, and the change of h 蟽 value in mudstone is very small. In Y65-1 well area, the greater the injection-production strength, the larger the variation range of h 蟽 value and the maximum h 蟽 deflection. In the closing stage of water injection well, the absolute value of h 蟽 decreases relative to the initial absolute value. On the whole, the minimum principal stress h 蟽 deflection in the horizontal direction of Y65 1 well group area is relatively small. The influence of static parameters of the model on the in-situ stress is studied. The Young's modulus has a small effect on the direction deflection of the principal stress in the horizontal direction, and the Poisson's ratio of rock has little effect on the deflection of the stress direction in the horizontal direction. However, the influence of Biot coefficient on the maximum, minimum principal stress and direction deflection in horizontal direction is greater than that in other models. The influence of production performance factors on in-situ stress is studied. For single-well injection, the absolute value of h 蟽 in the same position of different models decreases with the decrease of bottom hole flow pressure (increase of production output). The deflection of h 蟽 at the same position in different models tends to increase. The absolute value of principal stress in horizontal direction increases with the increase of water injection pressure or water injection in injection wells. However, multi-well injection and production will lead to the increase of h 蟽 deflection in some areas of the model. The influence of well pattern distribution on the in-situ stress is discussed. For the five-point well pattern, the disturbance intensity of the in-situ stress is positively correlated with the injection-production intensity only under the condition of the change of injection-production intensity. Under the same production conditions, the maximum deflection of h 蟽 is less than that of h 蟽 under the condition of the same pressure difference between one injection and two production under the same production conditions, which shows that the deflection of h 蟽 is not a simple superposition of the effect of injection wells and injection wells.
【学位授予单位】：中国科学院研究生院(广州地球化学研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE31

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