致密油藏压裂水平井产能研究

发布时间：2018-02-24 03:37

本文关键词： 致密油藏渗透率应力敏感压裂水平井稳态产能非稳态产能　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：致密油藏由于渗透率低,采用直井开发致密油藏一般无自然产能,因此常采用压裂水平井对致密油藏进行开发。为了提高水平井压裂施工参数设计的准确性,提高开发效益,需要对压裂水平井产能模型进行研究。以鄂尔多斯盆地某致密油藏为研究对象,通过室内岩心实验、流态特征识别和理论模型建立等方法,对致密油藏的压裂水平井的产能预测和影响因素分析优化等方面进行了研究,完成了以下工作并取得了一些认识:(1)开展了地层条件下的应力敏感实验,得到的H井区、J井区、L井区和W井区基质岩样的指数式平均应力敏感系数分别为0.0073MPa-1、0.0205MPa-1、0.0244MPa-1和0.01e3MPa-1,证明致密油藏存在渗透率应力敏感性。(2)以保角变换法和叠加原理为基础,推导了考虑应力敏感的致密油藏压裂水平井稳态产能模型,进行了实例计算,并与其它经典的压裂水平井稳态产能公式的计算结果进行了比较。结果表明,由于考虑了渗透率应力敏感,本文推导的稳态产能模型与其它模型相比误差更小,精度更高。(3)利用推导的稳态产能模型,分析了裂缝条数、裂缝长度、裂缝导流能力和渗透率应力敏感系数对压裂水平井产能的影响。其中,日产油量随着裂缝条数的增加而增加,但增加幅度随着裂缝条数的增加而减少;日产油量随着裂缝长度的增加而增加,增加幅度基本呈线性;压裂水平井的产量随裂缝导流能力的增加而增加,但增加幅度减小,在同一裂缝导流能力情况下,随着裂缝长度的增加,压裂水平井的产能也增加;随着应力敏感系数的增大,同一压差下的压裂水平井产能下降幅度也增大,增大压差所造成的产能降幅也越大,所以应保持合理的生产压差。(4)压裂水平井渗流过程中会出现相应的流态,用流态特征识别的方法分析了压裂水平井生产过程中的流态特征,根据流态特征建立了相应的产能方程,耦合后得到了考虑应力敏感的致密油藏压裂水平井非稳态产能预测模型。(5)利用推导的非稳态产能模型,对致密油藏四个井区的每类储层各设计了一口压裂水平井进行产能影响因素优化,得到了各参数的优化值。分析了应力敏感对压裂水平井产能的影响,当定井底压力生产,应力敏感系数的变化仅造成压裂水平井相对产量的高低,对压裂水平井产量的递减趋势并无影响。本文的研究成果为致密油藏压裂水平井的产能预测、工作制度的确定和压裂施工参数设计提供了参考。
[Abstract]:Because of the low permeability of tight reservoir, the development of tight reservoir by using straight well has no natural productivity, so fracturing horizontal well is often used to develop the tight reservoir, in order to improve the accuracy of fracturing operation parameter design of horizontal well and improve the benefit of development. It is necessary to study the productivity model of fracturing horizontal well. Taking a tight reservoir in Ordos Basin as the research object, through laboratory core experiments, the identification of flow characteristics and the establishment of theoretical model, etc. In this paper, the productivity prediction of fractured horizontal wells in tight reservoirs and the analysis and optimization of influencing factors are studied. The following works have been accomplished and some understandings have been obtained. (1) Stress-sensitive experiments under formation conditions have been carried out. The exponential average stress sensitivity coefficients of the matrix rock samples obtained from the He-J well area and the W well area are 0.0073 MPa-1 and 0.0205MPa-1 0.0244MPa-1 and 0.01e3MPa-1, respectively. It is proved that the permeability stress sensitivity of tight reservoirs is based on the conformal transformation method and the principle of superposition. The steady-state productivity model of fractured horizontal wells in tight reservoir considering stress sensitivity is derived, and a practical example is calculated. The results are compared with those of other classical formulas for calculating the steady-state productivity of fracturing horizontal wells. The results show that, Considering permeability stress sensitivity, the steady-state productivity model derived in this paper has smaller error and higher precision than other models. (3) by using the derived steady-state productivity model, the fracture number and fracture length are analyzed. The effect of fracture conductivity and permeability stress sensitivity coefficient on the productivity of fractured horizontal wells, in which the daily oil production increases with the increase of the number of fractures, but the increasing range decreases with the increase of the number of fractures. The daily oil production increases with the increase of fracture length, and increases linearly, while the production of fractured horizontal wells increases with the increase of fracture conductivity, but the increase decreases, under the condition of the same fracture conductivity, the daily oil production increases with the increase of fracture length, and the oil production increases linearly with the increase of fracture conductivity. With the increase of fracture length, the productivity of the fractured horizontal well also increases, and with the increase of the stress sensitivity coefficient, the productivity of the fractured horizontal well under the same pressure difference increases, and the greater the pressure difference, the greater the productivity decrease. Therefore, it is necessary to maintain a reasonable production pressure difference. 4) the corresponding flow state will appear in the percolation process of the fractured horizontal well, and the characteristics of the flow state in the production process of the fracturing horizontal well are analyzed by the method of identifying the flow state characteristics. According to the characteristics of flow state, the corresponding productivity equation is established, and the unsteady productivity prediction model of fractured horizontal wells considering stress sensitivity is obtained by coupling. A fracturing horizontal well is designed for each type of reservoir in four well areas of dense reservoir to optimize the productivity factors, and the optimized values of each parameter are obtained. The effect of stress sensitivity on the productivity of fractured horizontal well is analyzed. The change of stress sensitivity coefficient only causes the relative production of fractured horizontal wells, and has no effect on the decline trend of fracturing horizontal wells. The research result of this paper is the prediction of productivity of fractured horizontal wells in dense reservoirs. The determination of working system and the design of fracturing operation parameters provide reference.
【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】：TE328

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