致密气藏分段压裂水平井生产数据分析方法

发布时间：2018-07-27 16:34

【摘要】：致密砂岩气藏开发过程中,由于砂岩储层过于致密,导致储层的渗透性很差,因此多采用分段压裂水平井进行开发,以期获得较高的气井产能。由于致密气藏的特殊性,很容易出现单井控制储量小、产能低、产量递减快、最终采收率低等一系列问题,本文通过对理论进行研究并结合实例进行论证,给出了一种通过分析生产数据来评价水平井的产能的新方法。首先,本文通过对垂直裂缝井在生产初期其地层中的渗流和裂缝中的渗流特征进行分析,分别建立对应的物理数学模型,通过耦合方程得到垂直裂缝井初期产能的解析解,由于早期阶段尚未形成缝间干扰,通过叠加直接得到多条裂缝情况下的初期产能。其次,考虑缝间干扰、裂缝不均匀分布以及各裂缝导流能力差异,运用空间多井(多裂缝)叠加理论建立了多裂缝拟稳态渗流线性方程组,在定井底流压的条件下,求解得到封闭储层拟稳态渗流阶段分段压裂水平井的产能。在多裂缝生产的条件下,裂缝的拟稳态产能主要影响因素为裂缝无量纲导流能力、每条裂缝所占据的泄流面积。再次,通过引入当量井径和井筒聚流表皮模型,根据压降叠加原理建立了带有多条有限导流垂直裂缝的水平井不稳态产能分析新方法。计算分析表明,裂缝与裂缝之间存在相互干扰现象,在等长均匀分布情况下外侧裂缝所占的产量百分比最大,而中间的裂缝增产效果相对较小;随着裂缝条数的增加,水平井的总产量逐渐增加但增加幅度渐小,而每条裂缝的产量逐渐减小,由此结合经济评价可以得到最优裂缝条数。最后,通过与商业数值模拟软件Eclipse和生产数据分析软件RTA做计算分析对比,验证本文的研究结果,并将本文的研究结果用于生产动态分析方法中,在限定流压的情况下预测稳定生产年限。
[Abstract]:During the development of tight sandstone gas reservoir, because the sandstone reservoir is too tight, the permeability of the reservoir is very poor, so it is often developed by fracturing horizontal wells in order to obtain high gas well productivity. Because of the particularity of tight gas reservoir, a series of problems such as small control reserves, low productivity, fast production decline and low final recovery are easy to occur. A new method for evaluating the productivity of horizontal wells by analyzing production data is presented. Firstly, by analyzing the percolation of vertical fractured wells in the early production stage and the percolation characteristics of fractures, the corresponding physical mathematical models are established, and the analytical solutions of initial productivity of vertical fractured wells are obtained by coupling equations. The initial productivity of multiple fractures can be obtained directly by superposition due to the fact that interfracture interference has not been formed in the early stage. Secondly, considering the interfracture interference, the uneven distribution of fractures and the difference of the conductivity of each fracture, the linear equations of quasi steady seepage flow of multi fractures are established by using the theory of space multi well (multi fracture) superposition, under the condition of determining the bottom hole flow pressure, The productivity of segmented fracturing horizontal wells in pseudo-steady seepage stage of closed reservoir is obtained. Under the condition of multi-fracture production, the main influencing factors of quasi-steady production capacity of fractures are the dimensionless conductivity of cracks and the discharge area occupied by each crack. Thirdly, a new method of unsteady productivity analysis for horizontal wells with multiple vertical fractures with finite conductivity is established by introducing the equivalent diameter and wellbore flow accumulation skin model according to the principle of pressure drop superposition. The calculation and analysis show that there is mutual interference between fractures and fractures. Under the condition of uniform distribution of equal length, the percentage of output of lateral fractures is the largest, while the effect of increasing production of middle fractures is relatively small, and with the increase of the number of cracks, The total production of horizontal well increases gradually but the increase range is smaller and the output of each fracture decreases gradually. Thus the optimal number of fractures can be obtained by combining with economic evaluation. Finally, by comparing with commercial numerical simulation software Eclipse and production data analysis software RTA, the research results of this paper are verified, and the research results are used in the production dynamic analysis method. The stable production life is predicted under the condition of limited flow pressure.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE328;TE37

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