页岩储层特殊性质对压裂液返排率和产能的影响

发布时间：2018-04-13 19:56

本文选题：页岩 + 数值模拟　；参考：《天然气地球科学》2017年06期

【摘要】：相对于常规储层,复杂的储层性质对页岩气井压后返排率高低和产能大小的影响更为显著。基于页岩气井早期生产返排特征,建立气水两相流数值模型,研究不同储层性质[超低含水饱和度、渗透率盲区(Permeability Jail)、润湿性和基质毛管力]对返排率和产能的影响。结果表明:在关井期间,储层"超低含水饱和度"现象导致压裂液大量渗吸,引起储层含水饱和度上升,最终使得初始开井产气量高,返排率低,且原始含水饱和度越低,影响越大;随着储层渗透率盲区程度增大,累产气量逐渐减小,强相渗盲区的储层生产3年仅有1.32×104 m~3的产气量。无相渗盲区(常规相渗曲线)的储层渗吸能力强,返排率极低(4.74%)。综合认为,弱相渗盲区储层的相渗曲线更适合页岩;储层基质水湿程度的降低会减弱渗吸置换能力,使得累产气量减小,返排率增加;储层基质毛管力的增大将导致渗吸作用加强,造成初始产气量升高,而在长期生产中,气相渗透率受到强渗吸引起的高含水饱和度的阻碍而降低,导致累产气量减少,并伴随着较低的返排率。
[Abstract]:Compared with conventional reservoirs, complex reservoir properties have a more significant effect on the rate of backflow and productivity of shale gas wells after compression.Based on the characteristics of early production and drainage of shale gas wells, a numerical model of gas-water two-phase flow is established to study the effects of different reservoir properties (ultra-low water saturation, permeability blind area, permeability Jailan, wettability and matrix capillary force) on the recovery rate and productivity.The results show that during well shutoff, the phenomenon of "ultra-low water saturation" in the reservoir leads to a large amount of permeability and suction of the fracturing fluid, which leads to the increase of the water saturation of the reservoir, and finally makes the initial open well gas production high, the rate of return and drainage low, and the original water saturation being lower.With the increase of the degree of the blind zone of reservoir permeability, the cumulative gas production decreases gradually, and the reservoir in the blind area of strong phase permeability produces only 1.32 脳 104 mm3 of gas for 3 years.The reservoir with no blind zone of phase permeability (conventional phase permeability curve) has strong permeability and low rate of return and drainage (4.74%).It is concluded that the permeability curve of the reservoir in the blind zone of weak phase permeability is more suitable for shale, and the decrease of the water and moisture degree of the reservoir matrix will weaken the ability of permeability absorption and replacement, which will reduce the cumulative gas production and increase the rate of return and discharge.The increase of capillary force of reservoir matrix will lead to the enhancement of permeability and increase of initial gas production, while in long-term production, the gas permeability will be reduced by the hindrance of high water saturation caused by strong permeability, resulting in the decrease of cumulative gas production.It was accompanied by a lower rate of reflux.
【作者单位】：中国石油大学(北京)石油工程教育部重点实验室;中国石油勘探开发研究院廊坊分院;中国石油集团长城钻探工程有限公司录井公司国际业务项目部;
【基金】：国家自然科学基金重大项目(编号:51490654) 国家科技重大专项(编号:2016ZX05023;2016ZX05039)联合资助
【分类号】：TE31

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