西南石油大学学报(自然科学版)

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基于扩散的页岩气藏压裂水平井渗流模型研究

郭小哲1 *,周长沙2   

  1. 1. 中国石油大学(北京)石油工程学院,北京昌平102249
    2. 中国石化东北石油局,吉林长春130062
  • 出版日期:2015-06-01 发布日期:2015-06-01
  • 通讯作者: 郭小哲,E-mail:mbahgg@163.com
  • 基金资助:

    中国石油大学(北京)科研基金(KYJJ2012 02 06)。

Diffusion Seepage Model for Fractured Horizontal Well
in Shale Gas Reservoir

Guo Xiaozhe1*, Zhou Changsha2   

  1. 1. College of Petroleum Engineering,China University of Petroleum(Beijing),Changping,Beijing 102249,China
    2. Northeast Petroleum Bureau,SINOPEC,Changchun,Jilin 130062,China
  • Online:2015-06-01 Published:2015-06-01

摘要:

针对页岩储层纳米孔隙中天然气扩散作用对压裂水平井产能有多大影响这一问题,开展了渗流数学模型建
立、求解及定量计算分析研究,研究中采用了三线性渗流机理、克努森扩散机理及扩散引起渗透率增加值公式,绘制了
不同孔隙直径下克努森数与储层压力关系图版,得到了可用于实际生产预测的单井产能方程,从孔隙大小、储层压力、
气藏深度等3 个方面进行了扩散作用的分析,给出了页岩气藏生产过程中需要考虑扩散作用的各指标阈值。结果表
明,在储层压力条件下,孔隙越小的储层,扩散作用对产能的影响越大,而对于较大孔隙的储层,当井底压力低于模型
中计算出的阈值时,扩散作用就不应该被忽略。

关键词: 页岩气藏, 扩散, 渗流, 水平井产能, 克努森系数

Abstract:

To determine the effect of gas diffusion affection in the shale gas reservoirs with the desorption-adsorption and
nano-scale pore on fractured horizontal well productivity analysis,we established the seepage mathematic model and analyzed
quantitatively the production. In the study,we used the three linear seepage mechanism,Knudsen diffusion mechanism and
diffusion of the added value of permeability formula to draw the relation chart of Knudsen number under different pore diameters
with reservoir pressure,and derived the single well productivity equation to be used for the actual production prediction.
Analysis of the diffusion of shale gas reservoir was carried out in 3 aspects,which are the pore size,reservoir pressure and gas
reservoir depth,and reference is given to consider the diffusion of various indicators. Results show that under the condition of
the reservoir pressure,the smaller the porosity of the reservoir,the greater the influence of diffusion effect is on capacity;and
for large pore reservoir,when the bottom hole pressure is lower than the threshold of the calculated in the model,the diffusion
effect should not be ignored.

Key words: shale gas reservoir, diffusion, porous flow, horizontal well production capacity, Knudsen coefficient