﻿ 应力敏感页岩气藏压力动态分析 Pressure Dynamic Analysis of Stress-Sensitive Shale Gas Reservoir

Open Journal of Nature Science
Vol.04 No.03(2016), Article ID:18364,6 pages
10.12677/OJNS.2016.43038

Pressure Dynamic Analysis of Stress-Sensitive Shale Gas Reservoir

Ziyu Zhao, Ermeng Zhao

College of Petroleum Engineering, Northeast Petroleum University, Daqing Heilongjiang

Received: Aug. 1st, 2016; accepted: Aug. 19th, 2016; published: Aug. 22nd, 2016

ABSTRACT

Based on the theory of Langmuir isothermal adsorption, the mathematical model of double media seepage in fractured shale gas reservoirs which considers stress sensitivity under different boundary conditions is established in this paper. Taking the strong nonlinearity of the model into account, desorption effect can be considered as the increase of isothermal compressibility of matrix during the resolution to decrease the degree of nonlinearity of the model. The analytical solution of the mathematical model in Laplace space is obtained by means of Laplace transformation and perturbation transformation. Finally, pressure transient curves are drawn with the aid of computer programs, and its characteristics have been analyzed, and parameter sensitivity analysis for the contributing factors affecting the dynamic curve of pressure also has been done. The results can provide scientific basis for well test analysis of shale gas reservoirs.

Keywords:Shale Gas, Pressure Behavior, Stress Sensitivity

1. 引言

2. 数学模型

2.1. 数学模型的建立

(1)

(2)

(3)

2.2. 数学模型的求解

(4)

(5)

(6)

1) 无限大外边界

(7)

2) 圆形封闭边界

(8)

3) 圆形定压外边界：

(9)

(10)

3. 页岩气压力动态影响因素分析

3.1. 应力模数的影响

3.2. 外边界类型的影响

3.3. Langmuir体积的影响

Figure 1. Dynamic curve of pressure under different permeability modulus

Figure 2. Dynamic curve of pressure of shale gas reservoirs with different boundary types

Figure 3. Dynamic curve of pressure under different Langmuir volume

4. 结论

1) 建立并求解了考虑应力敏感作用的裂缝性页岩气藏在不同边界条件下的双重介质渗流数学模型。

2) 页岩气藏应力敏感作用的存在使得气藏压力降落速度变快，并使得单井控制程度有限，所以对于应力敏感性较强的储层，要合理控制压差，以防对储层造成损害。

3) 不同的外边界条件前期压力动态曲线是一样的，只是在流动阶段后期有不同的表现。供给半径的大小只影响外边界反映阶段，供给半径越大，探测到外边界的时间越晚。

4) 随着Langmuir体积的不断增大，在压力导数曲线上表现为过渡段的“凹子”变深，补偿井底压力损失明显，井底压力降低缓慢。

Pressure Dynamic Analysis of Stress-Sensitive Shale Gas Reservoir[J]. 自然科学, 2016, 04(03): 327-332. http://dx.doi.org/10.12677/OJNS.2016.43038

1. 1. 段永刚, 魏明强, 李建秋, 唐艳. 页岩气藏渗流机理及压裂井产能评价[J]. 重庆大学学报, 2011, 34(4): 62-66.

2. 2. 李建秋, 曹建红, 段永刚, 何玮. 页岩气井渗流机理及产能递减分析[J]. 天然气勘探与开发, 2011, (2): 34-37, 81.

3. 3. 于荣泽, 张晓伟, 卞亚南, 李阳, 郝明祥. 页岩气藏流动机理与产能影响因素分析[J]. 天然气工业, 2012, 32(9): 10-15, 126.

4. 4. John, L.W., Ted, W.A. and Gatens III, J.M. (1990) An Analytical Model for History Matching Naturally Fractured Reservoir Production Data. SPE 18856.

5. 5. King, G.R. (1993) Material-Balance Techniques for Coal-Seam and Devonian Shale Gas Reservoirs with Limited Water Influx. Reservoir Engineering, 8, 67-72. http://dx.doi.org/10.2118/20730-PA

6. 6. Ozkan, E. and Raghavan, R. (2009) Modeling of Fluid Transfer from Shale Matrix to Fracture Network. SPE 134830- MS.

7. 7. 段永刚, 李建秋. 页岩气无限导流压裂井压力动态分析[J]. 天然气工业, 2010, 30(3): 26-29, 116.

8. 8. 尹虎, 王新海, 刘洪, 等. 考虑启动压力梯度的页岩气藏数值模拟[J]. 天然气与石油, 2012, 30(4): 43-45.

9. 9. Pedrosa, Jr. (1986) Pressure Transient Response in Stress-Sensitive Formations. SPE 15115.

10. 10. 同登科, 周德华, 陈钦雷. 具有应力敏感于地层渗透率的分形油气藏渗流问题的近似解吸研究[J]. 石油勘探与开发, 1999, 26(3): 53-57.