Fractured Horizontal Well Test Model for Shale Gas Reservoirs With Considering Multiple Stress Sensitive Factors

doi:10.7657/XJPG20210614

Abstract

Abstract:

Shale gas reservoir has multi-scale pore structures, so that shale gas flows in multiple ways including absorbing, diffusing and non-Darcy flow. Present shale gas flowing models only take the permeability and porosity of natural fractures as stress sensitivity factors, but experiments show that the diffusion coefficient is also sensitive to stress. To accurately predict and analyze shale gas reservoir and fluid parameters, it is necessary to establish a fractured horizontal well test model which should consider multi-scale pore structures and multiple gas flowing mechanisms, and it is also helpful to production performance analysis and subsequent development plan making. In this study, according to the multi-scale pore structures, and assuming that the shale gas reservoir is a dual medium with matrix and fractures, we built a fractured horizontal well test model which takes diffusion coefficient, and porosity and permeability of natural fractures as stress sensitive parameters, and analyzed the effects of fracturing scale and reservoir parameters on well test curve. The results show that fracturing parameters mainly affect early post-fracturing production, while reservoir parameters mainly affect late production. The model was applied in a typical shale reservoir block in China, and the modelling result well matched with the measured production data. It is a guiding reference to effective development of shale gas reservoirs.

Key words: shale gas reservoir, fractured horizontal well, stress sensitive effect, multiple flow mechanism, well test analysis, pore structure, dual medium, history matching

CLC Number:

TE37

LU Ting, WANG Mingchuan, MA Wenli, PENG Zeyang, TIAN Lingyu, LI Wangpeng. Fractured Horizontal Well Test Model for Shale Gas Reservoirs With Considering Multiple Stress Sensitive Factors[J]. Xinjiang Petroleum Geology, 2021, 42(6): 741-748.

Figures/Tables 7

Fig. 1.

Fig. 2.

Table 1

Definitions of mathematical model parameters for shale gas well test"

参数	表达式
无因次拟压力	$ψ D = π k fi h T sc p sc q sc T Δ ψ$ , $Δ ψ = ψ i - ψ$	（1）式,（2）式
无因次产量	$q D = q sc p sc T π K fi h T sc Δ ψ$	（3）式
无因次径向半径	$r D = r L ref$	（4）式
无因次控制半径	$r eD = r e L ref$	（5）式
无因次吸附气体积分数差	$V D = V i - V$	（6）式
无因次时间	$t D = K fi t μ gi ϕ C gi + 2 π K fi h q sc μ gi 1 - ϕ L ref 2$	（7）式
无因次基质孔隙半径	$r mD = r m r n$	（8）式
无因次渗透率应力敏感系数	$γ D = μ g Zγ p sc q sc T 2 p f π K fi h T sc$	（9）式
无因次裂缝线源产量	$q ˜ fD = q ˜ f q sc$	（10）式
第i段第j节无因次产量	$q D ij = q ij L ref q sc$	（11）式
第i段第j节裂缝无因次长度	$∆ L fD ij = ∆ L f ij L ref$	（12）式
储容比	$ω = ϕ C gi ϕ C gi + 2 π K fi h q sc μ gi 1 - ϕ$	（13）式
窜流系数	$λ = μ gi ϕ C gi + 2 π K fi h q sc μ gi 1 - ϕ L ref 2 D K fi r n 2$	（14）式
吸附系数	$σ = p sc q sc T π kh T sc ψ L V L ψ L + ψ i 2$	（15）式

Table 1

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

References 23

[1]	孙莹, 孙仁远, 刘晓强, 等. 基于竞争吸附的页岩气藏提高采收率机理[J]. 新疆石油地质, 2021, 42(2):224-231.
	SUN Ying, SUN Renyuan, LIU Xiaoqiang, et al. Mechanism of enhanced gas recovery in shale gas reservoirs based on competitive adsorption[J]. Xinjiang Petroleum Geology, 2021, 42(2):224-231.
[2]	黄小青, 韩永胜, 杨庆, 等. 昭通太阳区块浅层页岩气水平井试气返排规律[J]. 新疆石油地质, 2020, 41(4):457-463.
	HUANG Xiaoqing, HAN Yongsheng, YANG Qing, et al. Gas testing flowback rules of shallow shale gas horizontal wells in TY block of Zhaotong[J]. Xinjiang Petroleum Geology, 2020, 41(4):457-463.
[3]	陈奕羲, 张义平, 李波波, 等. 页岩气开采中储集层压力变化规律[J]. 新疆石油地质, 2018, 39(1):92-96.
	CHEN Yixi, ZHANG Yiping, LI Bobo, et al. Variations of reservoir pressure during shale gas production[J]. Xinjiang Petroleum Geology, 2018, 39(1):92-96.
[4]	贾爱林, 王军磊, 位云生, 等. 页岩气压裂水平井控压生产动态预测模型及其应用[J]. 天然气工业, 2019, 39(6):71-80.
	JIA Ailin, WANG Junlei, WEI Yunsheng, et al. A dynamic prediction model of pressure control production performance of shale gas fractured horizontal wells and its application[J]. Natural Gas Industry, 2019, 39(6):71-80.
[5]	曹学军, 王明贵, 康杰, 等. 四川盆地威荣区块深层页岩气水平井压裂改造工艺[J]. 天然气工业, 2019, 39(7):81-87.
	CAO Xuejun, WANG Minggui, KANG Jie, et al. Fracturing technologies of deep shale gas horizontal wells in the Weirong block,southern Sichuan basin[J]. Natural Gas Industry, 2019, 39(7):81-87.
[6]	沈骋, 郭兴午, 陈马林, 等. 深层页岩气水平井储层压裂改造技术[J]. 天然气工业, 2019, 39(10):68-75.
	SHEN Cheng, GUO Xingwu, CHEN Malin, et al. Horizontal well fracturing stimulation technology for deep shale gas reservoirs[J]. Natural Gas Industry, 2019, 39(10):68-75.
[7]	欧阳伟平, 孙贺东, 韩红旭. 致密气藏水平井多段体积压裂复杂裂缝网络试井解释新模型[J]. 天然气工业, 2020, 40(3):74-81.
	OUYANG Weiping, SUN Hedong, HAN Hongxu. A new well test interpretation model for complex fracture networks in horizontal wells with multi-stage volume fracturing in tight gas reservoirs[J]. Natural Gas Industry, 2020, 40(3):74-81.
[8]	OZKAN E, BROWN M, RAGHAVAN R, et al. Comparison of fractured horizontal-well performance in conventional and unconventional reservoirs[R]. SPE 121290, 2009.
[9]	HUANG Ting, GUO Xiao, CHEN Feifei. Modeling transient pressure behavior of a fractured well for shale gas reservoirs based on the properties of nanopores[J]. Journal of Natural Gas Science and Engineering, 2015, 23:387-398.
[10]	SANG Yu, CHEN Hao, YANG Shenglai, et al. A new mathematical model considering adsorption and desorption process for productivity prediction of volume fractured horizontal wells in shale gas reservoirs[J]. Journal of Natural Gas Science and Engineering, 2014, 19:228-236. doi: 10.1016/j.jngse.2014.05.009
[11]	DENG Qi, NIE Renshi, JIA Yonglu, et al. A new analytical model for non-uniformly distributed multi-fractured system in shale gas reservoirs[J]. Journal of Natural Gas Science and Engineering, 2015, 27:719-737.
[12]	TAO Honghua, ZHANG Liehui, LIU Qiguo, et al. An analytical flow model for heterogeneous multi-fractured systems in shale gas reservoirs[J]. Energies, 2018, 11:3 422-3 440. doi: 10.3390/en11123422
[13]	张跃磊, 李大华, 郭东鑫. 页岩气储层压裂改造技术综述[J]. 非常规油气, 2015, 2(1):76-82.
	ZHANG Yuelei, LI Dahua, GUO Dongxin. Overview of shale gas reservoir fracturing technology[J]. Unconventional Oil & Gas, 2015, 22(1):76-82.
[14]	ZHAO Yulong, ZHANG Liehui, ZHAO Jinzhou, et al. “Triple porosity” modeling of transient well test and rate decline analysis for multi-fractured horizontal well in shale gas reservoirs[J]. Journal of Petroleum Science and Engineering, 2013, 110:253-262. doi: 10.1016/j.petrol.2013.09.006
[15]	WANG Haitao. Performance of multiple fractured horizontal wells in shale gas reservoirs with consideration of multiple mechanisms[J]. Journal of Hydrology, 2014, 510:299-312. doi: 10.1016/j.jhydrol.2013.12.019
[16]	TIAN Leng, XIAO Cong, LIU Mingjin, et al. Well testing model for multi-fractured horizontal well for shale gas reservoirs with consideration of dual diffusion in matrix[J]. Journal of Natural Gas Science and Engineering, 2014, 21:283-295. doi: 10.1016/j.jngse.2014.08.001
[17]	GUO Chaohua, XU Jianchun, WU Keliu, et al. Study on gas flow through nano pores of shale gas reservoirs[J]. Fuel, 2015, 143:107-117. doi: 10.1016/j.fuel.2014.11.032
[18]	杜殿发, 张耀祖, 张莉娜, 等. 页岩气藏渗流机理研究进展与展望[J]. 非常规油气, 2021, 8(3):1-9.
	DU Dianfa, ZHANG Yaozu, ZHANG Lina, et al. Research progress and prospect of seepage mechanism in shale gas reservoirs[J]. Unconventional Oil & Gas, 2021, 8(3):1-9.
[19]	LIU Jia, WANG J G, GAO Feng, et al. Flow Consistency between non-Darcy flow in fracture network and nonlinear diffusion in matrix to gas production rate in fractured shale gas reservoirs[J]. Transport in Porous Media, 2016, 111:97-121. doi: 10.1007/s11242-015-0583-9
[20]	JAVADPOUR F, FISHER D, UNSWORTH M. Nanoscale gas flow in shale gas sediments[J]. Journal of Canadian Petroleum Technology, 2007, 46(10):55-61.
[21]	LU Ting, LI Zhiping, LAI Fengpeng, et al. Blasingame decline analysis for variable rate/variable pressure drop:a multiple fractured horizontal well case in shale gas reservoirs[J]. Journal of Petroleum Science and Engineering, 2019, 178:193-204. doi: 10.1016/j.petrol.2019.03.036
[22]	CELIS V, SILVA R, RAMONES M, et al. A new model for pressure transient analysis in stress sensitive naturally fractured reservoirs[R]. SPE 23668, 1994.
[23]	WEI Mingqiang, DUAN Yonggang, DONG Mingzhe, et al. Blasingame decline type curves with material balance pseudo-time modified for multi-fractured horizontal wells in shale gas reservoirs[J]. Journal of Natural Gas Science and Engineering, 2016, 31:340-350. doi: 10.1016/j.jngse.2016.03.033