基于现代产量递减分析的延川南煤层气田剩余气分布数值模拟研究

doi:10.13809/j.cnki.cn32-1825/te.2020.04.004

摘要/Abstract

摘要：

针对煤层气井产量差异大、储量动用程度不均衡的问题,基于延川南煤层气田生产数据及开发成果,综合考虑煤层气吸附解吸以及煤储层基质收缩效应,采用修正后的现代产量递减分析法以及煤层气数值模拟法对气井储量动用情况、剩余气分布规律以及开发潜力开展了研究。结果表明,300 m×350 m井网不能有效动用煤层气储量,平面上动用程度差异较大,研究区西北部动用程度较低,平均泄流半径仅为78 m,较低于东南部开发动用,数值模拟研究表明西北部面积2.8 km ²剩余气地质储量达2.53×10 ⁸m ³,采出程度仅为4.2 %;从影响因素上来看,研究区剩余气类型主要为井控未动型、井网不完善型两种类型,针对井控未动型可采用加密井网或重复压裂增效,数模显示采出程度可提高9.6 %,而井网不完善型则需进一步完善井网促进面积降压。该研究成果为气田后期开发调整部署及措施挖潜提供了依据。

关键词: 煤层气, 剩余气分布, 现代产量递减分析, 数值模拟, 开发潜力

Abstract:

Large difference in productivity and unbalanced development of OGIP（original gas in place） are common issues during CBM production. Based on the production history of south Yanchuan coalbed methane reservoir and A-PDA（advanced production data analysis） method, numerical simulation is employed to study the depressuring degree and the distribution of residual gas as well as the development potential considering the sorption and matrix shrinkage effects. The results show that the 300 m×350 m rectangular well pattern cannot effectively utilize the reserves of CBM, and there is a great difference in the recovery degree of OGIP horizontally. The recovery degree in the northwest is low, and the average drainage radius is only 78 m, which is lower than that in the southeast. Through the mathematical model analysis, the residual gas in place in the northwest parts with the area of 2.8 km ² reached 2.53×10 ⁸ m ³, but the recovery degree is only 4.2 %. From the perspective of influencing factors, the typical remaining gas in the study area are mainly undeveloped well control type and imperfect well pattern type. Infilling well pattern or repeated fracturing can be used for undeveloped well control type, the former can make a raise in recovery degree by 9.6 % according to the numerical model, while for the latter, the well pattern needs to be further improved to promote area pressure reduction. The research provides a guild-line for adjustment disposition and measures.

Key words: CBM（coalbed methane）, residual gas distribution, A-PDA（advanced production data analysis）, numerical simulation, development potential

中图分类号:

TE328

肖翠,王伟,李鑫,杨小龙. 基于现代产量递减分析的延川南煤层气田剩余气分布数值模拟研究[J]. 油气藏评价与开发, 2020, 10(4): 25-31.

XIAO Cui,WANG Wei,LI Xin,YANG Xiaolong. Numerical simulation of residual gas distribution in CBM gas field of south Yanchuan based on advanced production data analysis[J]. Reservoir Evaluation and Development, 2020, 10(4): 25-31.

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参数	取值
初始气藏压力/MPa	9.4 ~ 10.6
煤层厚度/m	4.5 ~ 5.5
孔隙度/%	2 ~ 6
煤层渗透率/10^-3 μm²	0.01 ~ 1.4
气藏温度/℃	42
含气饱和度/%	70
兰氏体积/（m³·t^-1）	37.31
兰氏压力/MPa	4.5
气体综合压缩系数/MPa^-1	0.111
裂缝系统孔隙压缩系数/MPa^-1	1.03×10^-3
煤岩密度/（g·m^-3）	1.4
气体粘度/（mPa·s）	0.014 3
杨氏模量/MPa	3 068
泊松比	0.35

井号	日产气/m³	井底流压/MPa	A-G			Blasingame			NPI			Transient			平均
井号	日产气/m³	井底流压/MPa	渗透率/ 10^-3μm²	有效半缝长/m	泄流面积/10⁴m²	渗透率/10^-3μm²	有效半缝长/m	泄流面积/10⁴m²	渗透率/10^-3μm²	有效半缝长/m	泄流面积/10⁴m²	渗透率/10^-3μm²	有效半缝长/m	泄流面积/10⁴m²	渗透率/10^-3μm²	有效半缝长/m	泄流面积/10⁴m²
A-1	1 104	2.2	0.16	53	4.5	0.23	58	4.8	0.33	55	4.4	0.25	60	4.2	0.24	56.6	4.5
A-2	3 759	1.1	0.32	82	6.0	0.31	91	5.9	0.30	87	5.8	0.30	86	5.6	0.31	86.5	5.8
A-3	930	1.2	0.21	51	3.5	0.12	53	3.7	0.19	57	3.9	0.22	56	3.8	0.19	54.3	3.7
A-4	2 278	1.2	0.20	75	5.2	0.23	72	5.0	0.40	81	5.5	0.14	84	4.8	0.24	78.0	5.1
A-5	3 243	1.2	0.20	65	4.2	0.13	72	4.0	0.30	65	3.9	0.10	64	3.8	0.18	66.5	4.0
A-6	2 937	1.2	0.29	63	7.0	0.20	58	6.5	0.17	62	6.8	0.30	61	6.5	0.24	61.0	6.7
A-7	2 842	1.1	0.12	55	3.5	0.06	56	3.6	0.20	49	3.2	0.16	51	3.8	0.14	52.8	3.5
A-8	2 122	1.2	0.35	77	6.1	0.34	84	6.5	0.29	73	6.0	0.40	86	5.9	0.35	80.0	6.1
A-9	305	1.1	0.10	57	3.0	0.13	50	2.8	0.08	56	2.5	0.06	55	3.0	0.09	54.5	2.8
A-10	201	1.0	0.03	36	1.8	0.03	38	2.0	0.04	32	1.6	0.02	34	1.7	0.03	35.0	1.8