延川南煤层气田低效井原因分析与措施优选

doi:10.13809/j.cnki.cn32-1825/te.2020.04.005

摘要/Abstract

摘要：

针对延川南深层煤层气田低产低效井占比高,低产原因复杂,难以达到预期开发效果的问题,以延川南煤层气田低产低效井为研究对象,通过开展地质工程一体化研究分析,结合煤层气开发实践经验,认为排采速度不合理导致煤储层渗流通道堵塞,储层改造不到位导致泄流面积小,低压区地层能量不足导致煤层气解吸受限这三大问题是延川南低效井低产的主要原因。针对低效原因分别开展了可控强脉冲解堵、体积压裂实现裂缝转向、氮气扰动疏通促解吸等增产措施。现场应用评价结果显示,这些措施均能实现不同程度的增产,其中体积压裂可以达到有效改善储层物性的目的,单井日增产气1 000~4 000 m ³,增产效果显著,是延川南煤层气田目前最为有效的增产措施。

关键词: 延川南, 煤层气, 低产低效, 增产措施, 体积压裂

Abstract:

The low-yield and low-efficiency wells in the deep coal seam gas field of South Yanchuan are of high proportion and the reasons for low-yield are complex, so that it is difficult to achieve the expected development effect. In order to solve these problems, taking the low-yield and low-efficiency wells in South Yanchuan CBM Gas Field as the research object, the integrated research and analysis of geological engineering have been carried out. Combined with the practical experience of CBM development, it is found that the unreasonable drainage rate leads to the blockage of coal reservoir seepage channels, the inadequate reservoir transformation results in a small discharge area, and the lack of formation energy in the low-pressure area leads to the limitation of coal bed methane desorption. These three problems are the main reasons for the production of low-efficiency wells in South Yanchuan. For the reasons of inefficiency, production stimulation measures such as controllable strong pulse deblocking, volume fracturing to achieve fracture steering, nitrogen disturbance dredging and desorption have been carried out. The results of field application evaluation show that these measures can achieve different degrees of production increase, among which volume fracturing can achieve the purpose of effectively improving the physical properties of the reservoir. The daily production of a single well is increased by 1 000~4 000 m ³. The effect of production increase is remarkable. It is the most effective means of increasing production in South Yanchuan CBM Field currently.

Key words: South Yanchuan, CBM（coalbed methane）, low-yield and low-efficiency, stimulation measure, volume fracture

中图分类号:

TE37

李鑫,肖翠,陈贞龙,金晓波. 延川南煤层气田低效井原因分析与措施优选[J]. 油气藏评价与开发, 2020, 10(4): 32-38.

LI Xin,XIAO Cui,CHEN Zhenlong,JIN Xiaobo. Analysis of low-efficiency wells in CBM gas field of South Yanchuan and optimization of measures[J]. Reservoir Evaluation and Development, 2020, 10(4): 32-38.

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压裂特征	主控地质因素	储层改造效果	生产特征	典型压裂曲线
排量小,施工压力偏低	原生裂隙较发育,滤失严重	裂缝缝长受限	稳产产量低,采出程度不足	图4a
破裂压力高,施工压力上升,停泵压力高,加砂困难	地应力高、渗透率低	支撑剂在近井地带堆积,储层未有效改造	单峰型排采曲线,稳产期短或者无稳产期,产水量低级	图4b

增产技术	低产条件	储层改造效果	日增产/m³	措施有效期	成功率/%	成本	综合评价
体积压裂	初次压裂改造效果不佳	好	1 000~4 000	超过2年	81	高	成本高,增产效果好
可控强脉冲解堵	保存条件好原生结构煤有高产生产历史近井筒堵塞	较好	1 000	6个月	50	低	技术适应性不高
氮气扰动	低压储层近井筒堵塞煤层气解吸受限	一般	400	持续有效	90	低	成本低,操作简单, 增产效果一般