彭丽莎, 张毅敏, 熊威, 赵丹, 罗凯. 四川筠连地区高阶煤煤层气井解堵技术及应用[J]. 煤田地质与勘探, 2021, 49(5): 132-138. DOI: 10.3969/j.issn.1001-1986.2021.05.014
引用本文: 彭丽莎, 张毅敏, 熊威, 赵丹, 罗凯. 四川筠连地区高阶煤煤层气井解堵技术及应用[J]. 煤田地质与勘探, 2021, 49(5): 132-138. DOI: 10.3969/j.issn.1001-1986.2021.05.014
PENG Lisha, ZHANG Yimin, XIONG Wei, ZHAO Dan, LUO Kai. De-blocking technology and application of high-rank CBM well in Junlian region in Sichuan Province[J]. COAL GEOLOGY & EXPLORATION, 2021, 49(5): 132-138. DOI: 10.3969/j.issn.1001-1986.2021.05.014
Citation: PENG Lisha, ZHANG Yimin, XIONG Wei, ZHAO Dan, LUO Kai. De-blocking technology and application of high-rank CBM well in Junlian region in Sichuan Province[J]. COAL GEOLOGY & EXPLORATION, 2021, 49(5): 132-138. DOI: 10.3969/j.issn.1001-1986.2021.05.014

四川筠连地区高阶煤煤层气井解堵技术及应用

De-blocking technology and application of high-rank CBM well in Junlian region in Sichuan Province

  • 摘要: 四川筠连地区乐平组煤层为低孔、低渗的高阶煤储层。部分煤层气井在生产过程中产气量出现快速下降,严重制约了煤层气井的开发效益。结合排采、水化学、检泵等生产动态信息系统分析煤层气井产气量下降的原因,认为煤层结垢与煤粉堵塞裂缝通道是产气量下降的主要原因。针对堵塞问题,对筠连地区煤层气区块开展了酸洗、水力震荡、等离子脉冲、注水等解堵工艺措施试验。现场排采动态表明,酸洗与等离子脉冲具有较好的增产效果。酸洗主要针对结垢的井,通过将酸液注入井筒,与井筒和近井筒地带无机垢充分反应,以达到解除井筒和近井筒地带通道堵塞的目的,酸洗措施成功率高,投入产出比1∶1.8,是区域内首选低成本有效性措施;等离子脉冲解堵主要针对煤粉和结垢井,通过物理震荡的方式粉碎堵塞物,然后通过洗井将堵塞物携带出井筒,从而实现解堵,实施后增产效果较佳,煤层气产量增产达130%,但因实施数量有限,区域适应性还有待评价;水力震荡、注水等解堵措施主要是针对煤粉堵塞井,通过水力冲击以及水力循环的方式带出煤粉以达到解堵的效果,但该措施本身也会造成储层激动,容易产生副作用,措施整体有效率不到30%,增产效果不明显。上述4种解堵措施均有其适应条件,需要根据堵塞原因,采取与之适应的措施才能获得最佳的解堵效果。研究成果可为我国同类煤层气井解堵、增产提供一定的借鉴。

     

    Abstract: The coal seams of Leping Formation in Junlian area are high-rank coal reservoir with low porosity and low permeability. The gas production of some coalbed methane wells decreases rapidly in the production process, which seriously restricts the benefit development of coalbed methane wells. Combined with the production data such as drainage, hydrochemistry and pump inspection, this paper analyzes the reasons for the decline of gas production. The main reasons for the decline are coal scaling and coal fines blockage. Targeted measures such as acid pickling, hydraulic shock, plasma pulse and water injection are carried out to remove the blockage. The results show that acid pickling and plasma pulse have good effect on increasing gas production. Pickling is mainly aimed at scaling wells. By injecting acid into the wellbore and fully reacting with inorganic scale in the wellbore and near wellbore zone, the purpose of removing blockage of the passage in the wellbore and near wellbore zone is achieved. The success rate of pickling measures is high, and the input-output ratio is 1︰1.8, so it is the first choice of low-cost effective measures in the area. Pulse plugging is also aimed at coal fine output and scaling wells, and it has a good effect for increasing gas production by 130% after implementation. However, due to the limited number of implementation, the regional adaptability remains to be evaluated. The measures such as hydraulic shock and water injection are mainly aimed at wells blocked by coal fines. Coal fines are taken out to remove blockage by means of hydraulic shock and hydraulic circulation. However, such measures themselves will also cause formation stress change, which is prone to cause the negative effect. The overall effective rate of hydraulic shock and water injection measures is less than 30% and the effect of increasing production is not obvious. The above four de-blocking measures all have their own adaptive conditions, so it is necessary to take appropriate measures according to the causes of blockage to obtain the best de-blocking effect. The research results in this paper can provide some reference for de-plugging and increasing production of similar coalbed methane wells in China.

     

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