张雷,徐凤银,李子玲,等. 煤层气田单/合层开发影响因素分析及应用−以保德区块为例[J]. 煤田地质与勘探,2022,50(9):68−77. DOI: 10.12363/issn.1001-1986.21.12.0865
引用本文: 张雷,徐凤银,李子玲,等. 煤层气田单/合层开发影响因素分析及应用−以保德区块为例[J]. 煤田地质与勘探,2022,50(9):68−77. DOI: 10.12363/issn.1001-1986.21.12.0865
ZHANG Lei,XU Fengyin,LI Ziling,et al. Analysis on influencing factors of single/multi-layer development of coalbed methane field: A case study of Baode Block[J]. Coal Geology & Exploration,2022,50(9):68−77. DOI: 10.12363/issn.1001-1986.21.12.0865
Citation: ZHANG Lei,XU Fengyin,LI Ziling,et al. Analysis on influencing factors of single/multi-layer development of coalbed methane field: A case study of Baode Block[J]. Coal Geology & Exploration,2022,50(9):68−77. DOI: 10.12363/issn.1001-1986.21.12.0865

煤层气田单/合层开发影响因素分析及应用以保德区块为例

Analysis on influencing factors of single/multi-layer development of coalbed methane field: A case study of Baode Block

  • 摘要: 鄂尔多斯盆地东缘保德区块是国内中−低阶煤中首个完成5亿m3产能建设并达产的煤层气田,在中国煤层气行业树立了标杆地位。在区块开发过程中,大多数煤层气开发井两套主力煤层合层开发取得了良好的效果,均优于单层开发;但在局部区域,在相同的开发技术工艺条件下,部分开发井合层开发效果不理想,单层开发优于合层开发。从保德区块各煤层气单/合层开发井的地质条件、气藏特征及产气效果3个方面对区块进行整体评价,研究认为,煤层气地质条件是控制单/合层开发效果的根本因素,控制气藏特征并与之共同影响产气效果。根据主要量化指标确定单/合层排采效果差异性,优选1套确定煤层气井单/合层开发优选的量化评价指标,即对于2套煤层原始地层压力差值不超过0.6 MPa、临界解吸压力差值小于0.4 MPa、渗透率差值在2×10−3 μm2以内,适合煤层气合层开发。在此基础上,指出下步区域及层系开发调整的重点区域,即区块1单元西部、2单元中西部优先单层开发8+9号煤层更有利,3单元南部优先单层开发4+5号煤层更有利;针对区块8+9号煤层剩余未动用储量多的区域,可通过调整层系开发顺序的方式,即暂时封堵4+5号煤层、优先开发8+9号煤层。研究成果对多层系煤层气田高效开发具有重要指导意义。

     

    Abstract: Baode Block in the eastern margin of Ordos Basin is the first coalbed methane field of middle-low rank coal with 500 million cubic meters of production capacity constructed and reached in China, and it is also a benchmark in the coalbed methane industry there. During the development of Baode Block, good results are obtained by the commingled development of two sets of main coal layers, which are better than that of single-layer development. However, poor development result is obtained locally in the commingled development of some wells under the same development conditions, which is poorer than that of single-layer development. Therefore, overall evaluation was performed for Baode Block from the points of geological conditions, gas reservoir characteristics and gas production of the single/multi-layer commingled development wells in each coal bed. According to the research, the geological conditions of coalbed methane are the essential factors to control the result of single/multi-layer commingled production, which will control the CBM reservoir and influence the CBM production together with the reservoir. Herein, the difference in the effect of single/multi-layer drainage was determined in accordance with the main quantitative indicators, and the optimal quantitative evaluation indicators of single/multi-layer development of coalbed methane were determined by preferentially selecting 1 set of coal layers. That is, the original formation pressure difference is not more than 0.6 MPa, the critical desorption pressure difference is less than 0.4 MPa, and the permeability difference is within 2×10−3 μm2 for the two sets of coal layers, which are suitable for commingled development of coalbed methane. On this basis, the region for development in next step and the key areas for development adjustment were pointed out. Definitely, it is more favorable to give priority to the single-layer development for No.8+9 coal layers in the western part of Unit 1 and in the central and western parts of Unit 2 in the block, as well as No.4+5 coal layers in the southern part of Unit 3. In view of the area with a large amount of undeveloped reserves in No.8+9 coal layers in the block, No.8+9 coal layers may be developed in priority by adjusting the development sequence of layers, with No.4+5 coal layers blocked temporarily. In general, the results of this research are of great significance for the guidance of efficient development of coalbed methane fields with multiple bed series.

     

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