摘要
煤层气藏精细描述、地质建模及数值模拟对煤层气开发方案的制定至关重要。为了进一步优化资源储量利用和提高采收效率,加快煤层气田产能建设,以鄂尔多斯盆地东缘煤层气开发超过10年的31.08 km^(2)开发单元为研究对象,结合静态地质资料和动态生产数据,对煤层气进行了三维地质建模和数值模拟,系统揭示了煤储层分布特征,明确了煤层气储量动用情况,提出微幅构造对煤层气剩余资源的开发策略。研究结果表明:(1)将3、4+5、6、7、8和9号共6套煤层划分为12个小层,实现了0.5 m厚度煤层垂向网格控制,有效区分了厚煤层垂向含气量等属性变化;(2)结合地质模型和气井开发效果,提出了正向高部位、正向低部位、平缓斜坡区和负向低部位共4种微幅构造控制的煤层气富集模式,对应不同的产气、产水和井底流压变化曲线;(3)在数值模型基础上进行产气历史拟合,研究区煤层气总体采出程度为14.7%,抽样上述4种微幅构造下的井组(平均6~7口井),其平均采出程度依次为32.5%、6.8%、7.4%和4.9%,显示不同构造区域产气效果差异显著。结论认为:(1)在高剩余煤层气含量区进行井网加密和低效井治理,针对3、6和7号未动用煤层合层开发,是实现该区煤层气持续稳产高产的关键;(2)在未来煤层气勘探开发中,应关注微幅构造约束的不同气井开发表现差异,优选甜点区段,提高煤层气开发经济效益。
The fine description,geological modeling and numerical simulation of coalbed methane(CBM)reservoirs are crucial for the design of CBM development plan.In order to further optimize the utilization of resource reserves,improve the recovery efficiency and enhance the productivity of CBM field,this paper presents CBM three-dimensional geological modeling and numerical simulation 2 using the static geological data and dynamic production data,with the 31.08 km CBM block along the eastern margin of the Ordos Basin,which has been developed for more than one decade,as an example.The results reveal the distribution characteristics of the coal reservoirs and clarify the production status of the CBM reserves.Finally,the strategies to develop the remaining CBM resources controlled by micro-amplitude structures are proposed.It is indicated that the division of 6 coal seams(No.3,No.4+5,No.6,No.7,No.8,and No.9)into 12 layer enables the vertical grid control of 0.5 m thick coal seam and the effective identification of vertical changes in the attributes of thick coal seam such as vertical gas content.Based on the geological model and the development effect of gas wells,the CBM enrichment models controlled by four kinds of micro-amplitude structures(i.e.positive high part,positive low part,gentle slope zone,and negative low part)are proposed,corresponding to different gas production,water production and bottom hole flowing pressure curves.The historical matching of gas production based on the numerical model shows that the overall degree of CBM reserve recovery in the study area is 14.7%,and the average degree of reserve recovery from the well groups(averagely 6 or 7 wells)sampled in the above mentioned four kinds of micro-amplitude structures is 32.5%,6.8%,7.4%and 4.9%,respectively,suggesting that the gas production effect varies significantly from area to area.In conclusion,well infilling and inefficient well treatment in the zones with high residual CBM content are crucial to sustainable,stable and high CBM production in the study area,especially to commingled development of unproduced No.3,No.6 and No.7 coal seams.In the future CBM exploration and development,it is necessary to consider the differences in the development performance of gas wells under the control of micro-amplitude structures,and select the optimal sweet spot zones/intervals to improve economic benefits of CBM development.
作者
李勇
李军辉
李永臣
刘光峰
张远
LI Yong;LI Junhui;LI Yongchen;LIU Guangfeng;ZHANG Yuan(College of Geoscience and Surveying Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;PetroChina Coalbed Methane Company Limited,Beijing 100724,China)
出处
《天然气工业》
北大核心
2025年第3期54-67,共14页
Natural Gas Industry
基金
国家自然科学基金项目“基于煤层气高效排采的煤粉凝聚—沉降机制研究”(编号:42072194)。
关键词
鄂尔多斯盆地
煤层气开发
精细描述
地质建模
数值模拟
微幅构造
成藏模式
Ordos Basin
Coalbed methane(CBM)development
Fine description
Geological modeling
Numerical simulation
Micro-amplitude structure
Hydrocarbon accumulation model
