陈博, 汤达祯, 林文姬, 李松, 钟广浩, 朱学光. 基于地质建模的保德Ⅰ单元煤层气井产能响应特征[J]. 煤田地质与勘探, 2020, 48(5): 53-63. DOI: 10.3969/j.issn.1001-1986.2020.05.007
引用本文: 陈博, 汤达祯, 林文姬, 李松, 钟广浩, 朱学光. 基于地质建模的保德Ⅰ单元煤层气井产能响应特征[J]. 煤田地质与勘探, 2020, 48(5): 53-63. DOI: 10.3969/j.issn.1001-1986.2020.05.007
CHEN Bo, TANG Dazhen, LIN Wenji, LI Song, ZHONG Guanghao, ZHU Xueguang. Geological modeling-based productivity response characteristics of the CBM well in Baode unitⅠ[J]. COAL GEOLOGY & EXPLORATION, 2020, 48(5): 53-63. DOI: 10.3969/j.issn.1001-1986.2020.05.007
Citation: CHEN Bo, TANG Dazhen, LIN Wenji, LI Song, ZHONG Guanghao, ZHU Xueguang. Geological modeling-based productivity response characteristics of the CBM well in Baode unitⅠ[J]. COAL GEOLOGY & EXPLORATION, 2020, 48(5): 53-63. DOI: 10.3969/j.issn.1001-1986.2020.05.007

基于地质建模的保德Ⅰ单元煤层气井产能响应特征

Geological modeling-based productivity response characteristics of the CBM well in Baode unitⅠ

  • 摘要: 煤层气资源条件及储层物性特征是煤层气勘探开发的基础,开展煤层气藏地质建模,厘清煤储层在空间上的展布特征,解释单井产能差异,可为煤层气选区、布井提供理论依据。以山西保德Ⅰ单元为研究对象,基于煤心含气量实测数据和试井渗透率测试,采用支持向量机算法(SVM)和变形F-S渗透率计算公式建立研究区含气量和渗透率反演模型,完成162口煤层气井含气量和渗透率测井数据的分析。进一步采用随机建模方法建立研究区含气量和渗透率模型,由模型计算结果表明:4+5号煤层的含气量为2.0~5.2 m3/t,平均3.3 m3/t,8+9号煤层含气量为2.4~9.2 m3/t,平均5.1 m3/t;4+5号煤层渗透率为(0.8~9.8)×10-3 μm2,平均6.1×10-3 μm2,8+9号煤层渗透率为(2.8~11)×10-3 μm2,平均7.3×10-3 μm2;保德Ⅰ单元总体表现为低含气量、高渗透率的煤层气藏开发单元。基于建立的地质模型,进一步分析研究区煤层气储层等效含气量、资源丰度、含气饱和度等平面展布规律,对比分析2口典型井(B1-X1和B1-X2)的地质条件,发现B1-X1井各项参数均优于B1-X2井。从过井剖面和生产曲线可以看出,影响两井产能差异的因素主要包括资源条件和储层物性条件,其中后者起决定性作用,B1-X1井条件明显优于B1-X2井。综合分析可以得出,渗透率差异是影响煤层气开采的关键参数,而煤层气资源丰度和吸附饱和度是评价煤层气井维持高产和长时间稳产的重要因素,煤层气开发前需查明煤储层主要地质条件和物性参数,为煤层气开发工程设计提供依据。

     

    Abstract: Coalbed methane resource conditions and reservoir physical conditions are the basis of CBM exploration and exploitation. The geological modeling of CBM reservoir was carried out to clarify the spatial distribution of coal reservoir, and explain the difference of single well productivity, which can provide theoretical basis for selection and well drilling. This paper took Baode unit I as research object. Based on the measured data of gas content and well test permeability, the inversion model of gas content and permeability in the study area was established by using support vector machine algorithm(SVM) and transformed F-S permeability calculation formula, and the gas content and permeability logging interpretation of 162 CBM wells were completed. Furthermore, the modeling of gas content and permeability were established by using stochastic modeling method. The modeling results show that the gas content of coal seam 4+5 was 2.0-5.2 m3/t, averaging 3.3 m3/t, the gas content of coal seam 8+9 was 2.4-9.2 m3/t, averaging 5.1 m3/t; the permeability of coal seam 4+5 was (0.8-9.8)×10-3 μm2, averaging 6.1×10-3 μm2, the permeability of coal seam 8+9 was (2.8-11)×10-3 μm2, averaging 7.3×10-3 μm2. In general, it is a CBM development unit with low gas content, high permeability. Planar distribution characteristics of equivalent gas content, resource abundance, and adsorption saturation of coal reservoir in study area were analyzed based on the established geological model. Then, the geological conditions of two typical wells(B1-X1 and B1-X2) were compared and analyzed, the results show that the parameters of well B1-X1 were better than those of well B1-X2. From the cross-well section and the production curve, it can be seen that the productivity difference between two wells mainly includes two aspects: one is resource condition, the gas content and resource abundance of well B1-X1 are better than those of well B1-X2, and the low adsorption saturation in well B1-X2 makes gas desorption more difficult. On the other hand, it is reservoir physical conditions. The permeability of well B1-X1 is better than that of well B1-X2, which is beneficial to the seepage of coalbed methane and forms a high yield. Among them, the difference in permeability is a key parameter that affects CBM exploitation, and CBM resource abundance and adsorption saturation are important factors for evaluating CBM wells to maintain high and long-term stable production.

     

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