基于三维地质建模的煤层气井产能特征分析

借助三维地质建模软件,基于寺河西区138口单采3号煤层的气井2007-2017年的产量数据,将研究区划分为A、B、C 3个区域,对比分析煤体结构平剖面分布特征与产能时空变化特征。结果表明:研究区发育原生结构为主,含少量构造煤,基本不含碎粒煤和糜棱煤;碎裂煤含量区域分布,以C区为中心,碎裂煤含量向A区和B区逐渐减少,C区>B区>A区;产能区域分布,平均日产气量A区>B区>C区,A区和B区域大部分气井产能可持续性较好,C区多分布产能衰减型煤层气井;发现碎裂煤含量虽然对煤层气井的早期产能有较大贡献但不利于产能的持续性,碎裂煤含量为18%左右的C区,早期产气量较高,衰减较快。

Analysis of Productivity Characteristics of Coalbed Methane Based on 3D Geological Modeling

Using the geological modeling software, based on the production data of 138 CBM wells in No.3 coal seam of western Sihe minefield from 2007 to 2017, the production capacity of the study area can be divided into three zones: A, B and C. The plane and profile characteristics of coal structure and the temporal and spatial variation characteristics of productivity were compared and analyzed. The results show that the study area is mainly composed of primary structure and contains a small amount of structure coal, It basically contains no broken grain structure coal and mylonite structure coal. Regional distribution of broken structure coal content is C>B>A. Take C as the center, the broken structure coal content gradually decreases to zone A and zone B. For the capacity distribution, the average daily CBM production is A>B>C. Most wells with good CBM production capacity are distributed in the A and B zones. The C-zone has a large distribution of production-attenuated CBM wells. Although the content of broken structure coal content has a great contribution to the early production capacity of CBM wells, it is bad to the sustainability of production capacity. In the C zone with broken structure coal content of about 18%, the early gas production is higher and the decay is faster.