沁端区块煤层气开发方案研究

Coalbed Methane Reservoir Development Scheme of Qinduan Block

通过基础地质特征、开发层系划分、开采井井型确定、井网优选、合理井距计算等要素分析,对沁端区块煤层气开发方案进行研究。沁端区块主力煤层为3号和15号,区块地质构造简单,煤储层非均质性较弱,两套煤层流体性质、压力系统一致、生产能力相仿,可作为一套开发层系,适合采用水平井开采,井网部署可参照五点布井法。通过开发层系划分,优选的开采井型、井网及井距的分析,设计出4种开发方案,根据国内现有的开采技术水平,并通过数值模拟,对4种开发方案的累计产气量、采收率、经济效益等进行预测和评价,确定145口直井和20口水平井两种井型搭配投入生产,总支出较少且采收率较高,最终采收率达可42.25%,整体利润较大,是沁端区块煤层气最佳的开发方案。

We analyzed basic geological features, division of development strata, mining well type determination, well pat- tern selection, rational well spacing calculation and other factors, and probed into the CBM development schemes for Qinduan Block. No. 3 coal bed and No. 15 coal bed are major reservoirs of Qinduan Block, with simple geological structure, weakly homogeneous reservoir, fluid property of two sets of coal beds, consistent pressure system, and similar productivity. They can be seen as one set of development series of strata. Horizontal mining method could be adopted, and five-spot method could be employed for well pattern deployment. Through division of development strata and analysis on optimized mined well types, well pattern and well spacing, we drew four development schemes. According to domestic mining technology, and through numerical simulation, we evaluated the total gas production, recovery, and economic results, etc. , and determined arrangement of two types of wells--145 vertical wells and 20 horizontal wells. Total cost was reduced, and recovery was higher, with the ultimate recovery reaching 42. 25% and huger benefits. The new development schemes are the best for CBM development in Qinduan Block.