深层中低煤阶储层煤层气含量测井计算方法

Logging Calculation Method for Coalbed Methane Content Medium and Low Rank Coal Reservoirs in Deep

深层中低煤阶煤层气作为目前的勘探热点,相应研究技术亟需突破,以往煤层气的研究方法均基于浅层建立,无法评价深层煤岩含气性特征。通过岩心实验及试气分析,发现深层煤岩具孔隙结构特征好、吸附气和游离气共存等特征。含气饱和度评价对深层煤岩研究至关重要,发现拟合的水层和吸附气层阻抗可很好解决气层定性识别和定量计算。对吸附气含气饱和度计算考虑了兰氏体积和兰氏压力温度校正,并在两个模型中加入含气饱和度及变骨架孔隙度参数,使吸附气和游离气的计算更加准确,为中低煤阶煤岩深层勘探提供测井技术支撑。

In deep,medium and low rank coalbed methane have become current exploration hotspots,and corresponding research technologies urgently need breakthroughs However,in the past,research on coalbed methane has been based on shallow methods,which cannot evaluate the gas bearing characteristics of deep coal formations.Through core experiments and gas testing analysis,it was found that the pore structure characteristics of deep coal rocks are good,with both adsorbed and free gas.The evaluation of gas saturation is crucial for deep coal rocks.It was found that fitting the impedance of water layers and adsorbed gas layers can effectively solve the qualitative identification of gas layers and the calculation.The calculation of adsorbed gas takes into account the correction of Lambert volume and Lambert pressure temperature,and adds gas saturation and variable skeleton porosity parameters to both models,making the calculation of adsorbed gas and free gas more accurate.This study provides logging technology support for deep exploration of medium and low rank coal and rock formations.