利用快中子散射截面定量评价砂泥岩储层含气饱和度的方法及应用

陆相砂岩和海相碳酸盐岩等致密气储层非均质性强,气水关系复杂,孔隙度低,定量评价含气性是储层评价必然需求.为建立含气储层饱和度的评价方法,通过研究非弹性散射伽马计数、快中子散射截面与含气饱和度响应关系,利用蒙特卡罗软件建立不同孔隙度和泥质含量等条件下井筒-储层模型,模拟非弹性散射伽马计数分布.结果表明,利用非弹伽马计数可...

Quantitative Evaluation of Gas Saturation in Sand-Shale Reservoir by Fast Neutron Cross Section and its Application

Tight gas reservoirs such as terrestrial sandstone and marine carbonate rock are characterized by strong heterogeneity, complex gas-water relationship, and low porosity. Quantitative evaluation of gas-bearing properties is an inevitable requirement for formation evaluation. Due to the hydrogen index and the fast neutron interaction process of gas, water and oil is different obviously, fast neutron cross-section (FNXS) has become a quantitative method for evaluating gas saturation. This paper uses Monte Carlo software to establish borehole and formation models under different porosity and shale content conditions, simulates the distribution of inelastic scattering gamma counts, and studies the relationship between inelastic scattering gamma counts, FNXS and gas saturation. The results show that FNXS can be characterized by inelastic gamma counts, and the shale content have influences on FNXS characterization and gas saturation response, the correction for shale are needed. The results of field examples show that FNXS can realize quantitative evaluation of gas saturation, and the interpretation results are consistent with open hole results. The research provides technical support for the quantitative evaluation of tight gas reservoirs.