利用核磁和密度测井资料综合评价火山岩气层

大庆深层火山岩储层岩石矿物成分多样,储层物性差,骨架对中子测井的影响甚至超过了流体的影响,常用的中子-密度孔隙度交会法识别气层效果很差。而核磁共振测井基本不受骨架影响,而密度-核磁共振孔隙度差值可以较好地反映储层含气饱满程度。提出了应用双孔隙度差值识别气水层。经试气结果证实,解释符合率提高了5%。以试气资料为基础,应用密度-核磁孔隙度差值和有效孔隙度等参数建立了气层分类标准,可以将气层为好、中、差三类,应用此标准可以合理进行气层产能预测。

Application of Nuclear magnetic resonance (NMR) and Density logging data for volcanic gas reservoir evaluation

Since the diversity and multiplicity of rock mineral composition cause poor reservoir physical property in Daqing deep volcanic reservoir, neutron log response from volcanic matrix mineral is even stronger than from fluid in the volcanic rocks. The normal neutron-density crossplot is unsuitable for identifying gas reservoir. Nuclear magnetic resonance (NMR) logging data basically are not affected by the rock matrix, therefore, the difference of double porosity between density and NMR can reflect the reservoir gas content. Here on the basis of the researches, gas-water layer recognition method by applying the dual porosity difference value is proposed. The gas testing results confirm that logging interpretation coincidence rates increase by 5 percentage points. Based on the gas test data, some parameters such as the dual porosity difference value and effective porosity , can be used to establish gas reservoir classification standards based on the reservoir productivity, which can divided gas reservoirs into three types for good, medium and poor. Further, this standard can be use for the gas productivity evaluation.