自然伽马测井约束的火山岩储集层孔隙度计算方法

Porosity Calculation Method of Volcanic Reservoir Constrained by Natural Gamma Logging

高明 陈国军 张进 张啸 张帆

GAO Ming CHEN Guojun ZHANG Jin ZHANG Xiao ZHANG Fan

中国石油天然气股份有限公司新疆油田分公司勘探开发研究院，新疆乌鲁木齐　830013

Geophycial Research Institute of Research Institute of Exploration and Development of Xinjiang Oilfield Company, PetroChina Co. Ltd., Urumqi Xinjiang 830013, China

火山岩岩性复杂多变，不同岩性化学成分变化大，非均质性强，其骨架参数往往变化频繁，常规采用固定骨架参数计算孔隙度方法中，骨架参数往往很难确定，导致计算误差很大。文章针对火山岩储集层孔隙度评价难度大的问题，优选了与岩石骨架密度相关性好、对岩性变化反应敏感且成本低、实际容易获取的自然伽马测井值建立随深度变化的自然伽马连续变骨架模型来计算储集层孔隙度，该方法实现了火山岩孔隙度的连续定量表征，解决了孔隙度计算精度低的难题，在中拐凸起火山岩储集层孔隙度评价中取得了很好的应用效果。

The lithology of volcanic rocks is complex and changeable, and the chemical composition of different lithologies varies greatly, and the heterogeneity is strong. Its skeleton parameters often change frequently. In the conventional method of calculating porosity with fixed skeleton parameters, the skeleton parameters are often difficult to determine, resulting in great calculation errors. In view of the difficulty in evaluating the porosity of volcanic reservoirs, this article selects the natural gamma logging values which have good correlation with rock skeleton density, are sensitive to lithological changes, are low-cost, and are actually easy to obtain to establish natural gamma logging values that vary with depth. The gamma continuous variable framework model is used to calculate porosity of the reservoir. This method realizes continuous quantitative characterization of the porosity of volcanic rocks and solves the problem of low porosity calculation accuracy. A good application effect has been achieved in the porosity evaluation of volcanic reservoirs in Zhongguai Uplift.

国家油气勘探重大专项“准噶尔盆地致密气地质评价与勘探目标优选”（2016ZX05047-001-004）

https://doi.org/10.3969/j.issn.1008-2336.2021.04.043