疏松砂岩储层出砂分析测井评价新方法

A new method of log evaluation for sand production in unconsolidated sandstone reservoirs

渤海油田新近系疏松砂岩储层分布广泛,其显著的出砂特点为油田开发生产带来巨大风险。传统出砂分析方法受限于地应力计算精度,现场应用效果不理想。在渤海蓬莱X油田新近系疏松砂岩岩心实验数据分析基础上,利用岩石物性参数建立了对研究区适用性较好的内聚力和内摩擦角计算方法;结合疏松砂岩储层微观出砂机理分析,应用莫尔-库伦破裂理论构建了内聚力和内摩擦角相结合的测井评价临界生产压差图版。蓬莱X油田60余口井的现场应用表明,本文新方法出砂预测成功率大于80%,为现场提供了一种简单、快速进行出砂层位识别和风险分析的手段。

The unconsolidated sandstone reservoirs in the Neogene are widely distributed in Bohai oilfield.Its remarkable characteristic of sand production poses great risks for the oilfield development and production.Conventional method of sand production analysis was limited by the low precision of in-situ stress calculation,and the actual application was not satisfactory.Based on the core experimental data analysis of the Neogene unconsolidated sandstone of PL X oilfield in Bohai sea,new methods for calculating cohesion and internal friction angle with favorable applicability were established by using petrophysical parameters.Combining with the analysis of micro-sanding mechanism in unconsolidated sandstone reservoirs,a new critical production pressure drawdown chart of log evaluation was introduced by integrating both cohesion and internal friction angle based on Mohr-Coulomb fracture theory.The field application of more than 60 wells in PL X oilfield shows that the success rate of sand production prediction in this paper is higher than 80%.The new method provides a simple and quick means of layers identification and risk analysis in sand production.