泥质砂岩地层的粘土性质分析

地层中粘土的存在对测井解释结果起着十分重要的影响,是造成测井解释复杂性的重要原因之一.正确地分析地层中的粘土性质,有助于测井解释人员更加全面地进行泥质砂岩储层的油气评价.以粘土测井特征和中子-密度测井交会法为基础,对每个泥质砂岩资料点确定其粘土性质,按含水泥质砂岩模型计算地层粘土含量;用粘土的阳离子交换量与干粘土含氢指数的交会来识别粘土类型.实践证明,该方法对物性较差的低渗透储集层以及低电阻率油气层有优越性,但对含轻烃的地层不适用.

Components and Physicochemical Properties of Clay in Shaly Sand Formation

Clay has complicated mineral components and complex physicochemical properties. The components, contents and distributions of clay in formations may change obviously. So it has a great influence on log interpretation results, and it is one of the factors that causes log interpretation more complex. Correct analysis of the clay properties helps us more completely evaluate shaly sand reservoir. On the basis of log features of clay and neutron-density logging crossplot, clay properties at each shaly sand data point are determined, then the water-bearing shaly sand model is used to estimate the clay contents. CEC-IH plot is used to identify the clay types. Logging examples prove that this method is fit for lower permeable and resistive reservoir with poor petrophysical property, but not fit for light hydrocarbon formation.