碳酸盐岩定量分析技术及其在四川盆地录井工作中的应用

Quantitative analysis of carbonates and its application to logging in the Sichuan Basin

碳酸盐岩储层是四川盆地油气勘探的主要层位之一。一直以来,录井过程中对碳酸盐岩岩屑的鉴别主要依据人为经验、化学分析和碳酸盐岩分析仪。近年来,由于勘探的需要,钻井大提速主要使用PDC钻井、气体钻井新技术新工艺,四川盆地钻速大幅度提高,给录井工作中的岩屑鉴别增加了困难,影响了岩屑录井剖面质量和碳酸盐岩白云岩储层的发现。传统的碳酸盐岩鉴别法满足不了现代钻井工艺条件下的录井要求,为此研发了新型碳酸盐岩分析技术,在现场能够比较准确地分析出岩石的主要成分如白云石、方解石和酸不溶物的含量,用于岩性定名、地层对比和白云岩储层的发现。该项新技术主要是采用质量分析法,和过去碳酸盐岩仪的压力法相比,具有数据准确、分析时间短的优势。通过在四川盆地的应用,取得了良好的效果。因此,对碳酸盐岩定量分析新技术的原理、应用条件、定量解释方法和应用效果进行了介绍,评价了该技术的应用前景。

Carbonate reservoirs are the major targets of exploration in the Sichuan Basin. Previous logging identification of carbonate rock debris is mainly based on experiences of logging service personnel, chemical analysis and carbonates analyzer. In recent years,innovative PDC drill bits and gas drilling technologies have been widely applied in exploration, thereby to greatly increase the drilling rate. However, the sharp increase of drilling rate also put much pressure on rock debris identification, influencing the quality of sample log and the discovery of dolostone reservoirs. When traditional carbonates identification methods can not meet the requirements of logging during drilling operation with modern techniques, we develop a new carbonates analysis technology which can relatively accurately measure the contents of main rock compositions such as dolomite, calcite and acid non-soluble substances on well sites. The measured results can be used for lithology identification and stratigraphic correlation so as to find dolostone reservoirs. In comparison with the previous pressure method of carbonate analyzer, the new technology mainly based on mass analysis has the advantages of high accuracy and efficiency. It has been successfully applied in the Sichuan Basin. This paper introduces its principles, conditions of application, quantitative interpretation methods and application effects, and evaluates its prospect of popularization.