元素录井技术在渤中A区块潜山界面卡取中的应用

渤中A区块是一个断块型古潜山构造,上覆地层为沙一段、沙三段,潜山地层为古生界、太古界,由于岩性组合复杂,存在多种进山模式,给潜山界面卡取带来了困难。为准确识别潜山界面,研究了该区块几口进潜山探井,归纳出4种可能的进潜山模式;使用SPECTRO XEPOSⅢ型台式X射线荧光分析仪对该区块5口探井的岩屑样品进行测量,通过对700余个岩屑样品的元素录井数据研究,归纳出渤中A区块不同岩性的元素录井特征以及不同进山模式下的元素含量变化规律。在此基础上提出以(Ca+Mg)与(Si+Fe+Al)关系来识别古生界潜山界面以及使用K/Na值识别太古界潜山界面的思路,结合潜山界面附近微量元素含量变化趋势提出了“微量元素卡山法”。

Application of element logging in the determination of buried hill interfaces in Bozhong A Block

The Block A in Bozhong is a fault-block type buried hill with overlying strata of the First and Third Member of Shahejie Formation and the buried hill strata of Paleozoic and Archean.Due to the complex lithology combination,multiple modes of drilling exist,bringing difficulties to the determination of buried hill interfaces.For accurate determination of buried hill interfaces,several prospecting wells in the buried hill in this block are studied and 4 possible modes of buried hill drilling are summarized.SPECTRO XEPOSⅢtype desktop X-ray fluorescence analyzer is used to measure the cuttings samples of 5 prospecting wells in the block.Through the study of element logging data of more than 700 cuttings samples,the element logging characteristics of different lithologies in Bozhong A Block and the law of element content change under different drilling modes of buried hills are summarized,based on which the ideas of using the relationship of(Ca+Mg)and(Si+Fe+Al)to identify Paleozoic buried hill interfaces and using K/Na value to identify Archean buried hill interfaces are put forward.Combined with the trend of trace element content near the buried hill interfaces,a method of drilling with trace element is proposed.