高全烃背景值下油气异常显示识别

Oil-gas abnormal identification under the condition of high total hydrocarbon background value

受上覆高压油气层或有机添加剂影响,气测录井经常出现较高的全烃背景值,高背景值的出现不仅湮没了低气油比油层显示,还产生一些假异常,给解释评价工作带来不少困难。该文针对这种特殊情况,如何去伪存真识别真显示进行了一些研究工作,摸索出了几种特殊的方法,分别为①中、高气油比油层采用基值剔除法;②低、特低气油比油层采用C1相对含量法和绝对含量法;③低气油比、特低C1油层采用C3含量法。经实际应用,效果较好。

Affected by overlying high pressure oil-gas beds and organic additive, the higher total hydrocarbon background values would often appeared in gas logging, the appearance of which not only annihilated low GOR oil bed shows, but also produced some false anomaly, so bring many difficulties to interpretation and evaluation job. In view of this special situation, the paper made some studies on how to get rid of the false and retain the true, and found out a few special methods, which separately were the background value rejecting method for medium and high GOR oil beds, the method of C_1 relative content and absolute content for low and especially low GOR oil beds and the method of C_3 content for low GOR and especially low C_1 oil beds. Through practical application, the above methods obtained the good results.