Rúguǒ / hányóu / yáncéng / jùlí / dìbiǎo / jiào / qiǎn / kāicǎi / chéngběn / kěnéng / xiāngduì / jiào / dī如果含油岩层距离地表较浅,开采成本可能相对较低。If an oil-bearing rock layer is relatively close to the surface, extraction costs may be comparatively low.