Which lavender oil will get rid of insomnia?

Not to my knowledge! I have not found scientific studies that support this, but if it works for you, harmless. And good.
Aromatherapy. Aromatherapy w lavender oil can be helpful. It is best to practice good sleep hygiene. 1. Keep a regular bedtime & wakening time (to include weekends). Get up the same time each day, regardless of what time you fell asleep. 2. Make a regular, relaxing bedtime routine. Relaxing rituals prior to bedtime may include a warm bath or shower, aroma therapy, reading, or listening to gentle music.