Sliding hernia or spigelian hernia, which one has a higher chance of causing intestinal obstruction?

Depends. Depends on the size of the defect in the abdominal wall, and whether or not there is intestine that is included in the herniated contents. Both types of hernia can and have in the past caused intestinal obstruction. Odds are in your favor that it will not cause an obstruction. That does not predict the future however. See a general surgeon for consultation to find out more.