 For Oil & Natural Gas, one has to carry out Gravity, Magnetic surveys to get rough idea about structure of rock formations.If the desired structure is existing, for detailed study of rock formations, one has to carry out Seismic and/or Magneto-telluric surveys.The gravitational pull of the Moon and Sun give rise to two high tides and two low tides every lunar day, or every 24 hours and 50 minutes.