Well Problems

Depending on the well these problems may vary.

For oil:

  • Low Productivity
  • Excessive gas production
  • Excessive water production
  • Sand production

For gas:

  • Low productivity’
  • Excessive water production
  • Liquid loading
  • Sand production

              Low Productivity

The lower than expected productivity based on comparing actual production and production by nodal analysis.

Attributed to

  • Over estimation of reservoir pressure and permeability
  • Formation damage
  • Reservoir heterogeneity
  • Poor completion
  • Wellbore restrictions

              Excessive water production

Usually from water zones not connate water.  Typically fluid density logs are useful for identifying water zones. A spinner flow meter can give an idea where the water is coming from.

              Excessive gas production

May be due to channeling behind the casing through micro annuli in the cement. Can be caused by preferential flow from one formation to one of the gas coning or casing leaks. Production logs can help to determine channeling and coning, typically a temperature log. Density logs can be used to identify the gas zones that existed behind the casing.

              Liquid loading in the gas will

Gas Wells produce liquid water and/or condensate in the form of a mist.  When the gas velocity drops the liquid begins to accumulate in the well bore. This increases the bottom hole pressure and decreases the production rate.

Using smaller tubing sizes can help or the well it can be unloaded by gas lift or by pumping it out. The well ball can be heated all water can be injected. However this problem is not always obvious and recognizing the liquid loading is not easy.

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