A computer model based on the Darcy solution to the Radial Diffusivity Equation was written to evaluate perforated oil well completions. The model was verified using standard well testing techniques and compares favorably with similar models written previously. The results of this study clearly point to these conclusions:

  1. Normal amounts of well and perforation damage reduce four shot per foot (0.305 m) productivity to an unacceptable level. Twelve shots per foot (0.305 m) is recommended for future completions.

  2. Gun phasing affects productivity. Sixty degree phasing gives the best results, with productivity reductions for larger angles.

  3. Perforation length should be maximized at the expense of hole diameter, down to a diameter of 0.25 inches (0.64 cm).

  4. Gun standoff decreases penetration of small diameter, through-tubing guns. These guns should be avoided where possible.

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