The present exploitation conditions of the Ahuachapan field are discussed. The high well density in a small area has resulted in a significant reservoir pressure decrease due to the inherent reservoir over - exploitation. The average pressure in the exploit at i o n zone has decreased from the 1975 value of 34 kg/cm2 to the May 1983 value of 23 kg/cm2. The production decline characteristics of the Ahuachapan wells were examined, concluding that a l l wells but Ah-22 show exponential decline. The cumulative production - reinjection for the field up to April 1983 is 159.090 x lo6 tons, and 37.592 x lo6 tons, respectively. of reinjection upon field behavior is evident when observing the pressure decline characteristics of the field. It is seen that for in j e c - t i o n fraction related to total mass extracted above 30 percent, the average decline pressure in the production area becomes approximately stabilized. If this condition is not met the r e servoir pressure decreases sharply. From this finding it is concluded that a careful and properly planned r e injection program is a must for the field. The observed temperature reduction in some of the wells seems to be the result of two operating mechanisms. First, we have the pressure decline that produces water vaporization and the consequent temperature descend. Analys is of information available shows no clear indication of deleterious temperature effects on the producing wells due to injection. The only exception Gyjerved to date is well Ah-5 that because i t s close distance and its rel-ative structural position and direct hydraulic connection to injector Ah-29, presented condit ions for fast displacement of the thermal front, resulting in u n sufficient contact area and residence time for reheating of the injected water.

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