Determining The Best Methodology to Commence Production from a Tight Gas Reservoir in its late life; A Case Study

Lots of wet and condensate gas reservoirs, in their late life will encounter problems such as low gas flow rate, liquid loading and dead wells. These issues are even more severe when the well conductivity is low and most of the reservoir energy is consumed in order to push fluids into wellbore. Low gas flow rates mean low gas velocity and this is the cause of liquid loading phenomena that will result in killing the well if it last enough and not treated with unloading methods. A gas field in its 2nd half of production was selected to implement the study of determining the best scenario to commence feasible production from field.All of the wells of this gas field was simulated using a well flow simulator and three scenarios were applied in the software in order to see their effects on well behavior. Lowering the surface pressure, changing the tubing size and length and stimulating the well in order to reach higher well conductivity were introduced into software. The results were plotted during future life of the reservoir.Results showed that the best scenario in order to maintain the field production at a desired value is to lower surface pressure either by installing surface compression stations or lowering the inlet pressure of the gas refinery. Changing completion string size or length didn’t provide us much benefit, as we will see for this case, changing completion string to a lower diameter will just help to produce for a small period (months). And for this special case, Although the current field problem is liquid loading, unloading methods that result in reducing well column pressure loss will not help the field production effectively.

کلیدواژه ها:

Gas field ، Liquid Loading ، Low Conductivity Reservoirs ، Gas Field Management