Estimating well downtime factor in field modeling

1. A method comprising: obtaining, using a production tree coupled to a computer system having a computer processor, reservoir data and a plurality of downtime factors for a well extending from a surface location to a reservoir and capped at the surface location by the production tree; determining, using the computer processor, an absolute potential flow rate for the well using the reservoir data, wherein the absolute potential flow rate corresponds to an amount of hydrocarbons the well could produce without well constraints; uniformly reducing, using the computer processor, an initial productivity index of the well from the absolute potential flow rate to an abandon well flow rate to create a plurality of reduced productivity indexes comprising a plurality of productivity index multipliers, wherein the initial productivity index is a measurement of an ability of the well to produce hydrocarbons at a predetermined rate; determining a plurality of downtime factor percentages for the well, wherein each downtime factor percentage among the plurality of downtime factor percentages represents a ratio of a variable well production rate at different downtime factors to the absolute potential flow rate; determining, using the computer processor, a relationship between the plurality of productivity index multipliers and the plurality of downtime factor percentages for the well, wherein the relationship represents a plurality of potential production losses for the well; predicting, by the computer processor and using the relationship, production losses of a field of wells as a result of the plurality of downtime factors; determining, by the computer processor, an optimum downtime factor for the well using the relationship between the plurality of productivity index multipliers and the plurality of downtime factor percentages; transmitting, using a command console, the optimum downtime factor to the computer system coupled to the well; and performing, using the production tree and the computer system communicably coupled to the well, a shut-in well maintenance of the well based on the optimum downtime factor.

2. The method of claim 1 , wherein uniformly reducing, by the computer processor, the initial productivity index for the well further comprises running several reduction simulations of the initial productivity index.

3. The method of claim 2 , wherein the relationship between the plurality of productivity index multipliers and the plurality of downtime factor percentages for the well represents the plurality of potential production losses.

4. The method of claim 3 , wherein the plurality of downtime factors are one or more factors selected from a list comprising: shut-in well maintenance, well surveillance, and operational performance.

5. The method of claim 1 , further comprising: determining production rate over time for a field, having a plurality of wells, using the optimum downtime factor for each well.

6. The method of claim 1 , wherein the relationship between the plurality of productivity index multipliers and the plurality of downtime factor percentages for the well depends on a dynamic simulation model.

7. The method of claim 6 , wherein the relationship between the plurality of productivity index multipliers and the plurality of downtime factor percentages for the well is a non-linear relationship.

8. The method of claim 7 , wherein the relationship between the plurality of productivity index multipliers and the plurality of downtime factor percentages for the well is an exponential relationship.

9. The method of claim 1 , wherein the initial productivity index is equal to the absolute potential flow rate for the well.