This section deals with the subject of whether it is better to convert existing producing wells or to drill new wells for injection purposes. Sometimes it is necessary to drill replacement wells for injection because the old wells are in poor mechanical condition. The old wells are then plugged and abandoned. However, here new wells refer to new locations that are added to complete waterflood patterns. These wells reduce the spacing that existed between the old wells. The decision then must be made as whether to convert old producers to injectors and to drill new producing wells or to keep the existing producers and drill new injectors.

Many operators consider injectors as secondary in importance to producers. After all, injectors produce no oil directly. Therefore, old producers are usually converted to injectors, and any new wells become producers. In fact, usually the worst producers are converted to injectors. These may include the producers with the highest WORs, lowest production rates, and even dry holes. However, it should be considered that poor producers usually make poor injectors.

The decision whether to convert existing wells to injectors or drill new injectors should be based upon economics. The decision should be part of an overall waterflood plan that yields maximum economic oil recovery.

Several other factors should be considered in making a decision concerning conversion of existing wells versus drilling new wells:

1. Bottomhole location

2. Casing size

3. Casing condition

4. Completion technique

A well's bottomhole location is the first factor...