Mechanical methods of sand control involve use of gravel to hold formation sand in place ( with a screen to retain the gravel), or a screen to retain the formation sand ( with no gravel).
The basic problem is how to control formation sand without an excessive reduction in well production.
Basic design parameters include:
1. Optimum gravel size in relation to formation sand size.
2. Optimum screen slot width to retain the gravel, or if no gravel, the formation sand.
3. An effective placement technique-perhaps most inportant.
The keys to successful gravel packing are:
1. Selecting gravel of the proper size and quality.
2. Placing the gravel without contamination, at the proper location, as tightly as possible then holding it in place for the life of the well.
The crux of the problem is to control the loadbearing solids without excessive loss of productivity. Where reservoir conditions are such that high production rates can be sustained, every trick must be employed to maximize productivity and reduce flow velocity per unit area ( reduce drag force).
Quality control important suitability of a particular gravel depends on:
2. Grain strength
3. Acid solubility