sand Production Prediction

Sand Production Prediction

W.R. Moore, SPE. BJ Services Co.

Many investigators over the years have researched the causes of

sand production and searched for a reliable means to predict it. Sand

production prediction is important because of the safety,

environmental, and operational concerns involved when produced

sand particles fill and plug the wellbore, erode downhole and

surface equipment, and increase operating expense. Currently, no

method of sand production prediction is universally regarded as

accurate and reliable within the industry.

A number of prediction models have been developed to identify

completions that may be expected to produce sand. Earlier attempts

to develop prediction techniques included statistical models,

numerical models, mechanical properties logs, sand strength logs,

and core studies. Often the individual attempts to develop a predictive

model were specific to the type and locale of the reservoir being

studied; i.e., water production, pore pressure depletion, perforation

geometry, pressure drawdown caused by skin effects, and a variety

of other critical parameters were not always considered.

The dilemma of an independent U.S. operator faced with a

completion decision regarding sand control is not that different

from the problems considered by large North Sea production

companies. Quite often, the most cost-effective method to

determine the need for sand control is by analogy from data

collected from offset wells. Complex 3D numerical modeling in

concert with extensive laboratory analysis of core and log data is

not always economically practical but is the most technically

correct method with an acceptable degree of accuracy when

properly performed. l

TABLE 1-DATA CONSIDERED IN A COMPLETE

EVALUATION FOR PREDICTING SAND

PRODUCTION POTENTIAL

1 . Field data.

2. Cyclic loading.

3. Directional in-situ stresses.

4. Quality of cementation.

5. Perforation geometry and spacing.

6. Perforation cavities geometry and shot density.

7. Cavity evolution effect of varying perforation

geometry.

8. Well pressure.

9. Flow rate (fluid forces).

10. Permeability, viscosity, and relative permeability

for two- and three-phase flow.

11. Rock deformation characteristics.

12. Rock strength characteristics.

13. Flow through porous media where nondarcy flow is

included.

14. Log-derived rock mechanical properties.

15. Laboratory tri-axial measurements of core

samples.

16. Regional tectonic forces.

JVf • November 1994

Historically, much attention has been given to sand production

prediction. The vast differences and complexities observed

between the models and techniques that have been developed

suggests