Sanding: An Expert-System Approach for Assessment and Control in Wells

Abstract

The sand production problem is plaguing the petroleum industry by its adverse effects on thousands of oil and gas fields throughout the world. A tremendous amount of money is spent each year on attempts to predict and control sand influx and/or repair wells and equipment damaged by sand. Sand inflow into the well during production leads to casing abrasion and failure, formation damage and distortion, and frequent sand removal and cleaning. The sand control process has a major influence on the type of the well completion design and it influences the guidelines for the completion process. In addition, many wells are currently being produced below their potential in order to restrict sand influx or erosion, and/or as a result of poorly designed or installed sand control methods. Evidently, the sand prediction and control problem is exceedingly complex and suggests the use of heuristics and the appropriateness of the expert systems technology. An automated sand control consultant and expert system has been developed. The system is aimed at assisting users in predicting sand occurrence during production and in selecting and designing the proper sand-exclusion treatments. The knowledge base of the system is based on an easy upgrade, easy expand format and involves four primary modules, thus giving the end-user greater flexibility to tentatively access and evaluate different scenarios of knowledge processing. Input data can range from “not known” formation characteristics and/or well stimulation requirements, for which the system gives conservative recommendations based on the remaining known facts, completion characteristics of the hole, well history, and geological probability; to cases with detailed information available, in which case very elaborate and precise recommendations are prescribed. This paper describes the knowledge involved in various modules of the sanding system, as well as future plans and further developments.