Locating, Quantifying, and Remediating Downhole Sand Infiltration to Minimize Equipment Failures and Increase Oil Production: A Case Study in Kuwait

Abstract

Sand infiltration requires immediate action to avoid costly downhole and surface equipment erosion. Additionally, sand particles may reduce hydrocarbon production by blocking downhole fluid flow. This study demonstrates the advantage of integrating multiple reservoir monitoring logs to identify the sand contribution zones, quantify the sand production, and plan the well remediation work required, while minimizing operation downtime.

A focused logging program and analysis method was developed to identify the sand infiltration location. Integration of passive acoustic and array-based production logs acquired the critical data to find the sand infiltration zones. The passive acoustic tool captured the count of inflowing sand strikes on the tool body generating a definitive acoustic signature. The array production logging tools mapped the fluid rates, flow delays, and fluid transport in the well. Post-processing of the passive acoustic data counted the unique sand strike events resulting in a quantitative sand infiltration assessment for a high deviation well penetrating Burgan and Wara reservoirs.

Sand and hydrocarbon production occurred in the Burgan reservoir, while the Wara formation was initially not producing any type of fluids due to Burgan sand infiltration. Within the Burgan formation large quantities of sand were detected inside the wellbore and approximately 100 feet below the inflow location. While some sand particles circulate up-hole with the flow others settle on the bottom. Acoustic logging analysis indicated that sand infiltration was generated from the middle Burgan perforations between 5737 ft and 5742 ft. According to the production logging analysis, less than 250 STB/D Burgan oil production was only flowing from the upper-most perforations between 5714 ft and 5718 ft due to sand fill below. Remediation action focused on a cement squeeze in the middle Burgan to close the sand infiltration perforations then a subsequent re-perforation of the Wara formation to resume production in that section. The Wara formation was relogged after perforation confirming reduced sand infiltration and an oil gain of 1530 STB/D with 170 STB/D of water production. Therefore, the sand infiltration information resulted in improved remediation outcomes. The integrated measurements clearly established the impact of sand infiltration on fluid inflow and created a road map for future well monitoring improvements.

This case study illustrates the successful integration of passive acoustic and array-based production logging to detect the sand infiltration zones and the high value fluid inflow zones. Well remediation activities were further optimized, re-establishing oil flow of 1530 STB/D from a set of non-producing perforations of the Wara formation.