Comprehensive Diagnostic and Water Shut-off in Open and Cased Hole Carbonate Horizontal Wells

Abstract

Increases in water production can significantly reduce well performance and life of a well, and cause decreased oil production. Water influx can occur through several mechanisms and approach from several directions; accurate diagnostic information is important for the design of successful shutoffs and effective results. To mitigate this situation, water management is crucial. One option is to isolate the water producing zone with a rigless water shut-off technique, which is less costly than the use of workover rigs for interventions. This paper presents case histories of five horizontal wells drilled in carbonate formations and producing excess water; three were completed in open hole and two were cased. A multiphase production logging (MPL) tool equipped with five miniaturized spinners for phase velocity measurement and six electrical and six optical probes for holdup data provided important diagnostic data for the decisions on remedial actions. Using the tool data, the operator pinpointed the water entries and performed shutoff operations based on the source of the entries and water flow profiles. Subsequent production test results showed that the water cut was reduced in all the wells. Examples from open and cased hole completions are shown utilizing a number of different shutoff techniques. In addition, oil production was considerably increased in many of the wells. These results demonstrate that accurate diagnostic information and an integrated approach are keys to successful rigless water shutoffs.