New Opportunities for Time-Sensitive Gulf of Mexico Completions
Authors: Womble Allen W. , Van Sickle Ed , Mckown Mike 
Published: October 2008

Single-trip multi-zone (STMZ) sand control completion systems are not new to the Gulf of Mexico, but the adaptation of these systems for frac-packing has created new opportunities for this technology for time-sensitive completions. Frac Packing involves relatively large amount of complex fluids, chemicals and proppants, also deployment depends on capital intensive equipment. These factors create a quite time-sensitive operation; time becomes a significant variable in project economics. The STMZ systems were first proven in offshore California in the 1980s. In 1990, after success in California completing several hundred wells, the STMZ technology was brought to the Gulf of Mexico. Two key drivers provided the initial opportunity for Gulf of Mexico applications (1) to minimize rig time and (2) to reduce formation damage in the Gulf of Mexico by reducing formation exposure time to completion fluids. System modifications were required for Gulf of Mexico application. With the introduction of frac-packing in unconsolidated formations of the Gulf of Mexico, the technology was again modified to address the higher operating pressures, rates and proppant volumes required for frac-packing multiple zones in a single trip. A premium is placed on saving trips, if measured depth of reservoir targets increases. To date, there have been ten runs of the current system in the Gulf of Mexico, nine of which were executed without nonconformance. The STMZ system now working in the fracpacking environment provides additional cost and time savings such as optimum stimulation vessel utilization and optional electric line perforating, each of which were not previously captured.

This paper will briefly review the history of STMZ systems and discuss how the systems were adapted to facilitate frac-packing, including modifications for high pump rates, pressures and large proppant volumes. The paper will also present detailed results of the recent applications in the Gulf of Mexico that demonstrate the advantages of the technology over more onventional stack-frac pack completion methods.

Introduction

Single-trip multi-zone frac-packing provides flexibility and time-saving advantages that enable well-specific solutions with substantial savings as compared with conventional stacked fracpacking operations.

Single-trip, multiple-zone gravel pack systems are not new to the Gulf of Mexico, but the adaptation to frac packing has created new opportunities for this technology. Single-trip, multi-zone (STMZ) gravel pack completions where first proven in the early 1980â??s in the Beta field, offshore California. The productive interval was composed of as many as nine separate zones with a gross interval thickness of 1200 feet. The system provided zone isolation in the form of packers without the normal packer slips, and hence the first zone isolation packers were created. The gravel pack liner assembly consisted of a series of screen / isolation packer / gravel pack port combinations, one combination per zone. Seal bores were positioned above each isolation packer and below the gravel pack port to be used for positioning of a gravel pack seal