Abstract

This paper discusses hydraulic fracturing treatments for unconsolidated sand reservoirs. The procedures needed for selecting the appropriate candidate wells, designing successful treatments, executing them and evaluating the results, are presented in a format directly usable by the practicing engineer. presented in a format directly usable by the practicing engineer. Field examples illustrate some of the key techniques.

Introduction

Several successful hydraulic fracturing treatments have recently been performed in different Gulf of Mexico reservoirs, and resulted in improved production following gravel-pack completions. Many Gulf Coast reservoirs are good candidates for hydraulic fracturing, despite the common thinking that fracturing treatments are only for low-permeability, hard-rock formations. The high-permeability, unconsolidated sands typical of the Gulf Coast, pose different challenges than the hard-rock reservoirs where most of the hydraulic fracturing experience has developed. Lower proppant concentrations may be considered adequate for hard-rock formations, however, as much as 4 lb/sq ft or more may be required for soft formations. The tip screenout technique is essential to achieve these higher sand concentrations. It ensures that the fracture width and proppant concentrations are adequate to efficiently connect the proppant concentrations are adequate to efficiently connect the reservoir to the wellbore. This paper presents a comprehensive analysis integrating the candidate well selection, the design, the execution, and the evaluation of hydraulic fracturing of soft formations. It draws on recent experience in fracturing offshore unconsolidated sands, and presents some of the current techniques employed in a format directly usable by the practicing engineer.

PREDESIGN EVALUATION PREDESIGN EVALUATION

The candidate wells selection based on well performance and the identification of an appropriate fracture placement model, are two essential steps that ensure the success of the treatment. These steps should be systematically applied prior to the fracture placement design. placement design.

Candidate Well Selection

A quick review of readily available well and reservoir data permits the identification of candidate wells that would benefit permits the identification of candidate wells that would benefit from a hydraulic fracture stimulation treatment.

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