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Degradation of Polyester Diverting Agents with Sodium Hydroxide

IP.com Disclosure Number: IPCOM000245885D
Publication Date: 2016-Apr-15
Document File: 9 page(s) / 421K

Publishing Venue

The IP.com Prior Art Database

Abstract

This paper presents laboratory results documenting the effect of sodium hydroxide on polyester stimulation diverting agents. This body of work applies in general to stimulation when using these types of diverting agents. Well Stimulation, acidizing or hydraulically proppant fractured, success and the resulting Oil and Gas production is dependent on multiple variables for both new well stimulations and refracturing already producing wells. Key variables are the number of fractured stages and the number of perforation clusters effectively stimulated per stage. Fluid placement into multiple perforation clusters is critically important to avoid inefficiencies in production from a low percentage of stimulated clusters contributing to production (i.e. 50% of the clusters contributing to 90% of the production).

Fracturing fluid diverting agents have been used successfully to maximize reservoir contact and better optimize proppant distribution which leads to improved long-term production performance. An effective diversion additive should be specifically designed with a known particle size or range, degradable, and rigid when placed.

Reservoirs with low bottom hole temperatures of 40 oC or less pose a unique challenge for the removal of a diverting agent. A new approach to diverting removal has been developed and studied in the laboratory.

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Page 01 of 9

      Degradation of Polyester Diverting Agents with Sodium Hydroxide Abstract

This paper presents laboratory results documenting the effect of sodium hydroxide on polyester stimulation diverting agents. This body of work applies in general to stimulation when using these types of diverting agents. Well Stimulation, acidizing or hydraulically proppant fractured, success and the resulting Oil and Gas production is dependent on multiple variables for both new well stimulations and refracturing already producing wells. Key variables are the number of fractured stages and the number of perforation clusters effectively stimulated per stage. Fluid placement into multiple perforation clusters is critically important to avoid inefficiencies in production from a low percentage of stimulated clusters contributing to production (i.e. 50% of the clusters contributing to 90% of the production).

Fracturing fluid diverting agents have been used successfully to maximize reservoir contact and better optimize proppant distribution which leads to improved long-term production performance. An effective diversion additive should be specifically designed with a known particle size or range, degradable, and rigid when placed.

Reservoirs with low bottom hole temperatures of 40 oC or less pose a unique challenge for the removal of a diverting agent. A new approach to diverting removal has been developed and studied in the laboratory.

Introduction

Fracturing design simulations can be used to optimize treatments based on formation attributes. The primary factors that affect fracture design (Hards et al. 2013) include the following:


• Pay thickness

• Stress profile

• Pore pressure

• Water saturation

Secondary factors affecting fracture design include the following:


• Depth

• Permeability/porosity

• Young's modulus/Poisson's ratio profile
• Lamination

• Brittleness


Page 02 of 9

These geological parameters of the formation and rock properties vary widely, which leads to differing fracturing treatment designs with respect to the following:


• Number of fracturing stages
• Tonnes of proppant

• Proppant type

• Proppant schedule

• Pumping rate

• Fluid type

Effective execution of the designed fracturing treatment in open hole horizontal completions (sliding sleeve, plug and perf or multiple perforation clusters in a cemented completion), or in a horizontal refracturing operation present challenges when trying to obtain an even fracture and proppant distribution amongst all the perforation clusters in a given fracturing stage. The lower-stress clusters will take the majority of the stimulation energy initially, and once a fracture is initiated in a lower stress interval it can be difficult to break down the higher-stress clusters. The use of a diversion agent can seal off the lower-stress clusters or previously fractures zone and divert the fracturing treatment to other perforation clusters to achieve a higher density of fractures. Higher dens...