Overview

Damir Horvat, SPE, Drilling Engineering Manager, Arrow Energy

A key aspect to effective completion design is an accurate understanding of the reservoir and bounding formations. Nearly every well completed in a prolific sandstone formation requires sand control, either as a preventive measure or as remediation later in its production life. Formation damage is another problem associated with wells that produce sand unchecked. The possible creation of void spaces behind the casing can leave the casing and any shaly streaks in the reservoir unsupported. The much less permeable shaly streaks that remain can collapse around the slotted or perforated casing, causing severe and irreparable restrictions to production.

Most authorities recommend that sand-control techniques be applied immediately upon indication that a formation will produce sand. This practice will allow the highest success rate and the lowest production loss possible after sand control is applied. Laboratory studies have shown that once unconsolidated sand is disturbed, the sand cannot be packed back to its original permeability. Therefore, sand control should be applied before the reservoir rock is seriously disturbed by sand production. Also, operators are opting for advanced sand-control completion technologies in demanding gravel-pack and frac-pack completions.

In this environment, the next generation of sand-control completion technologies must be able to handle larger proppant volumes and higher pump rates and place proppant or gravel-pack sand effectively along the sandface completion void free. For most open holes drilled in unconsolidated formations, a gravel pack is the preferred completion option. By filling the annulus between the liner or screen and open hole with specially sized, high-permeability gravel-pack sand, the wellbore is stabilized to control production of formation sand and protect the screen from plugging or erosion. When performed with proper procedures and tools that use the next-generation sand-control completion technologies, gravel-pack and frac-pack completions can be highly productive and long-lasting completions. Finally, the ultimate objective is to create cost-effective technology that builds on proven sand-control technologies and best practices that help operators overcome these serious well-production sand-control challenges successfully.

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Damir Horvat, SPE, is Drilling Engineering Manager, Arrow Energy. He has more than 15 years’ experience in petroleum, geothermal, coal-seam gas, and nonhydrocarbon drilling. Horvat previously worked on joint-venture projects with major drilling and oilfield service companies, state government departments, and government-owned corporations in central and eastern European countries, the Middle East, north Africa, New Zealand, and Australia. He serves as an SPE Queensland Section Director, as a Technical Editor for SPEDC, and on the JPT Editorial Committee. Horvat holds a certificate of completions as Master Driller from School of Mining & Chemical Engineering, Croatia; an Advanced Diploma of Drilling Management and qualified Drilling Industry Assessor by the Australian Drilling Industry Training Committee, Australia; and an ME degree in petroleum engineering from École Supérieure Robert de Sorbon, France.

Overview

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