Case Study: Sand Management Evolution in a Brownfield

摘要

A Brown field has been in production for over 30 years. A redevelopment plan started in 2004 to revamp oil production under an Alliance partnership between an Oil & Gas Company Malaysia and Schlumberger. The mentioned Brown field is a multilayered reservoir where the UCS can vary from 1500 psi in the consolidated sand until less than 800 psi in the shallow zones. Based on a geomechics study and existing production history of the field,unconsolidated producer sands were identified and sand control methods were evaluated according to the degree of achieving the goals, and reducing risk, the result indicates that the Cased Hole Gravel Pack with Alternate Path System was preferential. Additional information was obtained in the latest campaign during the retrieval of gravel pack screens in 2 sand producing wells, which gave a better understanding of the failure mechanism in the previous gravel pack operations. The main changes in the design of sand control systems during 8 years includes adopting a perforating strategy of performing a mechanical backsurge, increasing shot density and charges with low debris, use of a 3-way sub tailpipe system to avoid problems associated with breaking flapper valves and debris accumulation, number of cup packers, size of screens, slurry concentration and back pressure applied during the treatment. Furthermore the evolution in the sand control management have showed benefits such as increasing the number of gravel pack zones per well, performing longer gravel packs, installing permanent downhole gauges and using bigger tubing. This paper presents as case study of the evolution and the impact of the sand management systems, showing the significant changes in the design and execution of gravel packs and describing the reasons for those changes. The impact is analyzed on the basis of formation damage, GP factor, execution, risks and results of the initial production.