Abstract

Expandable sand screens were developed to overcome the shortcomings of both existing sand control techniques, while also providing some unique benefits. The first commercial application of this technology took place in January 1999. Since then, their use has spread quickly to all parts of the world and in many diverse applications. As of June 2005, over 340 installation of expandable sand screen (ESS) had been run in over 700 years of combined production.

The productivity performance of the ESS has been shown to be very good, with an average skin of 0.3 being achieved in recent openhole applications. ESS completions generally perform better than the baseline models. Where field comparisons were possible, they also performed better than alternative sand control completions.

However, its introduction and acceptance into the Iran has been slower in coming. It was not until in 2005 that National Iranian Oil Company (NIOC) decided to complete its Mansuri oilfield, well MI-34 sidetrack, using openhole expandable sand screen for sand control, thus making it the first such completion in the Iranian oilfields. This paper will provide a brief overview of expandable sand screen, its construction and advantages and will describe some of the issues addressed in this well completion. It will provide details of the installation procedure, the fluids employed and well production results achieved. It will conclude that the use of expandable sand screen as an alternative to conventional sand control methods in the Iranian Oilfields is viable.

Introduction

Mansouri 34 is the first application of openhole ESS (Expandable Sand Screen) technology within Southern Iran. NIOC awarded the contract of sand control solution as a part of Mansuri oilfield development project to Weatherford Completion and Production Systems. There were some wells completed with ESS in southern Iran before but they all were cased hole, hence make this job the first time of its own. The deployment and expansion of the screens was carried out as per the Weatherford guidelines without any problems. An openhole completion strategy was selected in order to boost well productivity, with the reservoir section lined with ESS in order to provide borehole support and optimize production rates still further and more importantly allow them to be sustained for a longer period, improving ultimate reservoir recovery factors.

The operation began with the setting of a whip stock. A window was then milled in the 7" liner. The kick off point was at 2153.5m. A total length of 64m of 6–1/8" openhole was drilled. This produced a 52m reservoir section between 2168m and 2220m.

The formation was then acidized to remove the mud cake. Following the acidization, the casing was scraped. This ensured the deployment packer had no problems setting, and there was nothing in the well that might damage the ESS. The EXP hanger-packer was set in the 7" 29 lb/ft liner with the expandable sand screens across the Asmari Formation.

The ESS was then expanded using the Axial Compliant Expander Tool (A.C.E. tool). The back pressure generated by pumping through a bit nozzle in the tool nose ensures the sand screens are expanded to fully contact the borehole, even in irregular hole geometries.

Background

Well History- The well was drilled in 1993 in the axial structure of Mansuri field and in 800 meters NW of well MI-15 and 1300 meters SW of well MI-6. The formations were drilled without a major problem from Aghajari formation in surface to 2294 m TD in Asmari formation. The cap rock is determined at 2164 m, drilling through Asmari formation was reported with slight losses. The well was producing from sandstone layer 3 of Asmari formation.

Objective of Sidetrack and Re-Completion- The objective of sidetrack and re-completion in this well was to increase production from layers 1 & 2 of Sandstone Asmari formation as well as cut the sand production with installing a sand control device in the well. NIOC decided to use expandable sand screen (ESS) as the most profitable sand control method over existing sand control solutions for this well.

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