Flow Segmentizers Reduce Erosion of Standalone-Sand-Screen Completion
Authors: Carpenter Chris 
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 25019, ’Reduced Erosion of Standalone-Sand-Screen Completion With Flow Segmentizers,’ by M.S.A. Zamberi and S.N.A. Shaffee, Petronas Group Technical Solutions; M. Jadid, Z. Johar, and I. Ismail, Petronas Carigali; and C.Y. Wong and C.B. Solnordal, CSIRO, prepared for the 2014 Offshore Technology Conference Asia, Kuala Lumpur, 25-28 March. The paper has not been peer reviewed.

Standalone-sand-screen (SAS) completion, especially in horizontal gas wells with high potential for sand production, typically suffers from premature failure caused by sand erosion resulting from high velocity in the annulus near the heel section. This paper describes the work conducted to understand in detail and quantify the erosion risks to SAS completions in horizontal gas wells and to pursue a proof-of-concept assessment of using swelling-elastomer packers to segmentize the flow in the annulus as a means of reducing erosion risks near the heel.

Introduction

During the production phase, decreasing pore pressure will cause a concentration of stresses around the wellbore and perforations, leading to failure of the rock and subsequent transportation of sand particles from the wellbore to the sand-control- equipment interface (e.g., sand screens and gravel pack). In scenarios when downhole sand control is no longer effective, the produced sand will be transported to the surface, leading to other issues such as sand deposition in pipelines and erosion of surface flowlines and equipment.

In gas-dominant systems, as gas is produced from the bottom of the hole to the surface, the volume of gas increases with decreasing pressure, resulting in a significant increase in gas velocity in surface flowlines and equipment, from approximately 1 m/s at the heel section downhole to more than 10 m/s in surface flowlines. Compared with liquid-dominant systems, the relatively low viscosity and density of the gas will cause the sand present in the gas flow to easily escape from the bulk fluid-flow stream and affect surfaces at high velocities, thereby posing significantly higher erosion risks.

It is important to ensure that any downhole sand control applied in gas-dominant systems is reliable, with features that reasonably reduce the risk of premature failure. In the case of SAS completion, most authors and researchers have concluded that screen erosion is by far the most common failure mechanism. It has also been noted that annular flow plays a significant role in the erosion and failure of sand screens in horizontal gas wells.

Despite these technical challenges, application of SASs, as opposed to gravel packs, in horizontal openhole completions has the potential to significantly reduce capital expenditure, expedite well development, and improve productivity (skin). With these factors as the motivation, a proof-of-concept project involving experimental and computational-fluid-dynamics (CFD) models was conducted to assess and develop a methodology to use swellable packers to reduce annular-flow velocity, thus reducing the erosion risk on SAS completions.