Facilities Sand-Management Techniques Fall Into Two Types: Inclusionary and Exclusionary
Authors: Wilson Adam 
Published: February 2015

This article, written by Editorial Manager Adam Wilson, contains highlights of paper SPE 164645, ’Sand-Management Methodologies for Sustained Facilities Operations,’ by C. Hank Rawlins, SPE, eProcess Technologies, prepared for the 2013 SPE North Africa Technical Conference and Exhibition, Cairo, 15-17 April. The paper has not been peer reviewed.

Traditionally, sand-control equipment is used to prevent sand from entering the wellbore. This technique can be termed “exclusionary.” An alternative is to produce solids with the well fluids and separate them at the surface. This technique is termed “inclusionary” because the solids freely flow with the fluids to the surface. Exclusionary techniques protect production tubulars, wellhead chokes, flowlines, and facilities equipment. However, the buildup of solids near the wellbore increases skin damage, which reduces inflow. Allowing the sand to flow freely with the well fluids reduces skin damage, thus sustaining or increasing inflow.

Introduction

Several production companies have started to integrate facilities sand management into their sand-control portfolio. Equal merit is given to sand separation at the surface facilities and to completion technologies, to determine which approach provides sustained hydrocarbon production. Gravel-pack and screen completions have a well-established installation and operating base and form the majority of conventional sand control. While controlling sand production in numerous wells, these techniques may still pass sand with diameter of &lt;50–125 µm under normal operating conditions, and this sand interferes with facilities operations. In the case of a completion failure, the sand amount and particle size may increase rapidly, leading to production restrictions or damaged equipment.

The necessity for a technology that could protect surface-facilities equipment (e.g., chokes, flowlines, pumps, separators, and valves) in cases of completion failure, openhole completion, or rapid unplanned sand production led to the development of the multiphase desander for solids removal at the wellhead.

Sources, Characteristics, and Problems of Produced Solids

In comparing exclusion approaches (i.e., completions or production limits) vs. surface separation methodologies for produced solids, it is necessary to clarify the exact nature of the solids being treated. Produced solids are inorganic, insoluble, nondeformable particulate materials accompanying hydrocarbon-fluids production. These solids are produced from oil, natural-gas, water, or multiphase wells.

Inorganic particulates that are produced at sufficient size and concentration to require exclusion or separation treatment are generally termed “produced solids.” This material can be broadly classified into two categories: indigenous (natural) material and foreign (artificial) material.

Natural Solids. Natural solids arise from the indigenous reservoir minerals. Broadly, these are sands, which are detrital grains of mineral oxides (e.g., SiO2), and clays, which are hydrous aluminum silicates that may be detrital or authigenic. Sand particles are the load-bearing solids of the formation, while fines (clay) are not part of the mechanical structure.