Oil and Gas

Biography

Biography: Abdollah Esmaeili

Abstract

In formations where the sand is porous, permeable and well cemented together, large volumes of hydrocarbons which can flow easily through the sand and into production wells are produced through perforations into the well. These produced fluids may carry entrained there in sand, particularly when the subsurface formation is an unconsolidated formation. Produced sand is undesirable for many reasons. When it reaches the surface, sand can damage equipment such as valves, pipelines, pumps and separators and must be removed from the produced fluids at the surface. Further, the produced sand may partially or completely clog the well, substantially lead to poor performance in wells and, ultimately, inhibiting production, thereby making necessary an expensive work-over. In addition, the sand flowing from the subsurface formation may leave therein a cavity which may result in caving of the formation and collapse of the casing. Sand production in oil and gas wells can occur if fluid flow exceeds a certain threshold governed by factors such as consistency of the reservoir rock, stress state and the type of completion used around the well. The amount of solids can be less than a few grams per cubic meter of reservoir fluid, posing only minor problems, or a substantial amount over a short period of time, resulting in erosion and in some cases filling and blocking of the wellbore. Although major improvements have been achieved in the past decade, sanding tools are still unable to predict the sand mass and the rate of sanding for all field problems in a reliable form. This paper provides a review of selected approaches and methods that have been developed for sanding prediction. Most of these methods are based on the continuum assumption, while a few have recently been developed based on discrete element model. Some methods are only capable of assessing the conditions that lead to the onset of sanding, while others are capable of making volumetric predictions. Some methods use analytical formulae, particularly those for estimating the onset of sanding while others use numerical methods, particularly in calculating sanding rate.