Chokes in Series Provide Safe Testing Operations in Wells with Abrasive Solids

Abstract

Solids production has been an issue in the oil and gas industry for years. Several materials and configurations have been tested under different conditions to determine how to produce fluids more efficiently when abrasive solids are present. This paper discusses well-testing operations involving formations with the potential for solids production. The discussion focuses on the choke manifold, which is a crucial piece of equipment used during testing operations. The choke manifold facilitates dual-flow paths that control the well flow at surface from the upstream control equipment to the downstream process equipment and allows the operator to perform choke changes without interference to operations or test objectives. It is responsible for controlling the flow rate, upstream choke pressure, downstream choke pressure, and for maintaining critical flow. These tasks are easily achieved using a single choke when no solids are produced. However, when solids are present during the flow through the choke manifold, erosion can occur in the choke body and beans. When these parts are damaged, the well should be shut-in and all operations suspended to repair the damaged equipment. Previous experience shows that the use of chokes in series combined with a high-resistance material (tungsten carbide) improved the choke manifold capacity to work with abrasive solids with less erosion issues. Such capability relies on the lower velocity and pressure changes provided by chokes in series. The choke configuration was tested in the field with a high abrasive flow (gas with solids) and resisted, as expected. Computational fluid dynamics (CFD) simulations were used to analyze the flow-velocity profiles in the flow path of the choke manifold. This study presents a comparison of these results with actual field data (pressure upstream and downstream of the choke manifold during different flows) to demonstrate how the three-choke system can provide safer operations with abrasive flows.