Fugitive Emissions Study: How to Minimize and Control Methane Emissions While Utilizing Sand Separators

The goal for all oil and gas well sites is to have zero fugitive emissions. This is functionally difficult during flowback and early production operations, however, minimizing and managing fugitive emissions to net-zero is possible with planning and careful production equipment selection.

Sand separators are a critical piece of flowback and early production equipment. The process of removing sand at high pressure through blowing vessels down to atmospheric pressure, provides conditions where fugitive emissions can be created. In order to reduce the unnecessary fugitive emissions, horizontal or low angle Desanders have shown better performance over vertical or spherical sand separators as they have a larger sand holding capacity as well as a reliable sand measuring system resulting in fewer cleanouts and unnecessary releases of fugitive emissions (Wasfy et al, SPE-196142-MS ¹⁰). Furthermore, simple changes and additions to the rig-up design can be made to allow for all methane emissions to be captured during the process providing options for how to handle greenhouse gases in order to minimize environmental impact.

Using a spherical separator as a base measurement, for 1 m3 (264.2 gallons) of sand stopped a vertical geometry would produce 94.3% of the carbon emissions of the spherical vessel while the horizontal desander would produce 34.5% of the carbon emissions of the spherical and a low angle tilt would produce 14.7% of the carbon emissions. Also, through leveraging improved rig-up design with Horizontal and Low-Angle Tilt Desander, all methane resulting from the desanding process can be captured and directed to flare or vapor recovery reducing the equivalent CO2 released into the environment to near zero.

With the industry moving to achieve the minimal amount of environmental impact, operators are looking at every aspect of the process to reduce methane emissions, including the flowback process. The implementing of horizontal or Low-Angle Tilt Desanders, the sand measurement system, and the improved rig-up design allows for the elimination of open tanks on location during flowback. Further analysis, design improvements, and technology integration continues in order to achieve the goal of eliminating flaring and to conserve all methane produced by compressing into the pipeline and/or reserving to fuel other completions operations.