Gas Well Performance Analysis with Downhole Gas Compression

Abstract

Downhole gas compression is an artificial lift means that aims to increase production, maximize recovery and delay onset of liquid loading from gas wells. Being a technology not widely implemented yet, its application, benefits, operating window and limitations are not deeply managed by the oil & gas industry community. The compressor boosts gas flow rates by increasing the pressure drawdown in the well proportionally to inlet pressure reduction. The required pressure ratio needs to meet the discharge pressure requirements to overcome well head pressure, column weight and pressure losses across the tubing, but the larger pressure ratio is the higher outlet temperature will be, which may become a limiting factor due to completion, compressor and process specs. Fluid velocity also varies across different casing sections, carrying with changes in liquid volume fraction (LVF) and flow regimes. In general, compressors are known to be low efficient handling liquids, therefore a close investigation on the LVF and flow patterns at inlet conditions must be very well understood for downhole applications. Well modeling and sensitivity analysis will be used in this paper to illustrate in detail the well performance representation with downhole gas application along with a comparative analysis with surface gas compression to evaluate potential gains. Results and observations about these parameters, along with methodologies to calculate inlet/outlet conditions will also be described in this paper, adding to the existing literature a new holistic approach for analyzing gas well performance operated with downhole compressors.