Secondary Natural Gas Recovery: Targeted Technology Applications for Infield Reserve Growth: Case Studies Evaluating the Benefits of Secondary Gas Recovery, Onshore Gulf Coast, South Texas

Abstract

Economic recovery of natural gas in reservoirs with near-tight to conventional porosity and permeability can be improved through geologically based infill-development strategies. Old gas fields may contain new infield reservoirs, incompletely drained reservoir compartments, untapped reservoir compartments, and bypassed reservoirs. These secondary resources may be identified by a combination of log evaluation and production and pressure analyses, and they are controlled by structural and stratigraphic heterogeneity. Many gas fields in the Gulf Coast may contain opportunities for identifying additional gas resources at modest costs. Remaining natural gas in these fields can be contacted either by recompleting existing wells that have bypassed reservoir compartments or by drilling strategically targeted infield wells. Exploration for new, untapped, or incompletely drained reservoir compartments or bypassed gas zones in old fields can be improved by using state-of-the-art formation evaluation tools and engineering, production, petrophysical, and geological analyses. The economics of developing and producing the secondary gas recovery (SGR) resource is evaluated for two producing properties in existing fields. The case I study area (North Mcfaddin field) had total operational and development costs (excluding royalties) of $0.58 per mcf, compared to total costs in case II (Agua Dulce field) of$0.83 per mcf. Future application of SGR concepts and technology to strategically targeted well locations and recompletions could further lower development costs.Bureau of Economic Geolog