ABSTRACT
The Hugoton Gas Field is the largest gas field in the lower 48 states and represents a significant portion of the domestic gas production and reserve base in North America. The gas bearing Chase Group is characterized as a heterogeneous, multi-layered, no-crossflow system with over 5,925 producing wells in Kansas alone.
This paper reports the results of a three dimensional (3-D) reservoir simulation model that predicts the behavior of this multi-layered system under various producing scenarios. The 28 well pattern model covers a 25 square mile representative portion of the field called the "Nix area". The area was initially simulated in 1985 to primarily study the potential benefits of infill drilling. This earlier work is the fundamental blueprint from which today's current model is built. It was felt that by incorporating aspects of the previous study into the current model, it would provide a unique baseline to compare and contrast the earlier predictions against new data and our increased understanding of the Hugoton field, some seven years and approximately 1,660 infill wells later. The current model also contains two new replacement wells and an observation well that have been drilled since 1985. In addition, individual layer pressure data has been gathered along with the additional 10 years of production and pressure data which has occurred since the first study. Using the new model, various prediction runs were made to project each well's future deliverability, ultimate recovery and determine each individual layer's abandonment pressure, with or without infill drilling.
Results from the study indicate that the remaining life of the Kansas portion of the Hugoton field to be at least 40 to 50 years under existing producing conditions. The major gas producing layers will abandon at average bottomhole reservoir pressures ranging from 30-40 psia, while the tighter, less productive layers abandoning between 140–210 psia, regardless of infill drilling or. not. This will result in an expected ultimate recovery of between 90%–92% of the initial gas-in-place for the major producing layers, and between 58%–68% ultimate recovery in the tightest layers. The study also indicates that due to the laterally continuous nature of the geologic layers, infill drilling will result in only a period of reserve acceleration, with no significant, incremental reserves being developed.
