ABSTRACT
The Hugoton Field in southwestern Kansas, western Oklahoma and northwestern Texas is the largest gas field in North America. Gas production is from the shallow (2,100+ feet to 2,900+ feet) heterogeneous, multi-layered Chase reservoir. This paper details the results to date of an individual layer pressure testing program conducted by Mobil in 1992 on two wells in the Kansas Hugoton field. The recent history of pressure transient attempts in the Hugoton field is covered. How this information was used in planning the testing programs, foam drilling and coring, drill stem tests (DST), wireline pressure testing, in-situ stress and strain testing, and logging programs is explained as well as the evolution of the drilling, individual layer DST, completion, and individual layer cased hole testing operations and procedures. These wells represent the first time in recent history individual layer pressure and rate data has been measured in non-stimulated layers on any wells in the Hugoton field. The results of this test program are covered as well as how this data is being incorporated into Mobil's reservoir characterization and simulation efforts in this field. This analysis shows: (1) The pressures ranged from 142 psia to 320 psia, compared to 484 psia initial bottomhole pressure, in the five major carbonate layers in the Chase reservoir, (2) The three more permeable layers had the lowest pressure and were being effectively and efficiently drained while the less permeable layers had the highest pressure and were being effectively, and possibly efficiently drained, by original wells 2,100 feet to 3,300 feet away, (3) The wireline pressure testing results were accurate and precise, but often not representative of the layer pressures in the individual layers, and (4) The various testing operations require extra planning in a foam system due to underbalance conditions and conflicting wellbore fluid requirements.
