- OGA publication

Central North Sea HPHT Pressure Cell Study

HPHT (high pressure, high temperature) fields in the Central North Sea (CNS) account for a significant portion of UK total production. Expediting the successful exploitation of new HPHT structures in the UKCS can play a major role in maximising economic recovery and extending the asset life of existing infrastructure. While HPHT conditions are recorded in a number of UKCS basins, by far the largest resource attributable to HPHT producing fields, discoveries, and mature prospects lies within the Central Graben of the CNS. 

This pressure cell study focusses on the Jurassic and Triassic stratigraphic intervals in the CNS. The objectives of this study are to provide a regional understanding of overpressure distributions or pressure cells in the Central North Sea together with a supporting QC’d well pressure database. This will: 

  • support improved mapping of overpressure distributions for prospective plays,
  • develop an understanding of the subsurface pressure regimes onto which the HPHT portfolio of leads and prospects can be mapped and distinguished from the NPNT (normal pressures and temperatures) portfolio,
  • provide a publicly released dataset on which further research and analysis can be based, through universities, industry collaboration, etc. without the barrier of high data costs and complex data licensing arrangements,
  • help identify gaps in the data that is currently available.
  • stimulate exploration activity around key producing infrastructure in a timely manner
  • support more accurate models for top seal integrity and column heights modelling, therefore reducing volumetric uncertainty,
  • provide a dataset that can be used to help polarise the potential for carbon capture and storage (CCS) in Triassic-Jurassic reservoirs.

This study combines well pressure data with historic and published structural interpretations to generate a pressure cell map for the pre-Cretaceous strata of the UK CNS. A pressure dataset comprising 194 wells was generated from released well data on the National Data Repository (NDR) by Ikon Science Limited (Ikon Science). Pressure cells were interpreted from the well data, based on aquifer overpressure interpretations. Pressure cell boundaries were derived from structural interpretations in the published literature and industry reports.