Abstract: Impact of the Application of Sequence Stratigraphy on Reservoir Management: A Retrospective Analysis of Field Development and Depletion Experiences

Marianne T. Weaver

To better understand the impact of the application of sequence stratigraphy on field development and depletion, Exxon initiated a project that examined the use of this technology in the reservoir management of many of the corporation's major oil and gas fields. Analysis of Exxon's experience consisted of the evaluation of 58 fields, documentation of individual case studies, and the completion of a cost/benefit analysis for two production affiliates. The results of this analysis demonstrate that there are quantifiable benefits and reservoir management improvements resulting from the proper use of sequence stratigraphy during all stages of field development, including appraisal, initial, mature, and final depletion stages. The documented benefits include reserve additions a competitive finding costs, depletion cost savings, and development of improved reservoir surveillance tools. These benefits can be very large when the sequence stratigraphic studies are fully integrated with additional field data and interpretations, and the fields selected for study meet the appropriate criteria.

In older fields, with large remaining reserves in place, the application of this technology can provide a better understanding of complex reservoir distribution and a method to improve primary, secondary, and tertiary recovery. For example, in a North Sea field, the development of a detailed, sequence stratigraphic framework has led to the development of new and accurate maps and procedures to monitor contact movement and improve reservoir surveillance capabilities, resulting in the identification of bypassed oil. In new fields, optimizing the number and placement of development wells can provide significant investment savings and can potentially lower operating costs. When correctly applied at the appropriate stage of field development, fully integrated, sequence stratigraphy field s udies will result in obtaining maximum ultimate hydrocarbon recovery at the lowest full-life cost.

AAPG Search and Discovery Article #90948©1996-1997 AAPG Distinguished Lecturers