Some Evidences for Deep Burial Diagenesis in a Carbonate Reservoir, Case Study

M.M. Althagafy¹ and S. Ozkaya²

Abstract

The objective of this study is to understand the seemingly random and unpredictable distribution of high flow patches in a carbonate reservoir in Saudi Arabia. Vuggy zones were identified on borehole images and mapped in different reservoir units. Overlay maps of high permeability streaks from production logs and high PI and KH envelopes from well tests were also prepared to compare and correlate with vug distribution in the field. The vuggy zones were validated by comparing core and image logs.

Leaching is highly correlated with porosity and some dolomites that have very high porosity. The highest degree of dissolution occurs within high porosity dolomitic layers that have a complex areal distribution pattern. This complex pattern is interpreted as an intricate solution pathway. High K patches mostly fall on these pathways, explaining why their distribution is so irregular and unpredictable.

AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain