Hybrid Seismic Attribute Analysis: A New Exploration Approach for the Shallow Emerging Play in Kuwait

Abstract

Till recently Lower Fars formation in Kuwait was associated with heavy oil in Ratqa area only. There had been sporadic drilling for heavy oil exploration over Sabriyah and Bahrah structures with limited success and data. As a part of new exploration initiatives, a deliberate search for new oil from Lower Fars in NE Kuwait is taken up recently. However, devoid of well data and poor shallow seismic imaging, identifying and characterizing of this Lower Fars play, with depths ranging from 400 to 1200ft, was highly challenging due to its complex entrapment. To mitigate this challenge, an unconventional integrated approach had been adopted by correlating the oil/gas shows in mudlogs with seismic data through a hybrid combination of seismic attributes as well as waveform classification. A comprehensive study of hydrocarbon indications from the mud logs of more than 200 deeper wells suggested a prospective corridor with limited structural control and the play primarily appeared to be strati-structural in nature. This was further validated by series of seismic attributes including RMS Amplitude, Phase, Frequency and Sweetness, which were generated over a high amplitude anomalous body identified in shallow seismic data. Advanced seismic attributes like Spectral Decom and Wave form classification over this anomalous seismic event clearly shows a geobody feature, which is in agreement with the prospective corridor identified from the mud log data. The six wells drilled over this geobody proved to be oil bearing and encountered thick pay sands. Post drill integrated study of well logs, core analysis blended with seismic attributes provided insight to better define depositional environments and paleo flow directions, evaluate reservoir quality, as well as to understand possible trapping mechanism. Internal segmentations and lithological variations encountered in the well at the target zone are captured in the response pattern character of the seismic attributes and Waveform classification study confirms the geometry, subsurface lithology and facies variations, which are correlatable to the model from well data. The oil discovered has a sizable volume of better API (>16°) and became a target for cold production. This exploration approach has successfully established the shallow Lower Fars play and based on the model a fast track development drilling is in progress, which resulted in successful addition of new oil to KOC with in a span of less than 3 years from discovery.

AAPG Datapages/Search and Discovery Article #90364 © 2019 AAPG Middle East Geoscience Technology Workshop, Integrated Emerging Exploration Concepts: Challenges, Future Trends and Opportunities, Dhahran, Saudi Arabia, December 2-4, 2019