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AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain

Wavelet Consistency Assessment for Quantitative Interpretation - A Case Study from Northeastern Saudi Arabia

Ming-Ren Hong1; Mohammed Alfaraj1; Jinsong Wang2; James Rice3

(1) ETSD, Saudi Aramco, Dhahran, Saudi Arabia.

(2) EASD, Saudi Aramco, Dhahran, Saudi Arabia.

(3) AED, Saudi Aramco, Dhahran, Saudi Arabia.

An onshore exploration 3D survey located in Northeastern Saudi Arabia and covering an area of approximately 6300 square kilometers was acquired in 2003. There are two existing oil fields with Upper Jurassic, carbonate reservoirs controlled by four-way closures, located within the survey. Current exploration activity, away from these fields, is concentrating on stratigraphic plays involving up-dip truncation of regional trends with the hydrocarbon seals being created by dolomitization and cementation within the reservoir.

A multi-well feasibility study confirmed that porosity changes within the reservoir at these seal boundaries could be seen using acoustic impedance inversion. One important question on the use of seismic inversion over this large of an area was the wavelet stability. The inversion software used in the project employed a multi-well, multi-trace approach that allowed for very detailed, thorough and semi-automated procedures for conducting a wavelet study.

This paper will present the results from wavelet stability tests including analysis of seismic data only by means of a Markov chain Monte Carlo (MCMC) simulation technique. This is followed by scenarios with different combinations of single and multiple wells and seismic data, with varying number of traces around each well used in the calibration and wavelet extraction. The final wavelet determined in the inversion analysis was then cross-checked among the various techniques. This thorough procedure confirmed that the wavelet was zero phase and SEG negative polarity, and that it was reasonably stable throughout the survey.