A multiple-point stochastic-based turbidite lobe architecture geomodeling: A case study from L Oilfield, Lower Congo Basin, West Africa

Abstract

As a prominent component of turbidite deposition systems, turbidite lobe internal architecture characterization has proven essential due to its complicated sedimentary hierarchy and evident heterogeneity. This paper demonstrates an integrated methodology for doing a multiple-point stochastic (MPS) simulation of deepwater turbidite single-lobe architecture. Based on the logging data, high-frequency seismic data, thorough architectural feature analysis, and 3D training image, MPS-based geologic modeling of the Miocene turbidite lobe reservoir in the Lower Congo Basin is carried out. This effort has two objectives: (1) to expand the geologic knowledge base of deepwater turbidite lobes with morphology parameters and (2) to develop a process of turbidite geomodeling that could characterize the architectural hierarchy of a single lobe with limited difficult data. As a first step, we analyze and characterize properties of the single-lobe element characteristics and the manner of sedimentary dispersion using 145 m long cores, well logging, and seismic analysis. Second, shallow seismic-based turbidite lobes pick-up and morphology parameter measurements have been conducted to collect quantitative characteristics of turbidite lobe and will be used as geomodeling guidance. Third, a 3D lobe complex training image with single-lobe architecture elements superposition is derived by a seismic geobody caving (using threshold truncation) and enhanced based on the sedimentary distribution mode. An MPS simulation incorporating well data, morphological parameters, training image, and seismic inversion constraint is then performed, which results in obtaining an architecture model that could describe a single lobe. The simulation results generally followed the lobe architecture elements morphology and superposition. The coincidence between the MPS simulated turbidites lobe complex architecture model and the posterior well could reach up to 86%. The paper gives the methodology for a case study that proved the implementation of single turbidite lobe architectural characterization using an MPS, and the recommended process could be applied to other fields.