An Innovative Workflow for 3D Quantitative Characterization of Deeply Buried Carbonate Fault-Karstic Migration Carriers of Central Uplift in Tarim Basin

Abstract

The migration carrier is an important component of petroleum system, which offers pathways for hydrocarbon migration and accumulation between source rocks and traps. The Ordovician carbonate fault-karstic carriers are deeply buried (exceed 5500 m) in Central Uplift of the Tarim Basin, with extremely irregularity in scale, geometry and spatial distributions, have strong heterogeneity in transport properties, which increase the difficulty of deep petroleum system analysis and increase the uncertainty of deep hydrocarbon exploration. Therefore, it is very necessary to quantitatively characterize the fault-karstic carriers. Facing the problems of strong heterogenous deep fault-karstic carriers and multistage-multisource hydrocarbon accumulations, this paper used advanced data-driven technology to integrate geology, geophysics and production data, established a geology-geophysics integrated workflow to quantitatively characterize the fault-karstic carriers in the micro-macro-mega scale. (1) Microscopic scale (0.01~0.1 m): Focusing on the effective pore structure in deeply buried carbonate strata and considering the geological processes including sedimentary, diagenetic, and tectonic movements, detailed observations on core samples and thin sections were carried out, and 17 rock types were divided. (2) Macroscopic scale (0.1~10 m): According to the vertical and horizontal resolution and recognition ability of wireline logging data, a classifier from logging data that was conditioned to core data was created, and 16 electrofacies are divided, and then 6 types of carries and their physical properties were obtained. (3) The megascale (10~1000 m): Constrained by the rock types, the electrofacies and the carrier types, a data mining approach was carried on multi seismic attributes, and 7 types of seismic facies of the karstic carriers were recognized. The developments and distributions of karstic carriers inter wells were clarified. Combined with three-dimensional interpretation of strike-slip faults, a three-dimensional fault-karstic carrier framework was established. (4) Fluid property analysis: According to the results of well test, logging interpretations of oil and gas aquifers, combined with well production data, the fluid property in traps and carriers was recognized, and the multi-stage hydrocarbon accumulation processes were reversed, and the impact of fault-karstic carriers on the current fluid distribution was clarified. This workflow integrated the geological understanding, geophysical responses and data mining techniques and achieved a seamless connection between the microscopic-macro-macroscopic scales. The workflow was applied to quantitative characterize the deeply buried fault-karstic carrier and deep carbonate petroleum system analysis, showing a reliable guidance to local oil and gas exploration. The workflow can also be applied to the study of migration carriers in similar paleo-karst reservoirs and clastic reservoirs.

AAPG Datapages/Search and Discovery Article #90340 ©2018 AAPG Geoscience Technology Workshop, Deep and Ultra Deep Petroleum Systems, Beijing, China, October 26-28, 2018