Visible–Near-Infrared Spectroscopy by Downhole Fluid Analysis Coupled with Comprehensive Two-Dimensional Gas Chromatography To Address Oil Reservoir Complexity

Abstract

One of the largest problems facing the oil industry today is to characterize fluid and architectural complexities of oil reservoirs. This applies particularly in the development of offshore fields where reservoir reconnaissance is impeded by the high costs of wells, often exceeding $100 million. As such, new methods are being developed to address these complexities. Downhole fluid analysis (DFA) is a new method of in-situ fluid characterization used to understand the heterogeneous distributions of hydrocarbon fluids in the reservoir and to identify which crude oils merit subsequent analysis in the laboratory. Comprehensive two-dimensional gas chromatography (GC×GC) is a powerful new method to analyze complex hydrocarbon mixtures such as crude oils and, especially when combined with mass spectroscopy, to elucidate explicit chemical structures. Here, we explore the protocol of DFA coupled with GC×GC to address reservoir complexities.

Features for non-targeted cross-sample analysis with comprehensive two-dimensional chromatography

“…Mullins et al [91] used seven large regions to characterize compound groups in downhole fluid analysis with GC × GC-FID and GC × GC-TOFMS. They plotted ratios of the summed peak intensities within each region in a spider diagram to visualize similarities and differences.…”

Using comprehensive two-dimensional gas chromatography to explore the geochemistry of the Santa Barbara oil seeps

“…However, based on considerations of volatility, evaporation is unlikely to affect significantly compounds less volatile than ~ n-C 16 , in good agreement with the results presented in Figures 10 and the timescale for transport and deposition. Wardlaw et al (2008) noted no significant dissolution of hydrocarbons for freshly seeped oils, but the exposure time was much shorter than for these oils, and it seems likely that the more polar polycyclic aromatic hydrocarbons (PAHs) gradually dissolve into seawater during slick migration and after deposition.…”

Analysis of petroleum compositional similarity using multiway principal components analysis (MPCA) with comprehensive two-dimensional gas chromatographic data

“…Four of the five samples were acquired from an open hole well using the MDT TM tool [47][48][49], which has a stout tube that presses against the borehole wall to establish hydraulic communication with the permeable zone of interest. A rubber packer around the probe creates a hydraulic seal against the mud cake formed by the drilling mud, reducing the potential for contamination by borehole fluids.…”

“…Six oil samples were analysed by GC × GC-FID (Table 1). Two sample pairs were collected in situ by a Modular Formation Dynamics Tester (MDT TM ) tool [47][48][49]. The first pair, labelled F-1 and F-2 was collected within the same well at the same depth and should constitute the same crude oil.…”