TAMING THE THUNDER HORSE WITH AXES AND VECTORS

2021 ◽  
Author(s):  
Bernd Ruehlicke ◽  
◽  
Andras Uhrin ◽  
Zbynek Veselovsky ◽  
Markus Schlaich ◽  
...  
Keyword(s):  
Middle Miocene ◽  
Reservoir Characterization ◽  
Drilling Fluids ◽  
Formation Pressure ◽  
Reservoir Sandstones ◽  
Gravity Driven ◽  
Borehole Image ◽  
Borehole Image Logs

The Thunder Horse Field targets Middle Miocene deepwater turbiditic reservoirs. Despite of being prolific, the mapping of the ~180 m thick, partly amalgamated reservoir sandstones is challenging. Seismic quality is reduced by the presence of salt structures. The salt overburden and high formation pressure requires the use of heavy mud weights and oil-based drilling fluids, which limit the resolution and interpretation potential of borehole image logs (BHI). Halokinetic movements caused significant post-depositional deformation of the already complex gravity- driven sediment stack and the reservoir beds drape against an E–W oriented salt wall. Consequently, the assessment and removal of the structural dip component is not trivial and the evaluation of paleo-transport directions is considerably more complicated compared to undisturbed deepwater reservoirs. The intention of this paper is to bring the main results from Henry et al. (2018) into context with the eigenvector methodology from Ruehlicke et al. (2019) and to emphasize its value for reservoir characterization.

Taming the Thunder Horse With Axes and Vectors

2021 ◽  
Vol 62 (6) ◽  
pp. 630-635
Author(s):  
Bernd Ruehlicke ◽  
◽  
Andras Uhrin ◽  
Zbynek Veselovsky ◽  
Markus Schlaich ◽  
...  
Keyword(s):  
Mass Transport ◽  
Middle Miocene ◽  
Drilling Fluids ◽  
Formation Pressure ◽  
Depositional Settings ◽  
Reservoir Sandstones ◽  
Gravity Driven ◽  
Borehole Image ◽  
Borehole Image Logs

The Thunder Horse Field targets Middle Miocene deepwater turbiditic reservoirs. Despite being prolific, the mapping of the ~180 m thick, partly amalgamated reservoir sandstones is challenging. Seismic quality is reduced by the presence of salt structures. The salt overburden and high formation pressure require the use of heavy mud weights and oil-based drilling fluids, which limit the resolution and interpretation potential of borehole image logs (BHI). Halokinetic movements caused significant post-depositional deformation of the already complex gravity-driven sediment stack, and the reservoir beds drape against an E-W oriented salt wall. Consequently, the assessment and removal of the structural dip component are not trivial, and the evaluation of paleo-transport directions is considerably more complicated compared to undisturbed deepwater reservoirs. This paper illustrates the potential of eigenvector methods to BHI from Ruehlicke et al. (2019) for reconstructing the depositional slope and the architecture of mass transport complexes in the case of chaotic depositional settings and uncertain structural dip. Figures from Henry et al. (2018) are used wherein part axial analysis was performed on data from a group of Thunder Horse wells and presented in more detail.

Direct TOC Quantification in unconventional Kerogen-rich Shale Resource Play from Elemental Spectroscopy Measurements: A Case Study from North Kuwait

2015 ◽  
Author(s):  
Girija K. Joshi ◽  
Mihira N. Acharya ◽  
Marie Van Steene ◽  
Sandeep Chakravorty ◽  
Christophe Darous ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Gamma Ray ◽  
Horizontal Wells ◽  
Final Analysis ◽  
Total Carbon ◽  
Empirical Estimation ◽  
New Type ◽  
Borehole Image ◽  
Borehole Image Logs

Abstract The deep organic-rich calcareous Kerogen of North Kuwait, a continuous 50ft thinly alternating carbonate – organic-rich argillaceous sequence, is not only a source rock but has gained importance as potential reservoirs themselves of typical unconventional category. Resource play or Kerogen characterization relies on quantifying total organic carbon (TOC) and estimating accurate mineralogy. This paper describes the first attempt to directly measure total organic carbon of the Limestone-Kerogen sequence. For the present study, empirical estimations of TOC have been carried out based on conventional log measurements and nuclear magnetic resonance (NMR). The introduction of a new neutron-induced capture and inelastic gamma ray spectroscopy tool using a very high-resolution scintillator and a new type of pulsed neutron generator for the deep unconventional kerogen resources have provided a unique opportunity to measure a stand-alone quantitative TOC value using a combination of capture and inelastic gamma ray spectra. In this process, Inorganic Carbon Content (ICC) is estimated by using elemental concentrations measured by this logging tool in addition to measuring Total Carbon, and this value is subtracted from the measured total carbon to give TOC. The advanced elemental spectroscopy tool measurements were first used to determine accurately the complex mineralogy of the layered carbonate and organic-rich shale sequence. Extensive laboratory measurements of core / cuttings data were used to calibrate the petrophysical evaluation and capture the heterogeneity seen on borehole image logs. The final analysis shows considerable improvements compared to conventional empirical estimation. Once the mineralogy is properly determined, the log-derived TOC matches very well with core measured TOC. This technique has provided a new direct and accurate log-derived TOC for Kerogen characterization. The application has a potential to be used for CAPEX optimization of the coring in future wells. This technique can also be applied in HPHT and High-angle horizontal wells, which can overcome challenging coring difficulties in horizontal wells.

scholarly journals The Use of Borehole Imaging Logs to Optimize Horizontal Well Completions in Fractured Water-flooded Carbonate Reservoirs

GeoArabia ◽  
1997 ◽  
Vol 2 (1) ◽  
pp. 19-34
Author(s):  
Rashid Al-Busaidi
Keyword(s):  
High Water ◽  
Carbonate Reservoirs ◽  
Production Performance ◽  
Seismic Resolution ◽  
Fractured Zones ◽  
Fracture Systems ◽  
Water Breakthrough ◽  
Borehole Image ◽  
Borehole Image Logs

ABSTRACT Early water breakthrough has occurred in the Lower Cretaceous carbonate reservoirs (Aptian Shu’aiba Formation) in Yibal and Lekhwair fields, north Oman. Borehole Image logs were run in more than 10 horizontal wells in each field to investigate the role of faults and fracture systems, as well as facies variations and sedimentary features. These logs indicated the presence of highly-fractured zones with both open and cemented fractures. The fractures have orientations consistent with fault patterns interpreted from 3-D seismic data. High density fractured zones, in most cases, correspond to faults, some of which are below seismic resolution. The presence of fractures and/or fracture zones is the primary cause of early water breakthrough. Improved production performance was achieved by perforating non-fractured intervals to avoid early high water cuts.

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