FESQ May Seminar in Brisbane

07-May-2018 update:

This event has been cancelled due to administrative circumstances beyond the control of FESAus, FESQ and the speaker.  We regret the inconvenience.  Keep checking or see your email for updates.

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The Problem with Silt in Low Resistivity –Low Contrast Pay ReservoirsAlexander_Balevich, May 2018 FESAus speaker

Presented by Alexander Belevich (Baker Hughes)

Clastic laminated reservoirs have historically posed difficulties for subsurface groups engaged in formation evaluation. Difficulties are largely due to convoluted log responses which preclude accurate assessment of key petrophysical properties such as thin sand bed porosity and water saturation. In South East Asian (SEA) basins the abundance of silt in reservoir and non-reservoir rocks adds another layer of complexity to theformation evaluation and directly affects the design of appropriate data acquisition programs. This presentation describes the silty thin bed problem by assessing the efficacy and uncertainties of various log measurements to arrive at the correct petrophysical solution.


A review of rock physics literature is presented to highlight the underlying reasons for unusual log behaviorin silty facies. Generally, laminated rocks are evaluated from two different approaches: (1) high-resolution or (2) bulk rock volume. Three wells drilled in different sedimentary basins in SEA are presented to demonstrate the theory, challenges, and pitfalls of the most common approaches and techniques.


Use of the Thomas-Stieber and resistivity anisotropy are discussed, along with borehole image and NMR data to contribute to reduce net-to-gross uncertainty or understanding of the reservoir geometry. One very silty to fine-grained sand reservoir in Vietnam, displays anisotropy due to grain-size variation on a very fine level, in addition to the laminar sand-shale phenomenon. In this example, the relevance of shale laminar estimations is questioned and can only be justified with detailed core studies. It is, however, argued that reliable identification of hydrocarbon-bearing silt-rich sequences is only possible with multi-component resistivity data. In addition, quantification of sand lamina resistivity, Rsand, is still possible in these silty sands with variable amounts of irreducible water.

Resistivity anisotropy provides further necessary input for accurate formation evaluation in laminated sand-silt-clay systems. Rv is a key measurement because it is sensitive to hydrocarbons in thinly laminated sands or silts. One very silty to fine-grained sand reservoir in Vietnam, displays anisotropy due to grain-size variation on a very fine level, in addition to the laminar sand-shale phenomenon. In this example, the relevance of shale laminar estimations is questioned and can only be justified with detailed core studies. It is, however, argued that reliable identification of hydrocarbon-bearing silt-rich sequences is only possible with multi-component resistivity data. In addition, quantification of sand lamina resistivity, Rsand, is still possible in these silty sands with variable amounts of irreducible water.

Although many papers discuss the thin-bed formation evaluation problem, very few publications address issues related to laminated sand-silt-clay reservoirs. This paper partly addresses this literature scarcity. Identification and accurate quantification of silt-rich laminated reservoirs is of critical importance in basins with a high proportion of silt.

About the presenters

Alexander Belevich is a Petrophysics Advisor at Baker Hughes.  Graduated from Kuban State University in Russia with Formation Evaluation University Degree. Worked in various locations in Russia (Siberia, above the Arctic circle and Moscow), then spent 4 years in Vietnam and has been working in Malaysia for the last 3 years in Asia Pacific regional advisor and support role. Petrophysicist covering formation evaluation of WL vs LWD open hole logs, thin bed evaluation, identification and evaluation of LRLC reservoirs. Has special interest in interpretation of NMR and 3D Resistivity logs, data integration, acquisition program design.

Alexander is a SPWLA 2017-2018 Distinguished Speaker.  The SPWLA Distinguished Speaker Program provides local Chapters a contact list of persons in high industry regard who are able and willing to speak on certain topic(s) of interest at local chapter meetings.

Registration deadline: Thursday 10th May 2018 3 PM

Tell your colleagues about this event with the flyer!

 

May 10th, 2018 3:30 PM   through   5:00 PM
Santos Place
Level 22
32 Turbot Street
Brisbane, QLD 4000
Australia

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