Improved Reservoir Characterization by a Facie based on Rock Mechnical Properties
Author
Drimba, Virgil Roland
Term
4. term
Education
Publication year
2016
Submitted on
2016-01-07
Abstract
This thesis investigates whether reservoir characterization in the Lansing Formation (Rawlins County, Kansas) can be improved by combining petrophysical evaluation with rock-mechanical facies and the identification of hydraulic flow units. The study uses wireline logs from nine wells (gamma ray, density, neutron porosity, sonic, and resistivity) and core data from one well. An initial well-correlation exercise defined nine zones with an average total thickness of about 281 ft. Lithology varies among limestone, quartz, and shales, with a carbonate fraction between 20% and 90%. Petrophysical analysis revealed wide variations in porosity and permeability across zones and indicated that parameters used for water saturation calculations can depend on rock quality. Four mechanical rock facies were identified with decreasing quality ranked 4, 3, 2, and 1. Incorporating facies into water saturation calculations in one well produced errors of 0–30%, suggesting that ignoring rock type can bias saturation estimates. Extrapolating this effect to 206 wells in Rawlins County suggests a potential annual oil production increase of up to 5.6 million barrels. Hydraulic flow units were defined using the Flow Zone Indicator (FZI) concept via the Amafuele equation, integrating Rock Quality Index (RQI) and petrophysical properties; analysis of log FZI (histogram and normal probability plots) indicates six units with a reasonable link to RQI. These results provide more reliable inputs for field-wide simulation and planning for continued development.
Dette speciale undersøger, om reservoirkarakterisering i Lansing Formationen (Rawlins County, Kansas) kan forbedres ved at kombinere petrofysisk evaluering med bjergmekaniske facies og identifikation af hydrauliske strømningsenheder. Der blev anvendt wireline-logs fra ni brønde (gamma ray, densitet, neutronporøsitet, sonic og resistivitet) samt kerneoplysninger fra én brønd. En indledende brøndkorrelation afgrænsede ni zoner med en gennemsnitlig samlet tykkelse på cirka 281 fod. Litologien varierer mellem kalksten, kvarts og skifre, med en karbonatfraktion på 20–90 %. De petrofysiske analyser viste stor variation i porøsitet og permeabilitet mellem zoner, og at parametre til beregning af vandmætning kan afhænge af klippekvalitet. På baggrund af forudsagte bjergmekaniske egenskaber blev der identificeret fire faciestyper med faldende kvalitet (4, 3, 2, 1). Når faciesklassifikationen blev integreret i vandmætningsberegninger i én brønd, blev der observeret fejl på 0–30 %, hvilket antyder, at ignorering af klippetype kan skævvride mætningsestimater. En ekstrapolation til 206 brønde i Rawlins County indikerer en potentiel årlig produktionsstigning på op til 5,6 millioner tønder olie. Hydrauliske strømningsenheder blev defineret ved hjælp af Flow Zone Indicator (FZI) med Amafuele-ligningen baseret på integration af Rock Quality Index (RQI) og petrofysiske egenskaber; analyse af log FZI (histogram og normalfordelingsplot) peger på seks enheder med rimelig kobling til RQI. Resultaterne giver et forbedret grundlag for feltomfattende simulering og planlægning af videre udvikling.
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