Guney Formation Oil Reservoir Rock Characterization, Eregli- Ulukisla Basin Ayfer ÖZDEMİR

CONTENT Aim Why? Study Area Geology of the study area Petroleum Reservoir Rock Properties of Guney Formation Petrographic Examinations Reservoir Rock Analyses Diagenetic steps of the Guney Formation Results

Aim to demonstrate petroleum reservoir rock properties of Guney formation in Eregli-Ulukisla Basin in Turkey

Study Area

Why? Eregli-Ulukışla basin is related to Tuz Golu Basin. The studies of hydrocarbon investigation in Tuz Golu Basin have yielded positive results until now, and The previous studies indicated that there was occurence of natural gas There can be hydrocarbon potential in Ereğli-Ulukisla basin The previous studies indicated that Ciftehan, Halkapınar and Hasangazi formations in Eregli-Ulukısla Basin have poor-medium petroleum source rock properties Guney formation is laterally transitive to Hasangazi formation which carries petroleum source rock properties. TOC analysis results of Guney formation below 0.5% represents that Guney Formation can not be evaluated as a petroleum source rock Sedimentary rock properties of formation The formation is a typical turbiditic formation (petroleum source rock properties, reservoir rock ).

Geology

North South

PETROLEUM RESERVOIR ROCK PROPERTIES OF GUNEY FORMATION Petrographic Examinations

Map of samples

Petrographic examinations on Guney formation’s sandstones Sample number Grain length Min- Max(mm) Average grain length(mm) Grain roundnesssorting Type of contact Cement type %Porosity type AÖ-1 0,2-10,4Less sortedmediumtangentialClay %10Inter grain AÖ-12 0,4-51,2Less sortedworseexactClay %3Inter grain AÖ-16 0,3-72,2Less sortedworsetangentialClay+Carb. %10Inter grain AÖ-17 1,2-41,2Less sortedwellexactClay %3Inter grain AÖ-20 0,3-3,80,8sortedmediumtangentialCarbonate%8Inter grain AÖ-22 0,4-6,71,2Less sortedworsetangentialCarbonate%10Inter grain AÖ-23 0,9-10,32,2sortedworseexactClay %4Inter grain AÖ-24 0,4-7,32,4sortedmediumtangentialClay %3Inter grain AÖ-25 1,2-134,3Less sortedworsetangentialCarbonate%4Inter grain AÖ-27 0,5-2,20,8sortedmediumtangentialClay %10Inter grain Ö3 0,2-0,40,2Less sortedworsetangentialClay +Fe %10Inter grain Ö7 0,3-120,6Less sortedmediumexacttangentialClay %6Inter grain Ö10 0,5-121,3Less sortedworsetangentialClay %13Inter grain Ö12 0,2-1,20,4Less sortedworseExactangentialClay %4Inter grain Ö15 0,4-1,40,6sortedwelltangentialClay %4Inter grain Ö34 0,6-2,41,4Less sortedmediumtangentialClay %4Inter grain

Image of petrographic examinations a c b d

Root grain of Guney Formation’s sandstones Sample Number %Qt%Qm%Qp%F %rock fragment %Other mineral AÖ AÖ AÖ AÖ AÖ AÖ AÖ AÖ AÖ AÖ AÖ AÖ Ö Ö Ö Ö Ö Ö Ö Ö Ö

As a result of the petrographic examinations of the Guney formation, the sandstones are feldspar liticharenite and liticharenite (figure 5) with respect to Folk et al., 1970.

PETROLEUM RESERVOIR ROCK PROPERTIES OF GUNEY FORMATION Reservoir Rock Analyses

Permeability-porosity analyses of Guney formation Sample number Porosity values % Permeability values (md) Gas permeabilityFluid Permeability Ö-37,750,670,4 Ö-713,420,460,4 Ö-10 0,240,2 Ö-119,750,390,32 Ö-129,060,310,2 Ö-1424,480,710,4 Ö-1528,740,550,4 Ö-1631,664,654,4 Ö-1929,110,770,2 Ö-2220,38 Ö-3415,862,212,2 Ö-3631,790,910,5 Ö-3834,370,620,3 AÖ-16,440,320,22 AÖ1211,7319,1413 AÖ-1617,4426,8522 AÖ-1735,14 AÖ-2010,77 AÖ-222,84 AÖ-2318,5624,9619,2 AÖ-2414,7135,833 AÖ-2515,812,9311 AÖ-2714,944,494,3

Reservoir rock evaluation Porosity (%)Permeability (md)Evaluation Not important Medium good best Reservoir rock evaluation (Levorsen, 1967)

PETROLEUM RESERVOIR ROCK PROPERTIES OF GUNEY FORMATION Diagenetic evaluation of Guney Formation

The diagenesis processes on the Guney formation sandstones were observed lithification and authigenesis.

Results  Guney Formation sandstone grains showed less-angular roundness and medium-worse sorting properties  Porosity-permeability values were affected negatively by worse sorting and less- angular roundness  Pore spaces in the sandstones were reduced by  clay cement,  ferric-oxides cement,  altered rock fragments and  recryctalization of quartz minerals  Although the results of porosity-permeability analyses show Guney formation has worse reservoir rock properties, the sandstones samples taken from canal fillings in the study area indicate medium-well petroleum reservoir properties due to have high porosity-permeability values.  According to petrographic examinations and the porosity-permeability analyses, the Guney formation shows worse petroleum reservoir properties.

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