Terciérní khurmalské souvrství je lagunový krystalický vápenec, dolomit s vložkami různých klastických hornin. V některých záhonech se také vyskytuje občasný výskyt sádrovce a vzácných plžů, miliolidů a řas. Útvar tvořil dolostone a dolomitický vápenec s vsunutými jílovitými vrstvami mezi zjištěnými vrstvami. které lze považovat za dobrou nádrž z hlediska pórovitosti, zatímco obsah břidlice snižoval kvalitu nádrží těchto jednotek. Útvar má proměnlivou mocnost v celém poli, 99,8 m od severovýchodního okraje a 109 m v jihovýchodním ponoru a v jiné oblasti má různou mocnost. Pórový tlak a kompartmentalizace rezervoárů budou studovány za účelem řízení změn tlaku v karbonátových rezervoárech během průzkumu ropy. Metodu Eaton lze použít k predikci tlaku v pórech z dat zvukového záznamu. Základním předpokladem je vzájemný vztah mezi pozorovanou dobou průchodu z log čtení a normální dobou průchodu, která se nachází na trendu normálního zhutňování (NCT). Objemovou hustotu lze určit ze zvukového logaritmu a ukázat shodu s objemovou hustotou odvozenou z logaritmu hustoty, aby se prokázalo, že zvukový logaritmus lze použít jako dobrou alternativu k získání sypné hmotnosti a následně ke stanovení litostatického tlaku. Pórový tlak závisí na změnách gradientu nadloží a obsahu tekutiny. Na základě předpokládaného tlaku v pórech lze prostor studovaného zásobníku rozdělit na tlakové zóny. Gama-ray log, hustota a neutron log se používají k odhadu pórovitosti a litologické identifikaci. Popisy vzorků hornin a mikroskopické studie tenkých řezů lze také použít ke vzájemnému ověření a ověření pórů z log dat. Studie závisí na práci v terénu, mikroskopických studiích, laboratorním měření pórovitosti a propustnosti a analýze jamek. Metody studia jsou (Digitalizace těžebních dat, Identifikace trendů normálního zhutňování, Stanovení tlaku v nadloží a pórového tlaku, Zhotovování a studium tenkých řezů a Měření pórovitosti a propustnosti vzorků hornin). Záznam gama záření odhalil, že objem břidlice v khurmalském souvrství je 20 %, a křížový graf neutronové hustoty ukázal, že nádrž se skládá převážně z vápence a dolomitického vápence. Model pórovitosti ukázal, že ve spodní části raně třetihorní formace je přítomna dobrá a dobrá pórovitost a propustnost, a model nasycení ukázal, že horní část formace nemá žádný důkaz uhlovodíku, ale jsou přítomny dobře pohyblivé uhlovodíky. Predikce a modelování pórového tlaku na základě sonického logaritmu ukázaly, že k pórovému tlaku ve formaci dochází po hloubce 1550 m a normální trend zhutňování se zvyšuje směrem k větší hloubce formace.
Annotation in English
The Tertiary Khurmala Formation is a lagoonal crystallized limestone, dolomite with interbeds of different clastic rocks. It also contains an occasional occurrence of gypsum and rare gastropods, miliolids, and algae in some beds. The formation comprised dolostone and dolomitic limestone with the intercalation of clay layers between the recognized beds. that can be considered a good reservoir unit in terms of porosity, whereas the shale contents reduced the reservoir quality of these units. The formation has variable thickness throughout the field, 99.8 m from the northeastern limb and 109 m in the southeastern plunge and it has a different thickness in another area. Pore pressure and reservoir compartmentalization will be studied to manage pressure changes in carbonate reservoirs during petroleum exploration. The Eaton method can be used to predict the pore pressure from sonic log data. The basic assumption is the interrelation between observed transit time from log reading and normal transit time that locates on the normal compaction trend (NCT). The bulk density can be determined from the sonic log and show matching with the bulk density derived from the density log to demonstrate that the sonic log can be used as a good alternative to obtain the bulk density and consequently to determine lithostatic pressure. Pore pressure depends upon changes in the overburden gradient and fluid content. Based on predicted pore pressure, the study reservoir compartment can be divided into pressure zones. Gamma-ray log, density, and neutron log are used to estimate porosity and lithology identification. Rock sample descriptions and microscopic studies of thin sections can also be used to validate each other and pores from log data. The study depends on fieldwork, microscopic studies, lab measuring porosity and permeability, and well-log analysis. Study methods are (Digitizing well log data, Identification of normal compaction trends, Determination of overburden pressure and pore pressure, Making and studying thin sections, and Measuring the porosity and permeability of rock samples). The gamma-ray log revealed that the volume of shale in the Khurmala Formation is 20%, and the neutron-density cross-plot showed that the reservoir consists mainly of limestone and dolomitic limestone. The porosity model showed that fair and good porosity and permeability are present in the lower part of the Early Tertiary formation, and the saturation model showed that the upper part of the formation has no evidence of hydrocarbon but good movable hydrocarbons are present. Pore pressure prediction and modeling based on sonic well-log showed that the formation pore pressure occurs after a depth of 1550m, and the normal compaction trend has increased toward more depth in the formation.
Keywords
Pórovitost, Pórový tlak, Studna, Formace Khurmala
Keywords in English
Porosity, Pore Pressure, Well log, Khurmala Formation
Length of the covering note
-
Language
AN
Annotation
Terciérní khurmalské souvrství je lagunový krystalický vápenec, dolomit s vložkami různých klastických hornin. V některých záhonech se také vyskytuje občasný výskyt sádrovce a vzácných plžů, miliolidů a řas. Útvar tvořil dolostone a dolomitický vápenec s vsunutými jílovitými vrstvami mezi zjištěnými vrstvami. které lze považovat za dobrou nádrž z hlediska pórovitosti, zatímco obsah břidlice snižoval kvalitu nádrží těchto jednotek. Útvar má proměnlivou mocnost v celém poli, 99,8 m od severovýchodního okraje a 109 m v jihovýchodním ponoru a v jiné oblasti má různou mocnost. Pórový tlak a kompartmentalizace rezervoárů budou studovány za účelem řízení změn tlaku v karbonátových rezervoárech během průzkumu ropy. Metodu Eaton lze použít k predikci tlaku v pórech z dat zvukového záznamu. Základním předpokladem je vzájemný vztah mezi pozorovanou dobou průchodu z log čtení a normální dobou průchodu, která se nachází na trendu normálního zhutňování (NCT). Objemovou hustotu lze určit ze zvukového logaritmu a ukázat shodu s objemovou hustotou odvozenou z logaritmu hustoty, aby se prokázalo, že zvukový logaritmus lze použít jako dobrou alternativu k získání sypné hmotnosti a následně ke stanovení litostatického tlaku. Pórový tlak závisí na změnách gradientu nadloží a obsahu tekutiny. Na základě předpokládaného tlaku v pórech lze prostor studovaného zásobníku rozdělit na tlakové zóny. Gama-ray log, hustota a neutron log se používají k odhadu pórovitosti a litologické identifikaci. Popisy vzorků hornin a mikroskopické studie tenkých řezů lze také použít ke vzájemnému ověření a ověření pórů z log dat. Studie závisí na práci v terénu, mikroskopických studiích, laboratorním měření pórovitosti a propustnosti a analýze jamek. Metody studia jsou (Digitalizace těžebních dat, Identifikace trendů normálního zhutňování, Stanovení tlaku v nadloží a pórového tlaku, Zhotovování a studium tenkých řezů a Měření pórovitosti a propustnosti vzorků hornin). Záznam gama záření odhalil, že objem břidlice v khurmalském souvrství je 20 %, a křížový graf neutronové hustoty ukázal, že nádrž se skládá převážně z vápence a dolomitického vápence. Model pórovitosti ukázal, že ve spodní části raně třetihorní formace je přítomna dobrá a dobrá pórovitost a propustnost, a model nasycení ukázal, že horní část formace nemá žádný důkaz uhlovodíku, ale jsou přítomny dobře pohyblivé uhlovodíky. Predikce a modelování pórového tlaku na základě sonického logaritmu ukázaly, že k pórovému tlaku ve formaci dochází po hloubce 1550 m a normální trend zhutňování se zvyšuje směrem k větší hloubce formace.
Annotation in English
The Tertiary Khurmala Formation is a lagoonal crystallized limestone, dolomite with interbeds of different clastic rocks. It also contains an occasional occurrence of gypsum and rare gastropods, miliolids, and algae in some beds. The formation comprised dolostone and dolomitic limestone with the intercalation of clay layers between the recognized beds. that can be considered a good reservoir unit in terms of porosity, whereas the shale contents reduced the reservoir quality of these units. The formation has variable thickness throughout the field, 99.8 m from the northeastern limb and 109 m in the southeastern plunge and it has a different thickness in another area. Pore pressure and reservoir compartmentalization will be studied to manage pressure changes in carbonate reservoirs during petroleum exploration. The Eaton method can be used to predict the pore pressure from sonic log data. The basic assumption is the interrelation between observed transit time from log reading and normal transit time that locates on the normal compaction trend (NCT). The bulk density can be determined from the sonic log and show matching with the bulk density derived from the density log to demonstrate that the sonic log can be used as a good alternative to obtain the bulk density and consequently to determine lithostatic pressure. Pore pressure depends upon changes in the overburden gradient and fluid content. Based on predicted pore pressure, the study reservoir compartment can be divided into pressure zones. Gamma-ray log, density, and neutron log are used to estimate porosity and lithology identification. Rock sample descriptions and microscopic studies of thin sections can also be used to validate each other and pores from log data. The study depends on fieldwork, microscopic studies, lab measuring porosity and permeability, and well-log analysis. Study methods are (Digitizing well log data, Identification of normal compaction trends, Determination of overburden pressure and pore pressure, Making and studying thin sections, and Measuring the porosity and permeability of rock samples). The gamma-ray log revealed that the volume of shale in the Khurmala Formation is 20%, and the neutron-density cross-plot showed that the reservoir consists mainly of limestone and dolomitic limestone. The porosity model showed that fair and good porosity and permeability are present in the lower part of the Early Tertiary formation, and the saturation model showed that the upper part of the formation has no evidence of hydrocarbon but good movable hydrocarbons are present. Pore pressure prediction and modeling based on sonic well-log showed that the formation pore pressure occurs after a depth of 1550m, and the normal compaction trend has increased toward more depth in the formation.
Keywords
Pórovitost, Pórový tlak, Studna, Formace Khurmala
Keywords in English
Porosity, Pore Pressure, Well log, Khurmala Formation
Research Plan
The study aims to manage unpredicted pressure changes that occur in wells drilled in the carbonate reservoirs, which are potentially dangerous and financially cost during petroleum exploration. It will study from pore pressure and reservoir compartmentalization points of view. The Eaton method can be used to predict the pore pressure from the sonic log data. The basic assumption for this technique is the interrelation between observed transit time from log reading and normal transit time that locates on the normal compaction trend (NCT). The bulk density can be determined from the sonic log and show matching with the bulk density derived from the density log to demonstrate that the sonic log can be used as a good alternative to obtain the bulk density and consequently to determine lithostatic pressure. Pore pressure depends upon changes in the overburden gradient and fluid content. resistivity log can use to determine fluids in the pores. Based on predicted pore pressure, the study reservoir compartment into pressure zones. The number of the zones can identify by using a graphical method of probability plot of the predicted pore pressure on the basis of cluster analysis. The gamma-ray log would be used for shale content calculation, density, and neutron log is used to estimate porosity and lithology identification. Rock sample descriptions in the field also would be used to identify lithology and microscopic study of thin sections could be used to identify porosity as well as rock core samples and can be used to validate each other and pores from log data. Student´s tasks Khurmala Formation (Paleocene Lower Eocene) was first described by Bellen et al. (1959) in the Kirkuk-114 well were about 185 m thick. According to the same authors, the formation consists of dolomite, sub oolitic in parts, and finely recrystallized limestone. The chemical limestone probably interfingering strongly with material from the Kolosh Formation, which is containing detrital chert, flint, radiolarite, and green rocks of silt and sand size. The above authors have further added that anhydrite, which is probably secondary, occurs occasionally and fossils are obliterated by recrystallization and dolomitization. According to Jassim and Goff (2006), the formation was deposited in a restricted lagoonal environment. The study depends on the fieldwork, microscopic studies, lab measuring porosity and permeability, and well log analysis. In the field, the lithology of the section is described from the base to the top of the sections by the eyes and hand lens. From the sections, the authors take samples according to the change of the lithology for the lab studies. Pore pressures in most deep sedimentary formations are not hydrostatic; instead, they are overpressured and elevated even to more than double the hydrostatic pressure. Eaton's sonic method is then adapted using depth-dependent normal compaction equations for pore pressure prediction in subsurface formations. The adapted methods provide a much easier way to handle normal compaction trendlines. A theoretical pore pressure-porosity model is proposed based on the primary overpressure generation mechanism — compaction disequilibrium and effective stress-porosity-compaction theory. Accordingly, pore pressure predictions from compressional velocity and sonic transit time are obtained using the new theoretical model. - Laboratory works and computations are: - 1- Digitizing of well log data - 2- Identification of normal compaction trend. - 3- Determination of overburden pressure and pore pressure. - 4- Making and studying thin sections. - 5- Measuring porosity and permeability of rock samples. Scope of graphic works: graphic columns of profiles, boards with field photographs, statistical diagrams, photo documentation, taken pictures (maps), or others.
Research Plan
The study aims to manage unpredicted pressure changes that occur in wells drilled in the carbonate reservoirs, which are potentially dangerous and financially cost during petroleum exploration. It will study from pore pressure and reservoir compartmentalization points of view. The Eaton method can be used to predict the pore pressure from the sonic log data. The basic assumption for this technique is the interrelation between observed transit time from log reading and normal transit time that locates on the normal compaction trend (NCT). The bulk density can be determined from the sonic log and show matching with the bulk density derived from the density log to demonstrate that the sonic log can be used as a good alternative to obtain the bulk density and consequently to determine lithostatic pressure. Pore pressure depends upon changes in the overburden gradient and fluid content. resistivity log can use to determine fluids in the pores. Based on predicted pore pressure, the study reservoir compartment into pressure zones. The number of the zones can identify by using a graphical method of probability plot of the predicted pore pressure on the basis of cluster analysis. The gamma-ray log would be used for shale content calculation, density, and neutron log is used to estimate porosity and lithology identification. Rock sample descriptions in the field also would be used to identify lithology and microscopic study of thin sections could be used to identify porosity as well as rock core samples and can be used to validate each other and pores from log data. Student´s tasks Khurmala Formation (Paleocene Lower Eocene) was first described by Bellen et al. (1959) in the Kirkuk-114 well were about 185 m thick. According to the same authors, the formation consists of dolomite, sub oolitic in parts, and finely recrystallized limestone. The chemical limestone probably interfingering strongly with material from the Kolosh Formation, which is containing detrital chert, flint, radiolarite, and green rocks of silt and sand size. The above authors have further added that anhydrite, which is probably secondary, occurs occasionally and fossils are obliterated by recrystallization and dolomitization. According to Jassim and Goff (2006), the formation was deposited in a restricted lagoonal environment. The study depends on the fieldwork, microscopic studies, lab measuring porosity and permeability, and well log analysis. In the field, the lithology of the section is described from the base to the top of the sections by the eyes and hand lens. From the sections, the authors take samples according to the change of the lithology for the lab studies. Pore pressures in most deep sedimentary formations are not hydrostatic; instead, they are overpressured and elevated even to more than double the hydrostatic pressure. Eaton's sonic method is then adapted using depth-dependent normal compaction equations for pore pressure prediction in subsurface formations. The adapted methods provide a much easier way to handle normal compaction trendlines. A theoretical pore pressure-porosity model is proposed based on the primary overpressure generation mechanism — compaction disequilibrium and effective stress-porosity-compaction theory. Accordingly, pore pressure predictions from compressional velocity and sonic transit time are obtained using the new theoretical model. - Laboratory works and computations are: - 1- Digitizing of well log data - 2- Identification of normal compaction trend. - 3- Determination of overburden pressure and pore pressure. - 4- Making and studying thin sections. - 5- Measuring porosity and permeability of rock samples. Scope of graphic works: graphic columns of profiles, boards with field photographs, statistical diagrams, photo documentation, taken pictures (maps), or others.
Recommended resources
Ahmed, Y.K.A., 2008. Carbonate microfacies of Sinjar Formation, at South – West of Sulaimani City,
Al-Barzanji, SH.J., 1989. Microfacies study of the Khurmala Formation from selected sections in the
north and north east Iraq. Unpublished M.Sc. thesis, Salahaddin University, 113pp.