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Hydrogeochemical modeling of water injection into an oil and gas well under high-pressure high-temperature (HPHT) conditions

Krogulec Ewa, Sawicka Katarzyna, Zabłocki Sebastian

Acta Geologica Polonica

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2020

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Vol. 70, no. 3

419--433

EN

Approximately 80% of water extracted from oil and gas deposits in Poland is disposed of by injection into the rock matrix. The aim of the model research was to predict both the hydrochemical reactions of water injected into wells for its disposal and the hydrogeochemical processes in the reservoir formation. The purpose of hydrogeochemical modeling of the hydrocarbon formation was also to determine the potential of formation waters, injection waters, and their mixtures to precipitate and form mineral sediments, and to determine the corrosion risk to the well. In order to evaluate saturation indices and corrosion ratios, the geochemical programs PHREEQC and DownHole SAT were used. The results of hydrogeochemical modeling indicate the possible occurrence of clogging in the well and the near-well zone caused mainly by the precipitation of iron compounds (iron hydroxide Fe(OH)3 and siderite FeCO3) from the formation water due to the presence of high pressures and temperatures (HPHT). There is also a high certainty of the precipitation of carbonate sediments (calcite CaCO3, strontianite SrCO3, magnesite MgCO3, siderite FeCO3) from the injection water within the whole range of tested pressures and temperatures. The model simulations show that temperature increase has a much greater impact on the potential for precipitation of mineral phases than pressure increase.

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Analiza mikrofacjalna dolomitu głównego (Ca2) we wschodniej części wielkopolskiej platformy węglanowej

Krzyżak Ewelina

Przegląd Geologiczny

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2019

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Vol. 67, nr 3

172--175

EN

Investigation of the Permian Basin in the western part of the Polish Lowland was initiated in 1961 when the Rybaki field was discovered - the first one outside the Carpathians in Poland. The Main Dolomite (Ca2) in the eastern part of the Wielkopolska Platform, located in western Poland, is characterized by a significant variety of microfacies, hence this research is aimed at better interpretation and understanding of depositional environments of current reservoir rocks as well as possibility of identification of facies distribution within the investigated carbonate platform. A detailed microfacies analysis of the Main Dolomite was conducted, which was supported by core logging. The author interpreted depositional environments and generated a 3D model of the top of the Main Dolomite using seismic reflection data. An attempt to correlate microfacies between the analyzed wells was also performed. Integrated analyses of thin sections and drill cores from 4 wells allowed me to interpret the depositional environments of the Main Dolomite. The generated 3D model of the top of the Main Dolomite provided a better insight into subsurface tectonics, paleogeography of the analyzed area and a better understanding of depositional lithofacies environments.

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Złoża węglowodorów w utworach cechsztyńskiego dolomitu głównego (Ca2) na bloku Gorzowa

Czekański E., Kwolek K., Mikołajewski Z.

Przegląd Geologiczny

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2010

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Vol. 58, nr 8

695-703

EN

By discoveries of hydrocarbon deposits in the Polish part of the Southern Permian Basin, Western Poland became a key explorational area. The most spectacular discoveries have been done on the Gorzów Block which borders the Fore-Sudetic Monocline from the south and the Szczecin Swell from the north. This is the area where the biggest oil field - Barnówko-Mostno-Buszewo (BMB) - have been discovered and the group of oil and gas deposits Lubiatów-Międzychód-Grotów (LMG). Detailed litho- facies analysis of Main Dolomite carbonates and seismic surveys (mainly 3D) contributed to good recognition of depositional architecture in this part of the Main Dolomite basin. An interesting issue is the relationship of the discovered deposits with carbonate depositional zones and diverse chemical composition of hydrocarbons. Most of deposits is related to carbonate platforms and microplatforms. Less important are platform slopes but basinal zone is and was considered as the area where source rocks occur. Discovery of the Lubiatów oil deposit at the foot of the Grotów Peninsula opened new possibilities in searching for hydrocarbons. Later negative results of drillings in this zone did not affected the fact that there are still explorational hopes for this type of carbonates. Hydrocarbons which can still be discovered in this interval are still not known based on calculations done in the recent years. It seems, that better geochemical recognition and advanced look on diagenetic evolution and depositional architecture will bring about new discoveries in the Main Dolomite interval on the Gorzów Block.

4

Kryteria identyfikacji obiektów litofacjalnych jako potencjalnych pułapek złożowych w utworach dolomitu głównego (Ca2) u podnóża platform i mikroplatform węglanowych w środkowo-zachodniej Polsce

Kwolek K., Mikołajewski Z.

Przegląd Geologiczny

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2010

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Vol. 58, nr 5

426-435

EN

In terms of oil reserves of Poland, the Lubiatów oilfield in the Międzychód area is the second largest after BMB oilfield. The discovery of this structural-lithological trap in a toe-of-slope position in relation to the Main Dolomite (Ca2) carbonate platform opened a new hydrocarbon opportunities in this unit. One of the conditions for trap occurrence in the "Lubiatów-type" deposits of the toe-of-slope zone in relation to Ca2 carbonate platforms and microplatforms is the presence of appropriate reservoir facies. These facies are characterized by occurrence of thick packets of porous Main Dolomite rocks (Ca2 lithosomes) composed mostly of sublittoral, redeposited carbonate sands (packstones, floatstones, sporadic rudstones), deposited below wave-base and resulting from activity of traction and suspension currents and gravity flows. The only method to detect such facies is via high resolution seismic images, preferably from three-dimensional (3D) surveys. Unfortunately, intensive exploration studies carried out in this zone between 2005-2008 did not bring measurable effects, that is discovery of new hydrocarbon deposits. Several boreholes drilled in Ca2 lithosomes found water-bearing horizons only. In several other dry holes, none of the facies assumptions made prior to drilling were confirmed. Comparison of seismic images of area of those dry holes made it posssible to find a geometric criterion for seismic detection of Ca2 lithosomes located at the toe-of-slope of carbonate platforms and microplatforms. This geometric criterion, along with the seismological one, should constitute an important interpretational premise in identifying or excluding areas with potential hydrocarbon traps in the Main Dolomite rocks in the area under study.

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Generation potential of the Zechstein Main Dolomite (Ca2) carbonates in the GorzówWielkopolski-Miedzychód-Lubiatów area: geological and geochemical approach to microbial-algal source rock

Kotarba M., Wagner R.

Przegląd Geologiczny

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2007

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Vol. 55, nr 12/1

1025-1036

EN

Source rocks of microbial-algal origin commonly occur in the Main Dolomite strata in the Gorzów Wielkopolski-Miedzychód-Lubiatów area on carbonate platform slopes and on carbonate platforms. Oil-prone type II kerogen dominates with occasional amounts of type III or type I kerogens. Hydrocarbon generation processes followed two pathways. In the first pathway, generation was a single-stage process with full generation of hydrocarbon mass in a continuous progression of organic matter transformation, in late Triassic time. In the second pathway, the generation took place in two stages. Eighty to ninety percent of hydrocarbon mass was generated from kerogen by the end of the Jurassic period and the remaining generation was completed during post-Cretaceous time. As a consequence, oil accumulated in traps at the turn of the Triassic- Jurassic periods, and gas saturation of oil accumulations took place by late Jurassic time, with the final gas generation in the Paleogene or Neogene time. Hydrocarbons migrated only a few kilometres from source rocks to reservoir rocks within the Main Dolomite strata.