Search Results

You are looking at 1 - 2 of 2 items for

  • Author: Michał Maruta x
Clear All Modify Search
Open access

Roman Semyrka, Michał Maruta and Andrzej Pasternacki

Abstract

The carbonate reservoirs are anisotropic environments in terms of both the quantitative and qualitative evaluations of pore space. The oil-and-gas-bearing Main Dolomite horizon shows diversified lithology, facial development and thickness resulting in complicated, fluid capacity-fluid filtration system. This system influences both the evaluation and exploration perspectives in the Zechstein Main Dolomite (Ca2) from the Gorzów-Pniewy area. In order to clarify this problem and to determine the hydrocarbon accumulation perspectives, analysis of petrophysical parameters based upon the porosimetric measurements was carried on for the Main Dolomite in the study area, where oil and gas accumulations were discovered. The results of porosimetric measurements clearly indicate the heterogeneity of petrophysical parameters of the Main Dolomite referred to lithologically diversified palaeogeographic zones distinguished in the study area. Such analysis, including the hydrocarbon storage capacity of the Main Dolomite, enabled us to evaluate the possible hydrocarbon accumulation related to generation potential of this horizon.

Open access

Stanisław Dubiel, Adam Zubrzycki, Czesław Rybicki and Michał Maruta

Abstract

In the south part of the Carpathian Foredeep basement, between Bochnia and Ropczyce, the Upper Jurassic (Oxfordian, Kimmeridian and Tithonian) carbonate complex plays important role as a hydrocarbon bearing formation. It consists of shallow marine carbonates deposited in environments of the outer carbonate ramp as reef limestones (dolomites), microbial - sponge or coral biostromes and marly or micrite limestones as well. The inner pore space system of these rocks was affected by different diagenetic processes as calcite cementation, dissolution, dolomitization and most probably by tectonic fracturing as well. These phenomena have modified pore space systems within limestone / dolomite series forming more or less developed reservoir zones (horizons). According to the interpretation of DST results (analysis of pressure build up curves by log - log method) for 11 intervals (marked out previously by well logging due to porosity increase readings) within the Upper Jurassic formation 3 types of pore/fracture space systems were distinguished:

- type I - fracture - vuggy porosity system in which fractures connecting voids and vugs within organogenic carbonates are of great importance for medium flow;

- type II - vuggy - fracture porosity system where a pore space consists of weak connected voids and intergranular/intercrystalline pores with minor influence of fractures;

- type III - cavern porosity system in which a secondary porosity is developed due to dolomitization and cement/grain dissolution processes.