LITHOFACIES ASSOCIATION, DOLOMITIZATION, AND POTENTIALITY OF THE PILA SPI FORMATION,   TAQ TAQ OIL FIELD, KURDISTAN REGION, NE IRAQ

A. Al-Qayim, Basim; H. Othman, Divan

	LITHOFACIES ASSOCIATION, DOLOMITIZATION, AND POTENTIALITY OF THE PILA SPI FORMATION, TAQ TAQ OIL FIELD, KURDISTAN REGION, NE IRAQ
Iraqi Bulletin of Geology and Mining
Article 1, Volume 6, Issue 2, 2010, Pages 95-114
Authors
Basim A. Al-Qayim; Divan H. Othman
Abstract
Subsurface data of four oil wells from the Taq Taq oil field of Northeast Iraq, in addition to one surface section from the near by Haibat Sultan Mountain were selected to study the lithofacies associations of the Pila Spi Formation. Detailed investigation of rock samples, cuttings, cores and wire-line logs is attempted to identify lithologic units and association, and to evaluate dolomitization effect on these rocks and its contribution to the reservoir quality. The formation, in this area is subdivided into four distinctive lithologic units, from bottom to top are: Lower Brecciated and Silicified Unit (P1), Dolomitized Tidal Flat Limestone (P2), Lagoonal Limestone and Dolostone (P3), and Upper Brecciated Dolomitic Limestone (P4). These rocks were variably affected by diagenesis and intensively modified by dolomitization, which is drastically overprinted the original fabrics and components. Several types of dolomite were recognized including: Fenestral Fine Crystalline Dolomite (D1), Fine Crystalline Planar-e to Planar-s Dolomite (D2), Fine Crystalline Non-planar Dolomite (D3), Medium Crystalline Non-planar Dolomite (D4), and Coarse Crystalline Dolomite (D5). Dolomitization had positively influenced the reservoir characteristics by enhancing inter-crystalline porosity, and developing intra-skeletal and moldic porosity, which evolve into the common micro-vug porosity, especially, in the middle lithologic units (P2 and P3). Reservoir flow potentiality, however, is greatly enhanced by the secondary fracture porosity.

Statistics Article View: 82 PDF Download: 62