Abstract The Taq Taq Field is located within an anticline in the gently folded zone of the Zagros mountains, northeastern Iraq, approximately 50 km ESE of Erbil. The main reservoirs are fractured limestones and dolomites of Late Cretaceous age, with an oil column exceeding 500 m in thickness. Eocene limestones and dolomites at shallow depth form a subsidiary reservoir. The structure is a gentle thrust-related fold which has also been affected by dextral transpression. A pervasive fracture system is present within the reservoirs, giving good connectivity and deliverability. Initial discovery and appraisal was made in 1978 when three wells were drilled. The recent appraisal programme started in 2005 and by the end of 2008 two seismic surveys had been acquired and eight additional wells had been drilled. Mapping has incorporated a seismic principal component analysis for horizon and lithology identification. Modelling of the fractures has utilized a comprehensive data set derived from core and image logs. Special core analysis has been directed towards the understanding of the pore system and its interaction with the fractures. Synthesis of all these elements is performed in a dual-media dynamic model which is currently in use for development planning.

Abstract Outcrop studies integrated with subsurface data of core, cuttings and different well logs were used to investigate reservoir characteristics of the Middle–Late Eocene Pila Spi Formation at Taq Taq oil field of Kurdistan Region of northeastern Iraq. Reservoir studies include petrographic investigations, microfacies analyses and petrophysical evaluation in an attempt to provide an insight regarding the reservoir potential. The Pila Spi Formation is subdivided into four distinctive lithofacies (P1–P4), characterized by dolostones, dolomitic limestones and limestones. Several types of dolomite were recognized ranging from early diagenetic fenestral fine crystalline to late diagenetic coarse crystalline dolomite, which had positively influenced the reservoir characteristics by enhancing inter-crystalline, intra-skeletal and micro-vug porosity, especially for lithofacies units P2 and P3. Reservoir porosity is heterogeneous in distribution and ranges from 5 to 20%. Using porosity cut-off values of 8.2%, and water saturation cut-off values of 24%, six porosity units were identified from top to bottom (PU1–PU6). The best unit is PU2 (15 m thick), which is characterized by medium crystalline dolomite mosaic with average effective porosity of 21.5%. Permeability ranges between 0.1 and 1 md. Flow unit differentiation is discussed in term of porosity–permeability cross-plot and reservoir pore-throat classification (R35). Results indicate that most of the Pila Spi reservoir is of micro-port (matrix) flow type. However, reservoir quality enhancement is attributed to fracturing.

Abstract North Africa and the Middle East hold huge reserves and resources of oil and gas and are some of the most important regions for future hydrocarbon production. Recent drilling successes onshore Algeria and offshore Egypt, and renewed industry interest in Libya have re-invigorated exploration in North Africa. The Middle East holds the majority of the world's remaining oil and gas and offers a showcase for new research into the major plays and recent exploration/production advances. The North Africa and Middle East session at the 7th Petroleum Geology Conference brought together 12 papers ranging from keynotes on regional play evaluation to detailed field studies. Ten of those papers are published in this volume.