Koray Yilmaz, Burc Umul and

Gary Nilson, Transatlantic Petroleum, Ltd.

August 2015

New Tight Gas Development in the Mezardere Formation, Thrace Basin Turkey.

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Absract

To better exploit unconventional resources, TransAtlantic

Petroleum, Ltd. have applied the “Asset Team” development

approach. Geologists, geophysicists, engineers, log analysts, and

etc. combined skills and insight to better understand, measure and

predict reservoir properties in low-permeability reservoirs and to

use that information in resource evaluation, reservoir

characterization and management. This paper showcases the

strategy used to expand the economical recoverable gas resources

within the leasehold areas of TransAtlantic Petroleum, Ltd. in the

Thrace Basin, located in western Turkey.

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TransAtlantic Petroleum, Ltd. Thrace Basin Leases

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Thrace Basin – Mesardere Structure Map

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Tekirdag, Kayi Area– Thrace Basin, Turkey

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Thrace Basin Stratigraphic Column

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Teslimkoy fm. outcrops

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Tekirdag, Kayi, Yagci Area, structure & faults

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Location of early Horizontal wells in Tight Sands

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Correlations of frac candidate zones across field

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Log & Mudlog – Typical Tight Gas Sand Frac Candidate

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Formation Water Resistivity

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Log of “Tight Gas” Zone

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Core Analyses – Lithology from X-Ray Diffraction

Table 2. Bulk fraction X-Ray diffraction data for full diameter core sample from Teslimkoy tight sandstone reservoir, Baglik-1 well. Table includes weight percentage mineralogy.

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Core Analyses – XRD – Clay Analysis

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Ternary Diagram – Teslimkoy fm. Baglik - 1

Figure 6. Ternary classification (Q, F, R) diagram, for

Teslimkoy formation, full diameter core in Baglik-1 well. Point counting identified Teslimkoy sandstones as

feldspathic litharenites.

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Ternary Porosity Diagram

Figure 7. Porosity sandstone classification diagram for the

Teslimkoy core in Baglik-1 showing that the majority of observed

thin section porosity is microporosity.

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Porosity & Permeability Under Variable Stress

Figure 8. Core porosity vs. air permeability at hydrostatic pressures of 800, 1200 & 1700 psi from plug core samples taken from 910-915 m. depth. See Legend for color code related to net over burden pressures (NOB).

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Petrophysical Saturation Exponents/Constants

Formation Initial Trial Final Correlation

Teslimkoy a=1.0; m=1.63; n=1.96 a=1.0; m=1.77; n=1.75

Kesan a=1.0; m=1.83; n=1.78 a=1.0; m=1.83; n=1.65

Table-4 Electrical Properties Analysis

Upper Mezardere Development Plan

Teslimkoy Horizontal Producer

PUD location (9 wells)

P2U location (10 wells)

P3U locateon (14 wells)

BASE MAP - TEKIRDAG AREA

Teslimkoy Development Plan

TDR-5H1 L. Teslimkoy–Trajectory

BTD-4H DETERMINATION OF FLOW PERIOD

BTD-4H Square Root Time Plot

BTD-4H UNCONVENTIONAL ANALYSIS

60 acres of drainage area has been calculated from 11 months of production period

BTD-4H (Harmony) RTA analyses

BTD-5H UNCONVENTIONAL ANALYSIS

58 acres of drainage area has been calculated from 9 months of production period

BTD-5H (Harmony) RTA analyses

TYPE CURVE (P50) – TESLIMKOY HORIZONTAL

Teslimkoy Horizontal Type Curve

Teslimkoy zone frac – existing vertical well WO

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RESULTS

• Sandstones <1.6 md permeability will not flow gas but Upper Mezardere Siltstone as well as the Teslimkoy & Upper Kesan Sandstones have been successfully developed in Thrace Basin resulting in 7 BCF net (17 BCF GROSS) or 56% increase in Proved reserves from YE 2012 to YE 2013.

• 3D seismic data and existing well logs used to map structure and stratigraphy in tight gas reservoirs. Based on well completions in these tight sandstone reservoirs, the economic success obtained in the Teslimkoy formation was identified as the most prospective of the three.

• The Hydrocarbon bearing zones were found within the tight sandstone reservoirs in NW –SE trending accumulations associated with faults which provided for one of the four way closures within the three reservoir levels identified in bullet 2 above (i.e., Upper Mezardere, Teslimkoy and Kesan) and all accumulations encountered to date have similar structural trend and parallel closure geometry. Faults have high dip angle (>75°) with 100 to 25 m displacement and generally trend to NW.

• Structurally high parts of the study area show better EURs and lower water production after hydraulic fracturing completions. Water production after completions is mostly related with uncontrolled frac height reaching water bearing zones above and/or below target

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• Analyzed Teslimkoy Formation samples identify the sandstones as moderately and well sorted feldspathic litharenite. Bulk XRD results indicate quartz is the principal mineral in all samples, forming 52.2% to 72.9% of the bulk fractions.

• Total clay minerals comprise 5.3% to 9.1% of the bulk vol. Chlorite is the most common clay detected in all samples, forming 3.1% to 5.4% of the bulk vol. Smectite is indicated in all samples (<1%) but causes no significant formation damage problems by swelling if proper precautions (KCl added) during treatment operations in Teslimkoy Formation.

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• The overburden porosity and air permeability of the samples (at 1700 psi net confining pressure) range from 2.1% to 13.6% and 1.40x10-3 md to 0.858 md, respectively. The presence of Calcite and ferroan calcite and minor volumes of dolomite and ferroan dolomite cements in Teslimkoy sandstone reservoirs can significantly lower effective porosity.

• Values of m & n were determined from core analyses and used in Modified Simandoux shaley sand water saturation calculations to calculate water saturations. Empirical and core data supported a water saturation cutoff of 60% and qualification for candidacy for fracture stimulation. If gas zones were sufficiently distant from adjoining water bearing zones, zones were fracture stimulated.

• The water saturation and (cross plot) porosity values were used to establish parameters for volumetric IGIP and subsequent reserves calculations, augmented by area determinations from Harmony, RTA and pressure transient analyses (principally pressure buildup tests).