Fracture characterization is vital for efficient field development of naturally fractured Carbonate reservoirs. Successful development of fracture reservoir in the study area was possible due to early recognition of fracture play right from the exploration phase and through careful execution of relevant data acquisition campaign in the initial stages of field development. Comprehensive and integrated studies have been carried out over the past few years to arrive at an understanding of the conceptual model in deciphering structural evolution of North Kuwait Jurassic.Extensive core and image log data was acquired in the initial stages of field appraisal, which helped in comprehensive forward planning in design of deviated and horizontal wells. The data analysis steps included accurate and reliable reorientation of the cores. These data were calibrated with the image logs, along with available seismic attributes, which resulted in better understanding of structural evolution and sweet spotting of horizontal wells. This reorientation of the core data also helped in establishing a number of quantitative fractures attributes such as frequency, spacing, dip-azimuth and aperture along with mapping of in-situ stress directions. The detailed integration of these data also helped in accurately mapping the local and regional present day stress and its variations spatially across the fields. Stress direction across the field was helpful for deciding the azimuth of wells during well planning along with selection of completion strategy for current set of horizontal drilling Campaign.Drilling and testing results have been encouraging through enhanced reservoir performance in these tight carbonate reservoirs, based on these integrated studies.

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Deep, tight carbonate reservoirs of Pliensbachian, Sinemurian, and Hettangian Stages of the mid-Mesozoic Era are becoming very important in the continued pursuit of hydrocarbon prospects in North Kuwait. At present, a total of 21 wells have penetrated the targeted reservoir zones. Of these, 12 have been tested for hydrocarbon production covering a large area of about 1700 sq km. Further, six wells have produced oil and gas, with two deemed commercially successful. The entire workflow to characterize these reservoirs is focused on delineating faults and associated fractures in individual wells. Detailed seismic study and volume curvature maps, revealed the existing fault and fracture corridors. Sub-seismic faults and subtle reverse faults with fractures were detected by log correlations and borehole image. Due to paucity of cores in these zones, descriptions of cuttings samples were used to identify faults and fracture zones, based on the presence of large euhedral crystals in the midst of cryptocrystalline dolomite, suggesting the percolation of hydrothermal fluids through fractures. Many of the wells were drilled with an overbalanced mud system, leading to near-borehole porosity and permeability damage to the rock matrix and to the fracture system. Damage to natural fractures intersecting the well can prevent their detection, leading to missed potentially productive intervals. Mobility of hydrocarbons in these tight, fractured carbonate reservoirs depends upon (i) wells intersecting a natural fracture system that is sufficiently permeable and connected to a large volume of reservoir rock and (ii) the near-borehole area not having suffered irreversible damage due to overbalanced drilling. In summary, the proposed reservoirs are very tight carbonates (average 3 pu porosities) and a fracture play is considered to be the key factor in production. Acid stimulation produced multifold increases in productivity. Most of the wells were drilled overbalanced, which has negative impact on the producibility due to formation damage.

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