Integrated Geologic Study For Complex Fractured Carbonate Heavy Oil Reservoir

As an important part of Field Study and Development Plan for Tishrine Oilfield, which is located in the northern margin of the Arabian plate and northeast Syria, the objective of this dissertation is to provide an solid foundation for further understanding of fractured carbonate reservoir geology, building geologic model, preparing filed development and adjustment plan, exploration and appraisal based on carrying out the integrated geologic study related to the origin and distribution of complex fractured carbonate reservoir in Eocene Jaddla and Oligocene Chilolu formation.Based on the geological, geophysical, reservoir, production, and engineering data, taking the tectonic-sedimentation response process and the origin and distribution characteristics of the reservoir during the process as leading clue, this paper studied the stratum , tectonic movements, structure styles, sedimentary paleogeography, the origin and distribution of matrix porous reservoir and fractures, reservoir style and its main controlling factors. The major new understandings and achievements are as follows.1.Two episodic uplifts, a local NE-SW trending structure high on the uplift which have an important influence on the Jaddala～Chilou deposition occurred during early inversion, the NE-SW trending strike-slip faults formed during Jaddala C-Chilou B3 deposition and controlled by Palmyride fold and thrust belt in southwest Syria, and two fractured zones controlled by the strike-slip faults were identified. Based on the Statistical analysis of a large number of FMI, normal logs, seismic attributes and production data, it is concluded that the near N-S strike fractures which have great contribution to oil production were controlled by the strike-slip faults in the deep formations.2. It is pointed out that the paleo-topography during Jaddala～Chilou B2c deposition characterized as local small uplift in depression, and the sedimentary environment was deep basin rather than carbonate ramp and then gradually transformed into restricted platform isolated by surrounding fold mountains and structure highs. Overall, depositional environment determined that matrix porosity reservoirs in Jaddala-Chilou formation are undeveloped. Several very limited and local sets of thin layer porous reservoirs were altered by meteoric water leaching and were not the results of sedimentation. The exploration and evaluation in Sinjar area should be mainly focused on finding fractured reservoirs.3. The degree of Near NS fracture development caused by the NE-SW trending strike-slip faults in the deep formation and the sealing of the upper cap rock are the two most important controlling factors for Jaddala-Chilou reservoir in Tishrine oilfield. And the Chilou A reservoir is hydrodynamic composite oil reservoir with inverted oil-water relationship. Based on the integrated geologic study, two exploration and evaluation target area were predicted.