Fracture Characteristics and the Main Control Factors of Reef-Shoal Reservoirs in Central Region of Amu Darya Right Bank Block

It is low-energy ramp reef-shoal carbonate reservoir of Middle–Upper Jurassic strata in central region of Amu Darya right bank. The matrix physical property is poor. Affected by multiphase tectonic movement, structural fractures are important reservoir space and seepage channel. The fracture dip angle is in an extensive range, and the low dip angle fractures are in the majority. Considering filling and aperture, the high dip angle fractures are more effective, and the cutoff dip angle of the effective fractures is 30°. Fractures are mainly controlled by tectonic stress field, mechanical stratigraphic unit, lithological/microfacies, and mechanical stratigraphic unit thickness. Mechanical stratigraphic units control the fractures initiation and termination. It is obviously different in different microfacies. The fracture intensity is the highest in bioherms, the followed is in biodetritus banks, and the lowest is in inter-reef-shoal. The mechanical stratigraphic unit thickness has an obvious effect on controlling the fracture intensity. The thicker the stratum is, the higher the fracture intensity is. Based on the control factors, the areas where fractures developed could be predicted which could guide the development scheme optimization and adjustment, and the efficient development for eastern field.