Hanan Oilfield Cracking

AbstractBased on the description and measurement of the drilling core, the test of tracer, and the study of micro oil displacement by water in the fractures, we have studied macro- and micro-fractures in the Ha'nan Oilfield. We have described the types and characteristics of fractures, determined the direction of fractures, discussed the relationship between faults and fractures, and finally analyzed the influence of the faults, macro- and micro-fractures on the waterfloooding. The knowledge are presented as followed:① The macro- and micro-fractures of the Ha'nan Oilfield are well-developed, and the fracture density is controlled by structural position, lithology and rock thickness.② The conclusion has been showed by the test of tracer that fractures are developed in the near of faults and the angle between faults and fractures is mainly 30((60(. The fracture net composed of faults and fractures is the main reason of water channeling near the faults.③ The micro oil displacement by water experiment of fractures has indicated that the micro-fractures have a great effect on the waterflooding. In the areas with micro-fractures rich-developed, it is profitable decreasing the injection amount by periodical injection.④ The formation of macro- and micro-fractures and faults is the same, and they are different stages of cracking. NE faults with different scale are conjugate with NW ones, and the former more than the latter. The NW faults are fractures in the ground. The direction of the conjugate fractures is changed with the variety of the direction of faults.⑤ The injection wells should be arranged along the direction of fractures, and the producing wells in the two sides. At the same time, the distance between injection wells should be lengthened suitably. It is profitable decreasing the injection amount by periodical injection. The well distance should be shorted in the low porosity and permeability reservoir in the south of Ha'nan Oilfield.