Study On Comprehensive Interpretation Method Of Earth Stress In Different Tracts In Hailaer Oilfield

Oil gas field exploration and development acquire more and more researches on earth stress. The stress differential between pay zone and the upper and lower barriers is small in glutenite reservoir and budate reservoir with heterogeneous natural fracture system in hailaer oil field, and only 2-3 MPa, so far as to be unsheltered. These wells account for 73 percent of the fractured wells. Fracture height quickly propagates and effective propped fracture width decreases because stress contrast is small. With prop pant concentration increasing and fracture width gradually decreasing, sand plug immediately turns up when they reach the critical points. When some wells are perforated in the high stress position, fractures maybe turn to low stress position after opening, so there is friction near well bore, it is easy to cause sand plug. Alternately, small stress contrast between pay zone and barriers makes it easy to erratically fracture other beds in the course of building. Aimed at above problems we study the stress of different tracts in hailaer oilfield, we can clearly know the characteristic of earth stress, the stress contrast between pay zone and barriers, which can direct the establishment of fracturing and perforating program, avoiding that some wells are preformatted in high stress position, improving forecast level and fracture returns ratio.Geologic, geophysical exploration, well drilling, production, water flooding, fracture data supply abundant information for the study of earth stress, which are mot well used at present. In this paper, the earth stress distribution and influenced factors in hailaer field are analyzed, the present situation and rend of research technology of earth stress is fully researched, preexisting stress calculation models are comprehensively studied, the stress calculation soft ware is designed applying layering stress calculation model. The parameters required for earth stress calculation are determined, such as the rock mechanics parameters using log data and available results. The stress profile spreading data along the depth, columnar section and individual layer data etc. are obtained. Vertical and planar distribution rules of earth stress are gained by handling with computational solution in hailaer oilfield. Furthermore, computational solution is examined with stress data that is gained by means of hydraulic fracturing method. At the same time, the horizontal stress direction of the target zone in hailaer field is determined by means of borehole breakout data. Using log data to analyze earth stress is not only to quickly get the stress profile spreading along the depth, but also to save high cost for measurement, and it has large economic sense and pragmatic value.