Quantitative Identification And Cause Analysis Of Typical Fault Broken Zones In Dongxin Oilfield

A fault broken zone is defined as a complex three-dimensional geological body whichis composed of induced fractures and section fillings. It is mainly identified in the fieldoutcrop, while how to identify underground is still a problem. People haven’t known toomuch about the formation and cause of fault broken zone, and can’t set up right geologicalmodel of reservoir. So it is difficult to have further study in oilfield.Based on the observation of fault outcrop, and using comprehensive logginginformation and geological data, on the basis of different characteristics between well, thisarticle established well-between difference coefficient calculation formula and realized theautomatic identification of the fault broken zone in Yong-3fault block. Using the curvechanging rate method, fracture development coefficient, and the wavelet transform dividedthe internal structure of the fault broken zone. For the induce fracture, the curve changingrate is greater than0.05, the fracture development coefficient is greater than0.35, and afterwavelet transform, the acoustic show high-frequency and the resistivity showlow-frequency. For the section fillings in the cross section, the curve changing rate is lessthan0.05, the fracture development coefficient is less than0.35, but after wavelettransform, the acoustic and resistivity didn’t show the above-mentioned features. Throughwell-between difference coefficient and fracture development coefficient, this articleidentified the fault broken zone in the Xin-1fault block effectively. The study areadeveloped five types of fault broken zone: section filling fault broken zone, inducedfractures fault broken zone, asymmetrical-structure fault broken zone,symmetrical-structure fault broken zone, and complex-structure fault broken zone whichdon’t have regular induced fracture or section fillings.Evaluated the physical and sealing characteristics of different levels fault broken zonein Xin-1fault blocks, and found that the fault broken zone in the study area has goodsealing ability, and the section fillings is better than the induced fracture. According to theremaining oil data and the spatial distribution of the fault broken zone in Xin-1fault blocks,this paper studied the different structure of fault broken zone and the width of the section fillings’s influence on the degree of enrichment of remaining oil.Fault broken zone structure is influenced by many factors, this article studied faultoccurrence, fault activity intensity and so on, and how they effect the structure of the faultfracture zone.