Research On Radial Drilling Technology For Remaining Oil In High Segment Of Fault Block Reservoir

The fault block reservoirs are generally characterized by many faults,and the fault blocks are very small,which result to the fault system is complex.The development of the reservoirs is difficult to form a large area of regular well pattern,especially in the high water stage.According to the typical unit statistics,during the high water period,if the remaining oil reserves in the high part account for 9.6% of the block reservoir reserves,this part of the reserves are about 140 million tons,which has the low degree of development and great potential.Radial drilling is a new technology developed in recent years.It is a technique of drilling a radially distributed one or more branched borehole in a radial direction in a vertical well using a high pressure water jet,It can increase the oil drainage area,reduce construction costs and reduce reservoir pollution.In view of the residual oil characteristics of the high part of the fault block reservoir,the radial drilling technology has certain adaptability to the residual oil in the high-level fault,and the residual oil in the complex fault,as well as the high part of the complex fault block which is out of control caused by the secondary enrichment.In this paper,the problem of the current application of this technology in the development of fault block reservoir is less used and the mechanism and the specific parameters are not yet clear is studied.Based on the study of the characteristics of fault block reservoir and radial drilling,the conceptual model was established by numerical simulation.The sensitivity analysis of influencing factors of radial drilling are mainly studied,which considered the common factors of medium and high permeability reservoirs as well as the characteristics of fault block reservoir and radial drilling,and the adaptability of radial drilling and fault block reservoir is clarified.For the different types of reservoirs,the calculation method of the production formula of the fault type block reservoir and the strip fault block reservoir is deduced by using the conformal transformation,the mirror reflection and the superposition principle of the potential.Finally,by optimizing the number of radial drilling,location and other parameters,for different types of reservoirs put forward a reasonable technical policy to determine the extraction rate and the timing of extraction.