Study On Optimization Design Method Of Horizontal Wells Pattern With Low Permeability

Most of the reservoir in Putaohua oil layer in the peripheral oilfields of Daqing with low permeability is low reserve abundance. The thin oil layer also has the characters of complex distribution, poor physical properties of crude oil, limited natural energy, poor stable status, and fast production decline , and the majority of wells in the lower natural production capacity. As a result, the research on reasonable and efficient development methods of low-permeability oil fields is needed.In this paper, based on the study of developing low permeability well pattern disposition with the application of horizontal wells in domestic and abroad, combined with geological characteristics in Daqing Oilfield Putaohua layer and the dynamic information of horizontal wells in development block which have been put into operation, the peripheral oilfields of Daqing with low permeability reservoirs is analyzed, the result of analysis is that the manner of vertical wells & horizontal wells is suitable for the peripheral oilfields of Daqing with low permeability reservoirs, while the horizontal wells' main impact factor is the appropriate-matching between well network deployment and cracks in the system. By studying 57 states Zhaozhou oilfield blocks with low-permeability reservoir , taking non-Darcy seepage theory as a guide, three-dimensional geological model by Petrel software is set up. Using reservoir simulation and reservoir engineering calculations, a set of optimization design methodology of deployment of vertical wells & horizontal wells suitable for Daqing low-permeability reservoir is proposed. Making a comprehensive measure through considering a combination of the relationship of well array direction & fracture parameters, horizontal segment length and network, predicted single well production, water content, the degree of recovery, as well as the prediction of the payback period and net present value, the methodology is obtained which is the mostly suitable for the development of the pattern form, well row direction, horizontal segment of the length in Putaohua layer of the peripheral oilfields of Daqing with low permeability reservoirs. The application shows that the state block has drilled 57 horizontal wells and 17 of which has put into operation, the current development of the initial single-well water yield 10.6 t / d, which is 4.3 times as that of a vertical well, the effect is good. The research is of important significance for improving the low-permeability reservoir of unused reserves.