Research On Re-fracturing Technique In Zhongshanchuan Oilfield

Zhongshanchuan Oilfield is located in is located in the eastern Shanbei slope of ordos basin block, The existing exploring area of 392.5 square kilometers, the main reservoir of Triassic is Yanchang formation, the main characteristics of the reservoir is oil-bearing sand bed (Chang 2 and Chang4+5 and 6) covers a large area, oil-bearing shallow, low overburden pressure, lithology changes, poor physical property is one of the typical low permeability super low permeability reservoir. The oilfield fracturing renovation work began in the 90s of the 20th century, with the production time, the productivity of single well gradually reduced, by repeated fracturing to increase capacity demand upward trend, therefore repeated hydraulic fracturing technology transformation in the region has a broad application prospect, for long-term and effective use of low permeability reservoir is very important.The paper analyzes the basic geology of Zhongshanchuan Oilfield at first. After that focuses on the analysis of the characteristics of the reservoir, and then confirm the feasibility of re-fracturing in the block. Based on this, the paper focuses on the effects of reservoir rock elastic parameters, reservoir stress distribution, pore pressure and fluid viscosity on the repeated fracturing, and thus gives the repeated fracturing selection criteria and the construction process of different repeated fracturing. Secondly, the key technology of the repeated fracturing process technology, such as the selection of fracturing wells, the calculation of the stress of repeated fracturing, and the regularity of the fracture of repeated fracturingare analyzed. The research results show that the re-fracturing initiation and extension affected by initial fractures induced stress, fracture extension after equal stress points such as determined by the original ground stress.At last, the paper through the scene two re-fracturing wells construction data validate the paper theory method, confirmed the correctness of the theory and method in this paper, for the region repeated fracturing technology to provide a basis for the popularization and application.