Storage and Seepage Unit: A New Approach to Evaluating Reservoir Anisotropy of Low-Permeability Sandstones

Abstract

According to geological characteristics of storage and seepage in the lowpermeability sandstone reservoirs, the storage and seepage unit is put forward to evaluate reservoir anisotropy of low-permeability sandstones in the paper. The storage and seepage unit is a special rock combination unit formed by sedimentation, diagenesis and tectogenesis. Then, starting with synthetical analysis of sedimentation, diagenesis and tectonic movement and based on plotting out storage unit of matrix pore and seepage unit of fracture, the storage and seepage unit can be obtained using the method of clustering analysis. Due to the differences of geological characteristics, fracture, micro-pore texture, micro-seepage mechanism and fluid interaction between fractures and pores, the enrichment rule for hydrocarbon and seepage rule for fluid are obviously different in the dissimilar types of the storage and seepage unit. The storage and seepage unit is the basic unit for development of the low-permeability sandstone reservoirs. It has important roles on compartmentalizing reservoir, predicting reservoir distribution and capability and guiding prediction of residual oil distribution.

Analysis of Hydraulic Fracture Morphology and Propagation under Different Perforation Azimuth Angles

“…Therefore, the primary problem for the efficient development of Fuyu reservoir is to establish a set of matching well completion technology according to the geological properties of the block, improve the seepage capacity of the reservoir, and guide the subsequent development of Fuyu block [5][6][7][8]. Due to the small scale of field test in the development of Fuyu reservoir, the immaturity of well pattern deployment in the well area, and the limitation of geological understanding and technological conditions at that time, there is a lack of guidance for the completion development of Fuyu reservoir under the current well pattern condition [9][10][11][12]. This study is mainly aimed at exploring the matching well completion technology of Fuyu reservoir under the condition of current well pattern and completion technology.…”

New inspiration on effective development of tight reservoir in secondary exploitation by using rock mechanics method

“…Zhang et al (2002) pointed out that the relationship between effective confining pressure and Young's modulus, compressive strength, is exponential through the core measurement but did not construct continuous changing model of mechanics properties in the process of water flooding; You (2003) believed that law of Young's modulus changing with the confining pressure reflects the rock internal damage state by measuring the cores with different lithology, and he thought that average Young's modulus value will be accurate relatively when considering the heterogeneity of the rock at the same time; Zeng et al (2012) put forward the storage and seepage unit which consists of sedimentation, diagenesis, and tectogenesis by using the method of clustering analysis to evaluate reservoir anisotropy of low-permeability sandstones. Yu and Tian (2013) calculated the anisotropic coefficient when rock mass mechanics parameters changed with confining pressure and predicted the relationship between the elastic modulus and depth; Adebayo and Adetula (2013) determined the hardness, brittleness, Rock Abrasivity Index (RAI), penetration rate, and bit wear rate to study the condition of drilling categorization.…”