Research and Practice of SRV Fracturing Technology for Inter-salt Shale Oil

doi:10.3969/j.issn.1006-6535.2022.02.022

Abstract

Abstract: The inter-salt shale oil reservoirs are characterized by unclear creep characteristics of the upper and lower salt rocks, susceptibility to interference with the upper and lower plastic rocks during fracturing, multiple lithological components, complex sensitivity, poor pore connectivity, and unclear dissolution pattern of soluble salts. There are more stringent requirements for SRV fracturing due to reservoir characteristics. For efficient development of inter-salt shale oil, Well BYY1HF in Paleogene inter-salt shale oil reservoir, Qianjiang Sag was tested with such technologies as CO₂ enhanced composite fracturing, acid-resistant fracturing fluid plus sanding, dense cutting plus forced-sanding fracturing, and temporary plugging fracturing with ball casting. CO₂ enhanced composite fracturing had the advantages of increased flowback capacity, improved matrix porosity and permeability, strong penetration, and high flowback rate. The acid-resistant fracturing fluid system could maintain stable performance, strong sand carrying capacity and low damage to reservoirs in acidic environment (pH 2-6). The dense cutting plus forced-sanding fracturing technology could eliminate the "agglomeration effect", promote the uniform opening and propagation of each cluster of fractures, and improve the SRV fracturing effect. The construction results showed that the technical system was advantaged by enhancing the flowback capacity, improving the porosity and permeability of the reservoir, promoting the rock capacity of fracturing initiation, fracture complexity, etc., and improving the oil supply capacity of the matrix to a certain extent. The test of fracturing technology is of great significance in reference for the large-scale fracturing transformation of inter-salt shale oil.

Key words: inter-salt shale oil, acid-resistant fracturing fluid, CO₂ complex SRV fracturing, dense cutting, temporary plug steering, Qianjiang Sag

CLC Number:

TE357.2

Liu Honglei, Xu Shengqiang, Zhu Biwei, Zhou Linbo, Huang Yajie, Li Baolin. Research and Practice of SRV Fracturing Technology for Inter-salt Shale Oil[J]. Special Oil & Gas Reservoirs, 2022, 29(2): 149-156.

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