Horizontal Permeability Anisotropy Characterization by Pressure Transient Testing and Geological Data

Summary The principal focus of this work is on pressure-transient analysis of a finite-conductivity inclined fracture connected to a slanted wellbore, on the basis of a semianalytical model. Detailed analysis of unsteady-state pressure behavior of a fully penetrating inclined fracture in an infinite-slab reservoir was provided. The study has shown that a finite-conductivity inclined fracture may exhibit five flow regimes: bilinear flow, formation linear flow, early radial flow, compound linear flow, and pseudoradial flow. The characteristics of bilinear flow and formation linear flow are predominantly determined by fracture conductivity. In the case of a low formation-thickness/fracture-half-length ratio and small inclination angle, both early radial flow and compound linear flow may be absent. Analytical solutions for transient responses during different flow regimes are similar to that for a fully penetrating vertical fracture and can be correlated with the cosine of fracture-inclination angle with consideration of permeability anisotropy. Effect of inclination angle and reservoir-permeability anisotropy on transient responses is strong, which extends to pseudoradial-flow period. Formation thickness mainly influences the middle to late flow periods. In addition, the pseudoskin factor is also investigated in detail.

Download Full-text

Horizontal Permeability Anisotropy Developed from the Upscaling of Anisotropic Facies Patterns: ABSTRACT

AAPG Bulletin ◽

10.1306/a25fe851-171b-11d7-8645000102c1865d ◽

1994 ◽

Vol 78 ◽

Author(s):

R. J. Norris, G. J. Massonnat, D. G

Keyword(s):

Permeability Anisotropy ◽

Horizontal Permeability

Download Full-text

Well-flow behavior of reorientation fracture considering permeability anisotropy

Engineering Computations ◽

10.1108/ec-12-2017-0516 ◽

2018 ◽

Vol 35 (7) ◽

pp. 2459-2479 ◽

Cited By ~ 1

Author(s):

Xiaoming Tian ◽

Pingchuan Dong

Keyword(s):

Hydraulic Fracturing ◽

Mathematical Models ◽

Flow Behavior ◽

Content Type ◽

Anisotropic Reservoir ◽

Infinite Conductivity ◽

Permeability Anisotropy ◽

Oil Productivity ◽

Horizontal Permeability ◽

Small Inclination

Purpose In petroleum industry, hydraulic fracturing is essential to enhance oil productivity. The hydraulic fractures are usually generated in the process of hydraulic fracturing. Although some mathematical models were proposed to analyze the well-flow behavior of conventional fracture, there are few models to depict unconventional fracture like reorientation fracture. To figure out the effect of reorientation fracture on production enhancement and guide the further on-site operating, this paper aims to investigate the well-flow behavior of vertical reorientation fracture in horizontal permeability anisotropic reservoir. Design/methodology/approach Based on the governing equation considering horizontal permeability anisotropy, the mathematical models for reorientation fractures in infinite reservoir are developed by using the principle of superposition. Furthermore, a rectangular closed drainage area is also considered to investigate the well-flow behavior of reorientation fracture, and the mathematical models are developed by using Green’s and source functions. Findings Computational results indicate that the flux distribution of infinite conductivity fracture is uniform at very early times. After a period, it will stabilize eventually. High permeability anisotropy and small inclination angle of reorientation will cause significant end point effect in the infinite conductivity fracture. The reorientation fractures with small inclination angle in high anisotropic reservoir are capable of improving 1-1.5 times more oil productivity in total. Originality/value This paper develops the mathematical methods to study the well-flow behavior for unconventional fracture, especially for reorientation fracture. The results validate the production enhancement effect of reorientation fracture and identify the sensitive parameters of productivity.

Download Full-text