-
Pressure Analysis Of A Well With An Inclined Hydraulic Fracture In A Naturally Fractured Reservoir
CHAPTER ONE -- [Total Page(s) 2]
Page 2 of 2
-
-
-
1.2 Technical Objectives:
· To provide background to justify
the conclusion that the direction of least principal stress might be at
an orientation different from parallel or perpendicular to the bedding
plane of the formation.
· To develop a technique, based on
the pressure derivative concept, for interpreting pressure transient
tests in wells with an inclined hydraulic fracture in naturally
fractured reservoirs.
Three cases are possible:
(a) The fracture is symmetric in both lateral and horizontal directions,
(b) The fracture is asymmetric in only one of the directions, and
(c) The fracture is asymmetric in both directions.
1.3 Hydraulically fractured wells
Naturally
fractured reservoirs are different from conventional (unfractured)
reservoirs. They are heterogeneous in type and consist of matrix blocks
separated from one another by the fracture system. The matrix blocks are
made of the original rock that was present before fracturing took
place. The matrix is characterized by its permeability km and porosity
φm . The fracture system is characterized by its permeability kfand
porosity φ f . It means a naturally fractured reservoir is a
double-porosity and double-permeability reservoir.
1.4 Naturally Fractured Reservoirs
Fractures
are displacement discontinuities in rocks, which appear as local breaks
in the natural sequence of the rock’s properties.It may appear as
micro-fissures with an extension of only several micrometers, or as
continental fractures with an extension of several thousand kilometres.
In
geological terms, a fracture is any planar or curvi-planar
discontinuity that has formed as a result of a process of brittle
deformation in the earth’s crust.Naturally fractured rocks can be
geologically categorized into three main types, based on their porosity
systems:
(1) Intercrystalline-intergranular;
(2) Fracture-matrix ; and
(3) Vugular-solution
CHAPTER ONE -- [Total Page(s) 2]
Page 2 of 2
-
-
ABSRACT - [ Total Page(s): 1 ]Hydraulic fracturing has been an effective technique to stimulate damaged wells or wells producing from low-permeability formation. It has been established that the orientation of a hydraulic fracture is perpendicular to the direction of the least principal stress in the formation. Thus, most pressure transient analysis techniques are based on the assumption that the fracture is vertical. However, it is now generally agreed that the direction of the least principal stress is not always parallel ... Continue reading---
