PETROLEUM EXPLORATION AND DEVELOPMENT
Volume 37, Issue 3, June 2010
Online English edition of the Chinese language journal
Cite this article as: PETROL. EXPLOR. DEVELOP., 2010, 37(3): 316–324.
RESEARCH PAPER
Concept, principle, model and significance of the fault
controlling hydrocarbon theory
Luo Qun*
Basin and Reservoir Research Center, China University of Petroleum, Beijing 102249, China
Abstract: Based on discussions about the tectonic background and the relationship between faulting and petroleum accumulation in
Chinese continental basins, this paper introduces the basic concepts, principles, scientific foundation, an exploration of fault controlling
hydrocarbon theory as well as the differences between fault controlling hydrocarbon theory and other viewpoints about fault controlling
petroleum. The geologic tectonic backgrounds of compression from three directions, continental facies basin, extension in east and compression in west, developed faults and frequent tectonic movement suggests that faulting is the main reason for various geological processes that influence petroleum generation, migration, accumulation and distribution in Chinese oil-bearing basins. The exploration concept based on fault controlling hydrocarbon theory is: take faults as the main control factor, find the faults of controlling hydrocarbon
such as faults of controlling source and faults of controlling trap as well as seal faults, analyze their petroleum migration and accumulation potential, evaluate trap properties and determine the exploration targets.
Key words:
faulting; petroleum accumulation; fault controlling hydrocarbon; theoretical system; concept and principle; significance
Introduction
The theory of fault controlling hydrocarbon, which is also
called ‘theory of fault-controlling petroleum’, is a theoretical
knowledge system about the regular action of faults on the
generation, migration, accumulation, dispersion and distribution of hydrocarbons (including organic and inorganic hydrocarbons).
1 Concept of the fault controlling hydrocarbon
theory
1.1 Basic characteristics of the faulting action and
petroleum migration and accumulation of continental
basins in China
The Chinese mainland is situated at the junction of the
Eurasian plate, the Indian plate and the Pacific plate. A collision of the Eurasian plate against the Indian plate led to the
subduction of the Pacific plate beneath the Eurasian plate.
This particular tectonic position and state of stress have influenced the control of the faults in the Miocene and Cenozoic
era in China resulting in the formation of basins and petroleum generation, migration, accumulation, preservation and
distribution.
1.1.1 Tectonic behaviour of the Pacific and Eurasian
plates and its impact on the faulted basins on the Chinese
mainland and petroleum accumulation
The most fundamental characteristic of the Pacific and
Eurasian plates is the formation of a plate underthrust, namely
the underthrust of the Pacific plate beneath the latter[1–3]. The
movement of the Pacific plate produced an intense effect on
the Chinese mainland. It was so intensely compressed that a
multitude of reverse faults were formed and material in the
upper mantle beneath the continent moved upward and a horizontal tensile stress was generated in the crust. This lead to
the formation of both extensional and transtensional faults
with characteristics stated below: (1) faults with NNE and NE
strikes are dominant, cutting more than once through the
Paleogene structural units that can be new faults or a combination or extension of old ones. Of such faults the biggest are
the Tanlu fault and the Changzhi-Nenjiang fault, both of
which can extend as far as over one thousand kilometers. The
rest of the major faults can extend over 200–300 km and
longer while secondary faults are numerous. (2) Faults generated at different stages of the Miocene and Cenozoic era experienced changes in properties, as they were compressive at
the early stage of development, then extensional and tenso-
Received date: 24 Feb. 2008; Revised date: 24 Feb. 2010.
* Corresponding author. E-mail: luoqun2002@263.net
Foundation item: Foundation item: State ‘973’ project as part of the State basic research entitled ‘Hydrocarbon accumulation mechanism and distribution law of
typical superposed basins in west China’ (2006CB202306); Funded by the State’s important program entitled ‘key techniques for geophysical exploration in basins on
the continental margins’ (2008ZX05000-030-004).
Copyright © 2010, Research Institute of Petroleum Exploration and Development, PetroChina. Published by Elsevier BV. All rights reserved.
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
compressional. The Danlu fault demonstrates these characteristics[2,3]. (3) These faults have an intimate relationship with
petroleum accumulation, control the formation and evolution
of basins, decide the distribution of source rocks, form the
pathways for petroleum migration, restrict the occurrence of
traps and eventually lay control over the formation, preservation and distribution of petroleum reservoirs. Petroliferous
basins like the Songliao Basin, the Bohai Bay Basin, the
Jianghan Basin and the Beibu Bay Basin for example, and
thousands of petroleum reservoirs within them, were all
formed during the development of the Tanlu fault and the
Changzhi-Nenjiang fault. They formed as a result of the Pacific plate underthrusting the Eurasian (Chinese) plate to induce the movement of faults on different scales.
1.1.2 Tectonic behaviour of the Indian and Eurasian
plates and its effect on the movement of faults on the
Chinese mainland and petroleum accumulation
The collision of the Indian plate against the Eurasian plate
was a very complex process. The extrusion and collision of
these two plates as well as the significant impacts they produced in the Miocene and Cenozoic era are an accepted fact
worldwide[2,3]. The intense longitudinal extrusion in the
SSW—NNE direction gave rise to a series of giant faults and
different kinds of compressional basins and structural belts
under their control, consequently forming a tectonic framework characteristic alternately of intermountain and inland
basins in a NWW orientation in the vast areas of West China.
Between them lie faults usually as boundaries. On the margins
of the Qaidam Basin, for instance, they appear as thrust faults.
This basin developed folds and thrust faults with a NWW
strike. Basins formed upon such a tectonic background are
different from each other in their history of development. For
instance, the Junggar Basin was formed in the Late Permian,
while the Qaidam Basin formed in the Jurassic and the Tarim
Basin did not develop as a basin until the Paleocene, though it
received deposits only on its margins in the Cenozoic. However, their basic characteristics are similar in terms of hydrocarbon accumulation, that is, all of them are controlled by
reverse faults. Faults of the second and third levels within
these basins control the distribution of source rocks; the majority of traps spread along faults of different levels; faults are
the principal pathways for vertical hydrocarbon migration —
petroleum migration and accumulation occur where faults are
present. Most of the petroleum reservoirs discovered so far are
distributed along or nearby the faults; late-stage faulting is
important for preservation of petroleum.
To sum up, the particular geologic structural setting of
China demonstrates the fact that fault-controlled basins, faultcontrolled hydrocarbons and fault-controlled reservoirs are the
basic characteristics of the continental basins in the Cenozoic
and Neozoic.
1.2 Basic characteristic of faulting and its effect on
petroleum accumulation within continental basins in China
Compared with other structural types, the position and ef-
fect of the faulting within China’s continental basins are more
prominent. Such characteristics as universality, periodicity,
order and sequence characteristics, particularity, inheritance,
disparity and stage of faulting show an inevitable link to the
formation, evolution and distribution of reservoirs.
1.2.1
Universality of faulting
During the protracted evolution of the earth, factors like
mantle convection, plate underthrust, variation of the speed of
the rotation angle, gravity, magmatic intrusion, volcanic eruption and so forth all might form tectonic stresses like extension, extrusion and wrench movement. When these stresses
exceeded the tension, extrusion and wrench in strength, faults
are formed. At different locations and depths of the crust,
faults of different properties and scales exist. The presence
and movement of faults inevitably provide boundary conditions and geologic foundations for the formation of basins, the
development of source rocks, the migration and accumulation
of hydrocarbons and the distribution of traps.
1.2.2
Periodicity of faulting
Faults as crushed zones and weakened belts of the crust are
where the stress is most concentrated and where it is released.
After it forms, a fault, along with the evolution of tectonic
movement and the variation of the geo-stress field, would
continue to produce fault activities along a crushed zone and
develop along with the cycle of the tectonic movement like
crustal opening and closure, and the fault movement would
also show periodic variations. The priority of faulting within a
basin is intimately related to the closure and opening of a fault,
which has a significant impact on the multi-period but longterm and periodic migration and accumulation of hydrocarbons and the destruction of reservoirs.
1.2.3
Order and sequence characteristics of faulting
The order and sequence characteristics of faulting means
that the control of faulting over sedimentation and structures
is in order, while sedimentation and structures are the most
fundamental factors for petroleum generation and accumulation. Therefore, the scale and property of a reservoir are
closely related to the order and sequence characteristics of
faulting.
1.2.4
Characteristics of faulting
The material components that form the crust, the disparity
of the geologic structure, the unevenness of stress fields and
differences in geologic conditions will inevitably cause differences in characteristics between faults and other geologic
structures like folds, joints and fractures. This affects fault
development and characteristics which have a great influence
on petroleum migration and accumulation due to their control
and position.
1.2.5
Inheritance of faulting
Long-term inheritance and development are two important
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
characteristics of the deep basement faults in different types of
basins. Since faults are always present in a tectonically weakened zone and the stress produced in each tectonic movement
is always transmitted to and concentrated in the structurally
weak zone where it is then released, the movement of most
faults have a striking characteristic of inheritance. The inheritance and multi-period movement of faulting are favorable to
long-term and multi-stage migration and accumulation, thus
making it possible for the formation of hydrocarbon accumulation. The inheritance of faulting also provides conditions for
the formation of traps of a variety of origins along the crush
zone.
1.2.6
Stages of faulting
In different periods of regional tectonic evolution, the difference in regional stress fields and the manner and property
of tectonic movement causes faults to display different characteristics of movement at different stages. In the rifted basins
in East China, for instance, the basal faults present a characteristic of syn-sedimentary growth due to regional tension and
transtension; the tectonic movement in a period of depression
can be relatively peaceful, when the faults no longer move or
move on a small scale. Tectonic inversion at the late stage of
basin development has activated many a fault, which resumes
their movement or inversion or slipping. Different displays of
faulting at different periods have played different roles of
control over petroleum generation, migration, accumulation
and preservation and also determined the timing characteristic
of petroleum migration and accumulation.
1.2.7
Systematics of faulting
The systematics of fault development refers to different
forms, different orders and different sequences, but it has the
whole characteristic of a concerted evolution of faults linked
by origin. A fault combination formed under the same stress
field in the same period constitutes a fault system. In accordance with the stress characteristic and the characteristic of
fault development, faults are divided into three major categories including a tensional system, a compressive fault system
and torsional system. Each of them plays different roles in the
formation and evolution of petroleum reservoirs. The property
and characteristic of the fault systems restrict the forming,
properties and characteristics of a hydrocarbon accumulation
system.
1.3 The theory of fault controlling hydrocarbon
accumulations
1.3.1 Advancements in the study of fault controlling
hydrocarbon accumulations
The control of faults over the formation of basins and over
petroleum migration and accumulation aroused geologists’
attention long ago. In the 1950s Li Siguang proposed, ‘Structural surfaces of different mechanic properties have different
roles of control over hydrocarbons. The mechanical property
as well as transformation and imposition of a structural surface are of significance to petroleum control. A large tenso-compression fault often extends far and has a large depth
and serves as an important pathway for petroleum migration.
A compressional fault has a good enclosure property and
forms a screened oil reservoir. An extensional fault has an
opening property and petroleum often escapes along it, unfavorable to petroleum accumulation’[4]. In the 1960s, prior to
and after the great battle for petroleum in the Bohai Bay, experts at different oilfields and scholars advanced a series of
viewpoints and observations concerning faults controlling
petroleum distribution by conducting detailed in-depth studies
and reviews. Zhang Wenyou, for example, described the control of faults over petroleum, pointing out that “The Heiyupao-Gudian fault played a decisive role in the formation of the
Changhuan reservoir in Daqing” and that “special importance
should be attached to research on the formation and development of a basin under the control of a basal fault” and that
“When petroleum migrates and accumulates along the fracture
belt, petroleum within each faulted block can have different
characteristics and independent systems that become fault
block oilfields” [5]. Li Desheng, by making a systematic study
of the geologic structural characteristics and the distribution
of oil and gas fields in the Bohai Bay Basin in the 1980s,
conducted an in-depth analysis of the control of half-graben
faults over petroleum and of compound petroleum structures,
pointing out that “there are a total of fifty lower Tertiary depressions distributed along the major faults, each of which
might become an independent unit of petroleum enrichment
and its own petroleum-bearing system and oil-forming combination” [1]. Zhu Xia[6], Lu Kezheng[7] and Chen Yixian[8]
brought forward more systematically the understanding and
viewpoints concerning the control of faults over the formation
and distribution of petroleum reservoirs from different angles.
There were many other relevant articles and monographs[1–3,5,9–20] that discuss this to a high level. Although the
discussions of the control of faults over petroleum reservoirs
by the above experts and scholars are relatively in-depth and
systematic, all of them made summaries of some aspects regarding fault-controlling petroleum accumulations in some
regions or basins but failed to form a relatively independent
and complete system of theoretical knowledge.
1.3.2
Proposition of fault controlling hydrocarbon theory
Behind the six major petroleum controlling factors like
‘generation, storage, cap formation, migration, trapping and
preservation’ there must be a most fundamental, most important one as well that dominates and controls these six major factors.
In recent years, the scientific projects the authors have participated in and undertaken are in most cases about tectonic
research and petroleum reservoir evaluation and particular
attention has been paid to the special role that faults play in
the formation of basins and in hydrocarbon generation, dis-
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
charge, migration, accumulation and dissipation. Further research indicates that faults do not merely control the distribution of petroleum reservoirs but the latter are also closely related to the development and accumulation of oil-bearing
source rocks and the distribution of traps. By way of
re-establishing the development of faults and the generation,
migration, accumulation and dissipation processes of hydrocarbons, a comparison of these features both in time and space
shows that they have an obvious correlation in such aspects as
the extent of development, the synchronicity and the spatial
match, that the better they match in time and space, the more
abundant the hydrocarbon accumulation will be.
Based on an acquisition of sufficient examples of faults
controlling hydrocarbons generation, migration, accumulation,
dissipation and distribution, a fault controlling hydrocarbon
pattern of more extensive significance is brought forward.
Geotectonic theory and petroleum geologic theory are applied
in the search for a scientific basis for the support of faults
controlling hydrocarbons. These theories are built upon the
basis of previous research in combination with the characteristics of China’s continental oil-bearing basins and petroleum
reservoirs to give a theory of faults of controlling hydrocarbons. The theory assumes that “faults are the fundamental
cause for control over hydrocarbons generation, migration,
accumulation, preservation and distribution” and is approved
by experts like Li Desheng, Ma Zongjin, Hu Jianyi, Huang
Difan, Wang Xiepei, Liu Hepu, et al. (personal communication).
The ‘theory of faults controlling hydrocarbons’ takes its
roots from the special geotectonic background and geologic
structural style of China: compression from three sides, dominantly continental facies, extension in east and compression
in west, development of faults and frequent movements, these
characteristics have contributed to the special position of
faults dominating hydrocarbons formation, evolution and distribution and their irreplaceable role. Such characteristics decided the geologic setting, material basis and accumulation
conditions for the formation of petroliferous basins and petroleum reservoirs in parts of China.
Fig. 1
2 Theory of fault controlling hydrocarbons
2.1
Evidence of fault controlling hydrocarbons
(1) Both the formation and distribution of China’s petroliferous basins are controlled by major deep faults [1,21].
(2) Field investigations, drilling and geophysical prospecting indicate that almost all the hydrocarbons of an inorganic
origin discovered so far migrated upward from the deep underground through major deep faults[21–23].
(3) Explorations and statistics indicate that the majority of
the petroleum reservoirs in eastern China are controlled by
faults and that most reservoirs in central and western China
are also intimately linked to the faults there.
According to the statistics of five elements for hydrocarbon
accumulation, such as faults controlling origin, faults controlling migration, faults controlling traps, faults controlling accumulation and faults controlling distribution in forty typical
oil and gas reservoirs like the Saertu, Fuyu and Gudao reservoirs in eighteen oil-bearing basins across Songliao and the
Bohai Bay, all important control ratios (absolute control rate
plus apparent control ratio) are above 70%[24].
2.2 Basic concept of the theory of fault controlling
hydrocarbons
2.2.1
Faults of controlling hydrocarbons
The fault that lays important control over the generation,
migration, accumulation, dissipation and distribution of hydrocarbon compounds (petroleum) is called a fault with control over hydrocarbons. In accordance with the different aspects of a faults’ control over the generation, migration, accumulation, dissipation and distribution of hydrocarbons,
these faults are divided into eight basic types, namely faults
with control over the source, faults with control over migration from the source, faults with control over traps, faults as
barriers to hydrocarbon migration, faults changing the direction of hydrocarbon migration, faults destroying reservoirs,
faults readjusting reservoirs, and faults linking hydrocarbon
migration channels (Fig. 1).
Schematic drawing of fault controlling hydrocarbon patterns and the basic types of faults with control over hydrocarbons
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
(1) Fault of controlling source rock are those that play an
important role in controlling the formation, evolution, scale
and distribution of source rocks.
(2) Fault of controlling migration from the source refer to
those that connect source rocks and conduct the petroleum
discharged from mature source rocks to migrate out of the
source rock.
(3) Fault of controlling trap is one that has direct control
over the formation and distribution of traps. The traps under
its control can be tectonic traps or atectonic ones.
(4) Fault as barriers to hydrocarbon migration is one that
stop hydrocarbons from continued migration and act as a seal
for the reservoir. Faults of this type are usually barriers to
hydrocarbon migration. They have good confining properties.
(5) Fault of changing the direction of hydrocarbon migration is one that lie in the pathway of petroleum migration and
change the direction of petroleum migration. Faults of this
kind, open or closed, will change the direction of petroleum
migration all the same.
(6) Fault of destroying a reservoir is a fault that is destructive to petroleum reservoirs already formed. It might be a new
fault that incises a reservoir due to tectonic movement after
the reservoir’s formation, or a previously destructive fault
whose confining properties reduce, thus leading to a leakage
or loss of the petroleum in a reservoir.
(7) A fault readjusting the reservoir is a fault that destroys a
reservoir already formed and provides pathways of migration
resulting in the formation of a new reservoir. Faults of this
kind destroy existing reservoirs but at the same time supplies
petroleum for the formation of new reservoirs, leading to readjustment and redistribution of the petroleum in the former
reservoir.
(8) A fault that links hydrocarbon migration channels is one
that connects the pathways of migration, for example unconformities and (or) conducting layers, guiding the long-distance
and multi-route migration of petroleum through migration
pathways of different types and serving as a “bridge” over
different types of migration pathways.
The above descriptions are about eight basic types of faults
with control over hydrocarbon distribution. In effect, a fault
with control over hydrocarbons might have many an effect of
controlling hydrocarbons at the same period or different periods or different levels. For instance, a fault with control over
the source acts often as one with control over traps and oil
sources at the same time. A fault with control over the oil
source might be a fault as a barrier to hydrocarbon migration
for this trap but a fault changing the direction of hydrocarbon
migration for another and in turn become a destructive fault at
another period in time. Therefore, discussions of the types of
faults controlling hydrocarbons and their role must include the
specific fault, the specific trap and the specific period involved.
2.2.2
Faults with control over reservoirs
Faults of this type have direct control over the formation
and distribution of petroleum reservoirs, including faults with
control over traps, faults with control over the migration from
the source, faults as barriers to hydrocarbon migration and
destructive faults. Faults with control over reservoirs consist
of one type or several types of faults that control hydrocarbons.
2.2.3
Fault controlling elements
Fault controlling factors refer to fault-controlled geologic
factors (bodies) that are directly related to the pooling and
distribution of petroleum, including faults with control over
migration from the source, faults with control over the traps,
faults with control over the pathways, fault body traps, and so
on.
(1) Source rock controlled by fault refers to source rocks
whose formation, evolution and distribution are under the
direct control of faults.
(2) Trap controlled by fault refer to those (including
structural traps and atectonic ones) whose formation, evolution and distribution are under the direct control of faults.
(3) Pathways controlled by fault refer to the pathways of
petroleum migration directly under the control of faults, including faults controlling migration from the oil source and
crush zones (or fracture network systems), with good conductivity but subject to faulting.
(4) Strength migration pathway in a fault refer to the space
within a fault where the maximum fluid potential drop is
formed.
(5) Fault body traps and fault body reservoirs: A fault body
trap, as a special fault-controlling trap, is a fault body (made
up of broken fault belts) endowed with conducting and reservoir properties, and has a relatively low potential area due to
barriers or sealing on all sides and at top (shale, salt rock,
asphaltic rock and other tight formations). A fault body trap
will be formed when it is supplied with hydrocarbons.
(6) Reservoir controlled by fault is referred to as reservoir
whose formation, evolution and distribution are all controlled
by faults.
2.3 Basic principle of the theory of fault controlling
hydrocarbons
2.3.1
Geologic principle
The basic principle of the ‘fault controlling hydrocarbon
theory’ includes: All different formations of a lithosphere are
composed of masses confined by faulted blocks of different
sizes, shapes, properties and ages[5]; there is an inseparable
intimate relationship between major deep faults that cut
through the lithosphere, the crust and the upper crust, and
sedimentary basins; the history of the Earth’s development is
a cycle of the complex but alternate opening and closure of
the lithosphere[10]; the movement of matters in the deep mantle leads to the opening of the crust. As a result, major deep
faults occur and rifted sedimentary basins are formed. The
opening and closure cause the collision or subduction of faults,
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
and the orogeny arising also leads to the formation of compressional basins; the intense inheriting movement of faults in
the evolutionary process of a basin leads to the formation of
source rocks on deep regime facies tracts, favorable for the
preservation and transformation of organic matters; due to a
change of the movement system, the characteristic and property of the faults’ activities vary, leading to frequent water
transgression and regression and forming many sourcereservoir-cap assemblages; at the late stage of basin development, due to a drop of the geo-temperature, the contraction of
the crust and the horizontal extrusion of the plate, favorable
structural and non-structural traps like rollover anticlines,
reverse drag anticlines, compressional anticlines and faulted
noses, occur along the fault of earlier movement, providing
space for hydrocarbon accumulation; the fault connects the
source rocks and the traps or becomes a tie linking the unconformity surfaces to the conducting formation, forming a
pathway network system for hydrocarbon migration and promoting the migration and accumulation of hydrocarbons; the
late-stage fault movement leads to the destruction of reservoirs and the redistribution of hydrocarbons; major deep faults
control the forming and evolution of the main faults and all
the secondary ones, thus controlling and affecting the forming
and orderly distribution of the reservoirs of different scales
and types as well; the inheritance, level and discrepancy of the
fault development lead to the occurrence of various types of
reservoirs; fault control over hydrocarbons presents different
roles (advantageous or disadvantageous, direct or indirect,
macroscopic or microscopic) in terms of the variations of time,
space and geologic conditions.
In sum, faults are the fundamental causes controlling over
the generation, discharge, migration, accumulation, dissipation and distribution of hydrocarbons. The basic principle of
the fault-controlling hydrocarbon theory and the process of
fault controlling hydrocarbon can be summarized as Fig. 2.
Fig. 2 Principle of fault controlling hydrocarbon and the structural diagram
2.3.2
Mathematical principle
The principle of fault control over petroleum reservoirs can
be expressed figuratively using the following mathematic
relationship:
R = ∂F f(Xi)
(i=1, 2, …, 7)
(1)
where R—extent of hydrocarbons to be a reservoir, ∂F—factor
of fault controlling reservoir. When ∂F>1, fault movement is
helpful to the formation and preservation of a reservoir. When
∂F<1, it is unfavorable for the formation and preservation of a
reservoir. In usual cases, ∂F>1. Only when a reservoir is
formed, ∂F<1 in areas where the fault tectonic movement is
more intense. When the late-stage fault movement completely
destroys the reservoir, ∂F =0. ∂F =1 indicates that the fault has
no control over the forming and preservation of reservoir. X1,
X2, …, X7 respectively represent oil generating condition, reservoir condition, cap rock condition, migration condition,
trapping condition and preserving condition as well as the
relationships of these six factors in time and space, all of
which are the geologic factors affecting the extent R of hydrocarbons to be a reservoir.
Statistics show that in petroliferous areas where faults are
developed, the correlation coefficient of R and ∂F is 0.7 and
above.
The coefficient ∂F of fault controlling reservoir is restricted
jointly by the extents of a fault with control over the source, a
fault with control over migration from the source, a fault with
control over the traps and a destructive fault. It is a comprehensive index, namely.
∂F = f (a1, a2, a3, a4)
(2)
where a1, a2, a3 and a4 represent, respectively, the extent of a
fault controlling over the source, a fault controlling over migration, a fault controlling over the traps and a fault destroying the reservoir. For a specific fault, the extent of its control
over a reservoir is also related to such factors as the time (t),
the intensity (p) and the period and order (n) of fault movement as well as its spatial relationship (s1) with traps, its spatial relationship with the oil source (s2), its confining property
(m) and its scale (u), namely
∂F = f (t, p, n, s1, s2, m, u, …)
(3)
Therefore, comprehensive considerations ought to be given
to its control over hydrocarbon generation, migration, accumulation and dissipation when the control of a fault over the
reservoir is studied, that is, to make a comprehensive study of
the history of fault development and its matched relationship
to time and space as well as the history of hydrocarbon generation, migration, accumulation and dissipation and its
matched relationship to time an space, a study of the relationship of ∂F to ai (i=1,2,3,4) and a study of ∂F to such factors as t,
p, n, s1, s2, m and u so as to make a scientific analysis of the
characteristic of a fault of controlling the reservoir, to be really enabled to get what is wanted as a matter of course, and to
provide a scientific foundation for search of reservoirs related
to faults.
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
2.4 Principal viewpoints of the theory of fault controlling
over hydrocarbon
2.4.1
Pattern of fault controlling hydrocarbon
Fault controlling hydrocarbon is referred to as the law of
control of major deep faults and induced faults over reservoirs’ formation and distribution, including advantageous and
disadvantageous control, direct and indirect control, and
macroscopic and microscopic control, of which advantageous
control, direct control and macroscopic control are dominant.
The law of fault controlling hydrocarbon can be summarized as the pattern of fault controlling hydrocarbon and reservoir. Fig. 3 is the pattern of fault controlling hydrocarbon in
the Qaidam Basin, West China.
2.4.2 Fault controlling hydrocarbon is the basic
characteristic of China’s petroliferous basins
Exploration practice and statistics indicate that fault controlling hydrocarbon is the basic characteristic of petroliferous
basins in China. Fault controlling hydrocarbon includes the
control of faults over seven aspects: oil-bearing basins, source
rocks, hydrocarbon migration, reservoir conditions, trapping
conditions and hydrocarbon preserving conditions. The diversity of fault controlling hydrocarbon decides the complexity
of hydrocarbon accumulation. Different parts or the same part
of the same fault at different evolutionary stages have different roles of control in terms of different traps.
2.4.3 Fault control over reservoirs’ formation and
distribution is a systematic control system
Fault controlling hydrocarbon in China’s oil-bearing basins
presents eight basic characteristics: universality, dominance,
constancy, disparity, stage, sequence, order and system, all of
which are called the regularities of fault controlling hydrocarbon. Fault control over reservoir forming and distribution
is displayed in the control arising from the formation and
evolution of a fault system over hydrocarbon generation, migration, accumulation and dissipation and over the formation
Fig. 3
and evolution of reservoir-forming systems. A correct analysis
and understanding of the basic characteristic of a fault system
and its control over hydrocarbons to ascertain the distribution
law of petroleum reservoirs is a road that has to be taken for
scientific explorations.
2.4.4 Major deep faults and their movement are the
fundamental controlling factors for different geologic
effects of petroliferous basins and for reservoirs
formation and distribution.
The movement of major deep faults not only leads to the
formation of oil-bearing basins but at the same time is a
boundary condition and inductive factor for a variety of geologic activities like the tectonic evolution and sedimentary
development of basins and volcanic (magma) movement, thus
fundamentally deciding the generation, migration, accumulation, preservation and distribution of hydrocarbons. Major
deep faults and their movement are the fundamental controlling factor for different geologic effects within oil-bearing
basins and the forming of petroleum reservoirs (including
subtle reservoirs). This statement is the very basic viewpoint
of the theory of fault controlling hydrocarbon.
2.4.5 Zones (or belts) of fault development in the
petroliferous basins of China extremely possibly are
where petroleum is accumulated.
There is a great possibility that the zones (or belts) of fault
development in the petroliferous basins of China, especially
those that extend to the source rock areas, are petroleum-accumulated zones. Petroleum accumulation zones within
the superposed basins in both East and West China are in most
cases compound petroleum accumulation zones with faults as
the dominant controlling factor, where the reservoir scale is in
positive correlation with the scale of faults that control the
reservoirs there, and they spread along the main faults in the
shape of line, arc, ring, band and feather. The petroleum distribution there not only follows ‘the theory of source control’
an d ‘ th e th e o ry o f s t ru ct u re con t ro l li n g oi l’ bu t
Pattern of fault controlling hydrocarbons in the Qaidam Basin
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
also obeys the regularity of ‘fault controlling hydrocarbon’.
2.4.6 Major deep faults control the migration,
accumulation and distribution of inorganic hydrocarbons
Faults control the formation and distribution of hydrocarbons of organic origin, they are also the only pathway on
which inorganic hydrocarbons are synthesized and then migrate upward to the upper crust for accumulation. Areas containing both sedimentary and non-sedimentary source rocks
that are distributed along the major deep faults possibly are
those favorable for exploration of the hydrocarbons of inorganic origin.
2.5 Scientific basis for the theory of ‘fault controlling
hydrocarbon’
(1) A sedimentary basin is a basic geologic unit in which a
reservoir of organic origin is formed, while faults control the
formation and evolution of such a basin.
(2) The theory of natural gas of abiogenesis argues that in
the deep of the earth there exists a great amount of natural gas
(including hydrocarbon gas). Major deep faults provide both a
place for synthesis of hydrocarbons of inorganic origin and
the pathways for upward migration of the inorganic hydrocarbons to the surface layer of the crust for accumulation on
their way from the mantle or the deep of the crust into faults.
(3) Geotectonic theories like the ‘theory of plate tectonics’,
‘theory of faulted block structure’, ‘theory of trough platform’
and geologic mechanics, etc are all concerned with the characteristics of faults and the description and explanation of
basins (depressions) and the regularity of the faults’ control
over hydrocarbons, providing theoretical foundations for
‘fault controlling hydrocarbon.
2.6 Exploration philosophy based on the theory of fault
controlling hydrocarbon
The theory of fault controlling hydrocarbon believes that
faults are the fundamental factor that controls the varied geologic effects within petroliferous basins on the one hand and
hydrocarbon generation, migration, accumulation, dissipation
and distribution on the other. The relationship of faults and
reservoirs can be compared to that of branches and fruits or of
vines to melons. Therefore, the exploration philosophy based
on fault controlling hydrocarbon is to pick the fruits “along
the branches” (faults and the preferred migration pathways
under their control or connected with them) and “feel for the
melons (reservoirs) along the vines (faults)”, that is, to take
faults (major deep ones in particular) as the principal controlling factor and a basic clue in search of faults with control
over the source, faults with control over traps, faults with
control over migration from the source, faults as barriers to
hydrocarbon migration, etc in light of the general principle
and law of the petroleum geologic theory to analyze the hydrocarbon migration conditions for fault-controlled traps and
fault-related traps and to make an evaluation of petroliferous
property and to locate advantaged exploration targets. What is
Fig. 4 Technical route of exploration based on the theory of
fault controlling hydrocarbon
worth noticing is that not every branch has fruits on it, not all
vines having fruits on them. This requires an analysis of the
cause-effect relationship of the difference of fault controlling
hydrocarbon to hydrocarbon migration and accumulation, to
find advantaged ‘branches’ and ‘vines’. The technical procedure of exploration based on the theory of fault controlling
hydrocarbon is presented as Fig. 4.
3 Uniqueness of the theory of ‘fault controlling
hydrocarbon’
The theory of ‘fault controlling hydrocarbon’ has inherited
and developed our predecessors’ achievements in research on
fault controlling petroleum, but it is a more comprehensive,
more systematic and more deep-going revelation of the essence of fault controlling hydrocarbon. Compared with other
achievements, this theory displays several striking characteristics as follows:
(1) Strongly systematic. It brings forward the theoretical
and factual bases whereupon are formed a package of basic
scientific concepts, principles, viewpoints, foundations and
exploration philosophies as an integrated system of
knowledge.
(2) A broader coverage: In addition to hydrocarbons of organic origin, the theory of ‘fault controlling hydrocarbon’ is
aimed at hydrocarbons of inorganic origin. Besides structural
reservoirs, it is applied to quite a number of non-structural
reservoirs. Besides its application to China, it will as a matter
of course serve as an important guidance to the prediction of
petroleum explorations across the globe.
(3) The theory lays more stress on the dominant role of
faults and its intrinsic relations with hydrocarbon accumulation. The process of fault controlling hydrocarbon is itself an
integrated system of objective reality concerning hydrocarbon
reservoirs formation, evolution and distribution and takes
faults as the principal controlling factor. The theory of ‘fault
controlling hydrocarbon’ specifically points out that faults are
the fundamental factor controlling hydrocarbon generation,
migration, accumulation, preservation and distribution, lays
more stress on the organic integration of faults’ movement
with hydrocarbon generation, migration, accumulation, dissipation and distribution, and gains a full knowledge of the
proper relation of correspondence of fault development on the
one hand and hydrocarbon accumulation and dissipation in
time and space distribution on the other, and of an intrinsic
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
but inevitable connection of fault movement with the cause of
formation (or between cause and effect).
(4) It figuratively makes an exploration philosophy of
looking for oil by ‘seeking for the melons along the vines’.
In recent years, the theory of fault controlling hydrocarbon
has been applied to the exploration practice in the Songliao,
Bohai Bay, Qaidam, Beibuwan and Ordos basins with good
results[24,25], indicating that the theory is a scientific theoretic
system. Yet, as it was brought forward not long ago and is still
far from perfection, the theory needs a further development in
practice.
4 Significance of the theory of fault controlling
hydrocarbon
4.1
Theoretical significance
The theory of fault controlling hydrocarbon, by having a
tight grasp of the dominant geologic factors for hydrocarbon
generation, migration, accumulation, dissipation and distribution in continental basins, gives a full revelation of the mechanism and law of hydrocarbon migration and accumulation
and forms at the first step a theoretic system more predictive,
more complete and more integrated, thus enriching and improving the theory of petroleum exploration.
4.2
Practical significance
In addition to providing a scientific foundation and philosophy for a rapid but effective discovery of reservoirs, the theory of fault controlling hydrocarbon is of practical significance in the following aspects:
4.2.1 Theoretical basis for finding inorganic
hydrocarbons.
The theory of petroleum of organic origin considers that
oil-bearing areas are only within ‘basins’ and, as a consequence, the viewpoint ‘there is no oil without basins’ has taken
Fig. 5
roots in the mind of prospectors, while the theory of fault
controlling hydrocarbon believes that for hydrocarbons of
either organic or inorganic origin, so long as faults act as the
migration pathway, they can migrate along the fault to any
part of the crust, including to the outside of the basin, and
gather as a reservoir in any suitable trap around the fault. At
present, there is a phenomenon that much natural gas of inorganic origin has dissipated along major deep faults up to the
earth’s surface, which occurs not in all sedimentary basins.
There have developed many deep-cut major faults that extend
afar in China. They are connected with the giant underground
‘stock-house’ of hydrocarbons of inorganic origin. Therefore,
traps (within or outside sedimentary basins) distributed along
these major deep-cut faults (belts) ought to be important targets for exploration. Fig. 5 is the accumulation mode of hydrocarbons of inorganic origin in the mainland China. What
deserves attention is that petroleum of organic origin in basins
is limited and a considerable portion has been produced, while
the inorganic hydrocarbons deep underground are an infinite
amount. In search of ‘mantle source gas’ and ‘combustible
ice’ for instance, these major deep-cut faults and their vicinities will be realms of importance for exploration.
4.2.2 Look for oil in areas far from the oil source along
the fault by breaking through the constraints of ‘the theory
of source control’
The ‘theory of source control’ helped prospectors find a
good many reservoirs indeed in the source rock area and its
vicinity. Yet, it also might make us lose many an opportunity
to find petroleum reservoirs far from source rock areas. It is
true that in continental petroliferous basins, due to intense
facies change, it is difficult for hydrocarbons to migrate over a
long distance and they are distributed around the source rock
areas and the vicinity. But there is a possibility for hydrocarbons to migrate over long distances along a major fault and
Migration and accumulation pattern of inorganic hydrocarbons in the Chinese mainland
Luo Qun. / Petroleum Exploration and Development, 2010, 37(3): 316–324
gather as a reservoir in a trap in non-source rock areas or far
from the source rock areas, when hydrocarbons are enabled to
migrate upward along a fault in multi-period movement and
cumulate at multi-stages as a reservoir in the overlying formation, forming a superposed and connected mass of hydrocarbon assemblage. They also might migrate laterally along
the strike of a fault in multi-period movement and become a
multi-period reservoir outside or far from the source rock
areas, making a laterally superposed and connected mass of
hydrocarbon assemblage. It does exist that hydrocarbons migrate along the strike of a fault from the source rock areas to
non-source rock areas. The reservoir on the Wen’an slope area
in the Jizhong depression is such a case.
‘The earth is a processing factory of petroleum’ and ‘the
earth is a block of sponge that has absorbed enough petroleum’, these philosophical statements are not only a great encouragement to oil hunters but provide a more spacious realm
of thinking as well. If the earth is a ‘processing factory of
petroleum’, then the fault mentioned in the theory of fault
controlling hydrocarbon is ‘an oil transmission pipeline’ that
will deliver oil continuously to the earth’s surface. Then the
theory of fault controlling hydrocarbon will be a golden key to
the ‘storage park’ underground.
1995. 165–170.
[10] Guo Zhanqian, Xiao Deming and Tang Jinsheng, Function of
discordogenic faults during the forming of hydrocarbon pools.
Acta Petrolei Sinica, 1996, 17(3): 27–31.
[11] Zhuang Peiren, The study of fault structure. Beijing: Geological Publishing House, 1996. 11–28.
[12] Qiao Hansheng, Continental rift basins in east China and petroleum. Beijing: Petroleum Industry Press, 1999. 96–109.
[13] Wang Ping, The controlling mechanism of second- or
third-class faults for hydrocarbon migration and accumulation.
Fault-block Oil & Gas Field, 1984, 1(5): 1–5.
[14] Lei Maosheng &, Lin Tiefeng, A preliminary analysis of the
vertical flow conductivity of fault systems in the Songliao basin. Petroleum Exploration and Development, 1999, 11(1):
24–28.
[15] Zhang Shanwen, Wang Yongshi, Shi Dishi, et al. Meshwork-carpet type oil and gas pool-forming system: Taking the
Neogene of the Jiyang depression as an example. Petroleum
Exploration and Development, 2003, 30(1): 1–10.
[16] Sun Xiangyang &, Ren Jianye, Transfer zone and its reservoir
distribution in the northern zone of the Dongying Sag. Petroleum Exploration and Development, 2004, 21(1): 73–77.
[17] Zhang Junfang & Lan Chaoli, Fractures and faults distribution
and its effect on gas enrichment areas in the Ordos Basin. Pe-
References
troleum Exploration and Development, 2006, 33(2): 172–177.
[18] Gu Shusong & Xu Wang, Discussion of the article of “Appli-
[1]
Li Deshen, Collected Works of Academicians of the Chinese
cation of fault controlling hydrocarbon theory to realize a
Academy of Science. Beijing: Encyclopedia of China Pub-
great breakthrough of petroleum exploration in the Qaidam
lishing House, 1997. 55–77.
[2]
[3]
[19] Wang Zecheng, Zhao Wenzhi, Li Zongyin et al, Role of base-
of the rift system in east China. Acta Petrolei Sinica, 1980,
ment faults in gas accumulation of the Xujiahe Formation, Si-
1(4): 44–49.
chuan Basin. Petroleum Exploration and Development, 2008,
Luo Zhili. Plate tectonics and petroliferous basins in China.
Wuhan: China University of Geosciences Press, 1989, 15–54.
[4]
strike-slip faulting on the reservoir formation of oil and gas in
Geology and Mineral Resources. Geologic Dictionary I:
the Nanpu sag. Petroleum Exploration and Development,
Publishing House, 1983, 188–195.
Zhang Wenyou, Introduction of block structure. Beijing: Petroleum Industry Press, 1984. 305–334.
[6]
Zhu Xia, Meso-Cenozoic sedimentary basins in China. Beijing: Petroleum Industry Press, 1990. 23–34.
[7]
Lu Kezheng & Qi Jiafu, The structural models of Cenozoic
petroliferous basins in the Bohai Bay Basin. Beijing: Geological Publishing House, 1997. 200–234.
[8]
Chen Yixian, The evolution of faults and the formation of oil
and gas reservoirs in the Liaohe rift valley. Acta Petrolei Sini-
[9]
35(5): 541–547.
[20] Dong Yuexia, Wang Zecheng, Zheng Hongju, et al. Control of
Editorial Office of “Geologic Dictionary”, Ministry of the
Common geology and tectonic geology. Beijing: Geological
[5]
Basin”. Acta Petrolei Sinica, 2003, 24(6): 107–108.
Tong Chongguang, Some characteristics of petroleum geology
2008, 35(4): 424–430.
[21] Luo Zhili, Taphrogenic movement and petroleum distribution
in China. Beijing: Petroleum Industry Press, 1991. 22–58.
[22] Bao Ci, The natural gas geology. Beijing: Science Press, 1988.
56–65.
[23] Zhang Yigang, Natural gas generation, accumulation and
preservation. Nanjing: Hehai University Press, 1991. 36–48.
[24] Luo Qun, Jiang Zhenxue and Pang Xiongqi, The mechanism
and model of fault controlling petroleum accumulation. Beijing: Petroleum Industry Press, 2007. 8–45.
[25] Luo Qun and Bai Xinhua, The fault controlling hydrocarbon
ca, 1985, 6(2): 1–12.
theory and practices: Fault action and petroleum accumulat-
Zhang Wenzhao, Petroleum exploration practices in the conti-
ing. Wuhan: China University of Geosciences Press, 1998.
nental basins of China. Beijing: Petroleum Industry Press,
6–34.