He Zhiliang, Zhang Juntao, Ding Qian, et al. Factors controlling the formation of high-quality deep to ultra-deep carbonate reservoirs[J]. 2017, 38(4): 633-644.DOI: 10.11743/ogg20170401.
Based on our preliminary works and previous researches
we proposed a conceptual model of five main factors controlling the formation of carbonate reservoirs
including tectonics
sequence
lithofacies
fluid and timing.Tectonics exerted influences on the reservoirs through prototyping and deformation.The former controlled the sedimentary pattern and the latter
such as the formation and evolution of ancient uplifts
the development of folds and fractures
and the combination of fractures
provide a new macro background for a late diagenetic transformation.A brand new geological fluid-rock interaction environment could be formed through the intervention of thermal events and new fluids.The structure and style of stratigraphic sequence provided a macroscopic environment for reservoir development and distribution.Boundaries of relatively higher order of sequence controlled mainly the formation of scaled karst reservoirs
while those of relatively lower order of sequence were closely related to the development and distribution of reef-facies reservoirs in platforms and their margins
which also acted as channels of inter-layer karst fluid migration.Lithofacies
including sedimentary and diagenetic facies
were the basis of a later fluid transformation and the place where reservoirs were finally sat.The differences of modifiability of different original mineral components and the structures could affect the development of reservoirs.The effects of fluids existed all the way through the formation and reconstruction of carbonate rocks.Open geological fluid environment contributed to the formation of reservoir spaces
while closed geological fluid environment contributed to the preservation of reservoir spaces.Timing refers to the whole process of carbonate formation from sedimentation to diagenetic transformation and finalization
which involved the continuous processes of and the relationships between the geological effects controlled by the above four factors.Tectonics
sequence
lithofacies
fluid and timing were closely related to one another
and each played different and inseparable roles in the formation and preservation of carbonate reservoirs.In general
large-scale high-quality carbonate reservoirs are resulted from the combined effects of multiple factors through multi-stages.