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Stratigraphically complex fields are those that exhibit a high degree of vertical and lateral heterogeneity that is directly controlled by the environment of deposition (Table 1). This heterogeneity occurs at all scales (see [[Geological heterogeneities]]). It can result in a highly variable distribution of rock properties within one reservoir and the division of a single stratigraphic interval into multiple reservoirs that act as independent, self-contained compartments.

Stratigraphically complex fields are those that exhibit a high degree of vertical and [[lateral]] heterogeneity that is directly controlled by the environment of deposition (Table 1). This heterogeneity occurs at all scales (see [[Geological heterogeneities]]). It can result in a highly variable distribution of rock properties within one reservoir and the division of a single stratigraphic interval into multiple reservoirs that act as independent, self-contained compartments.

==Degree of hetrogeneity==

==Degree of hetrogeneity==

{| class = "wikitable"

{| class = "wikitable"

|-

|-

|+ {{table number|1}}Tentative, relative depositional heterogeneity ranking of reservoir facies based primarily on Texas petroleum fields

|+ {{table number|1}}Tentative, relative depositional heterogeneity ranking of reservoir facies based primarily on Texas [[petroleum]] fields

|-

|-

! Depositional Environment

! Depositional Environment

! Heterogeneity Rank

! Heterogeneity Rank

|-

|-

| ''' Siliciclastic Systems '''

| colspan=2 | ''' Siliciclastic Systems '''

 

|-

|-

|   Submarine slope/fan/canyon fill, silty to muddy

|   Submarine slope/fan/canyon fill, silty to muddy

| 8.0

| 8.0

|-

|-

|   Fluvial or deltaic sandstone on carbonate shelf

|   Fluvial or deltaic [[sandstone]] on carbonate shelf

| 8.0

| 8.0

|-

|-

| 2.0

| 2.0

|-

|-

| ''' Carbonate Systems '''

| colspan=2 | ''' Carbonate Systems '''

 

|-

|-

|   Evaporitic flats (sabkhas)

|   Evaporitic flats (sabkhas)

| 8.5

| 8.5

|-

|-

|   Open shelves, extensive diagenesis

|   Open shelves, extensive [[diagenesis]]

| 8.0

| 8.0

|-

|-

* Questionable correlation of depositional packages between wells

* Questionable correlation of depositional packages between wells

* Presence of numerous vertical [[permeability]] barriers at a variety of scales

* Presence of numerous vertical [[permeability]] barriers at a variety of scales

* Complex [[porosity]]-permeability and [[capillary pressure]] relationships (a broad scatter in the data indicates different lithofacies and pore types)

* Complex [[porosity]]-permeability and [[capillary pressure]] relationships (a broad scatter in the data indicates different [[lithofacies]] and pore types)

* Anomalous changes in pressure gradient

* Anomalous changes in pressure gradient

* Variable oil and water chemical composition

* Variable oil and water chemical composition

[[Category:Geological methods]]

[[Category:Geological methods]]