Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Predicting reservoir system quality and performance

  | chapter = Predicting reservoir system quality and performance

  | frompg  = 9-1

  | frompg  = 9-14

  | topg    = 9-156

  | topg    = 9-16

  | author  = Dan J. Hartmann, Edward A. Beaumont

  | author  = Dan J. Hartmann, Edward A. Beaumont

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm

==Predicting drive type==

==Predicting drive type==

Reservoir analysis includes making cross sections, structural maps, and isopach maps. Analyzing nearby producing fields yields the best set of inferential data. This includes (1) making plots of historical oil, gas, condensate, and water production and pressure decline and (2) making cumulative production maps. When all available information has been assembled, find the drive type that best fits the prospective reservoir system. The table below summarizes typical characteristics of primary drive types.

Reservoir analysis includes making [[cross section]]s, structural maps, and isopach maps. Analyzing nearby producing fields yields the best set of inferential data. This includes (1) making plots of historical oil, gas, condensate, and water production and pressure decline and (2) making cumulative production maps. When all available information has been assembled, find the drive type that best fits the prospective reservoir system. The table below summarizes typical characteristics of primary drive types.

{| class = "wikitable"

{| class = "wikitable"

*  No decline while reservoir compacts, then rapid production decline

*  No decline while reservoir compacts, then rapid production decline

|-

|-

| Gravity

| [[Gravity]]

|  

|  

*  Steeply dipping beds or vertical [[permeability]] greater than horizontal  

*  Steeply dipping beds or vertical [[permeability]] greater than horizontal  

*  Fractured reservoir  

*  Fractured reservoir  

*  Low-viscosity oil (in general)  

*  Low-[[viscosity]] oil (in general)  

*  Rapid production decline  

*  Rapid production decline  

*  High recovery rate (75% or more), but often with low recovery volume

*  High recovery rate (75% or more), but often with low recovery volume

==Production history characteristics for drives==

==Production history characteristics for drives==

[[:file:predicting-reservoir-system-quality-and-performance_fig9-8.png|Figure 1]] shows oil reservoir production history characteristics for water, gas expansion, and gas solution drives. To predict reservoir drive type, if possible, plot the production history of nearby fields with analogous reservoir systems and compare with these graphs.

[[:file:predicting-reservoir-system-quality-and-performance_fig9-8.png|Figure 1]] shows oil reservoir production history characteristics for water, gas expansion, and gas solution drives. To predict reservoir drive type, if possible, plot the production history of nearby fields with analogous reservoir systems and compare with these graphs.

==Recoveries of oil vs. gas reservoirs==

==Recoveries of oil vs. gas reservoirs==

The table below shows typical recovery rates for oil vs. gas reservoir systems for different reservoir drive mechanisms with mega and macro port type systems (John Farina, personal communication, 1998; .<ref name=ch09r21>Garb, F., A., Smith, G., L., 1987, Estimation of oil and gas reserves, in Bradley, H., B., ed., Petroleum Engineering Handbook: SPE, p. 40-1–40-32.</ref> Recoveries would be lower for meso to micro port systems. Use this table to project the recoveries for your prospects.

The table below shows typical recovery rates for oil vs. gas reservoir systems for different reservoir drive mechanisms with mega and macro port type systems.<ref>Farina, J. personal communication, 1998</ref><ref name=ch09r21>Garb, F. A., and G. L. Smith, 1987, Estimation of oil and gas reserves, in H. B. Bradley, ed., Petroleum Engineering Handbook: SPE, p. 40-1–40-32.</ref> Recoveries would be lower for meso to micro port systems. Use this table to project the recoveries for your prospects.

{| class = "wikitable"

{| class = "wikitable"

|-

|-

! rowspan=2 | Reservoir drive mechanism

! rowspan=2 | Reservoir drive mechanism || colspan=2 | Percent ultimate recovery

! colspan=2 | Percent ultimate recovery

|-

|-

! Gas

! Gas || Oil

! Oil

|-

|-

| Strong water

| Strong water || 30–40 || 45–60

| 30–40

| 45–60

|-

|-

| Partial water

| Partial water || 40–50 || 30–45

| 40–50

| 30–45

|-

|-

| Gas expansion

| Gas expansion || 50–70 || 20–30

| 50–70

| 20–30

|-

|-

| Solution gas

| Solution gas || N/A || 15–25

| N/A

| 15–25

|-

|-

| Rock

| Rock || 60–80 || 10–60

| 60–80

| 10–60

|-

|-

| Gravity drainage

| [[Gravity]] drainage || N/A || 50–70

| N/A

| 50–70

|}

|}

==Recoveries for sandstone vs. carbonate reservoirs==

==Recoveries for sandstone vs. carbonate reservoirs==

The American Petroleum Institute conducted a study to determine recovery amounts and efficiencies for water vs. solution gas drives for sandstone and carbonate reservoirs, summarized in the table below (Arps, 1967). Use the table to project recoveries for your prospects.

The American Petroleum Institute conducted a study to determine recovery amounts and efficiencies for water vs. solution gas drives for sandstone and carbonate reservoirs, summarized in the table below.<ref name=Arps=1964>Arps, J. J., 1964, [http://archives.datapages.com/data/bulletns/1961-64/data/pg/0048/0002/0150/0157.htm Engineering concepts useful in oil finding]: AAPG Bulletin, v. 48, no. 2, p. 943-961.</ref> Use the table to project recoveries for your prospects.

{| class = "wikitable sortable"

{| class = "wikitable sortable"

==See also==

==See also==

* [[Reservoir system basics]]

* [[Reservoir system]]

* [[What is a reservoir system?]]

* [[Analyzing a reservoir system]]

* [[Analyzing a reservoir system]]

* [[Defining flow units and containers]]

* [[Defining flow units and containers]]

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Predicting reservoir system quality and performance]] [[Category:Pages with bad references]]

[[Category:Predicting reservoir system quality and performance]] [[Category:Pages with bad references]]