chapter 5 vocabulary reservoir performance

Question 1

Any substance that flows and yields to any force tending to change it shape is a . Both liquids and gases are fluids.

Answer 1

Fluids

Question 2

the density measure used for petroleum liquids. Expressed in degrees. The higher the______the lighter the liquid. formula for _____ = 141.5/S.G. – 131.5 (S.G. - specific gravity).

Answer 2

API gravity

Question 3

Defined as hydrocarbons that are in a gaseous state at standard conditions of one atmosphere (14.7 psi) and 60deg F. Included are methane, ethane, propane, and butane.

Answer 3

Petroleum Gases

Question 4

the minimum saturations of oil, water, or gas in the reservoir that cause the fluid to be a continuous medium, and therefore producible.

Answer 4

Critical saturations

Question 5

• gas that is in solution in the oil under the initial reservoir pressure and temperature. Under these conditions, the gas is in the liquid state.

Answer 5

Solution gas

Question 6

the percent or fraction of the reservoirs original oil in place (OOIP) or original gas in place (OGIP) that will be recovered. Expressed in percent.

Answer 6

Recovery factor

Question 7

is from solely gas reservoirs where no “black” (non-condensate) oil is present.

Answer 7

Non-associated gas

Question 8

• includes solution gas and gascap gas. They both occur only in association with oil.

Answer 8

Associated gas-

Question 9

is free gas trapped in the top of the structure above the oil leg.

Answer 9

Gas Cap-

Question 10

ratio of gas to oil produced or in solution in the reservoir. Units are in ft3 /bbl. or m3 /bbl.

Answer 10

Gas oil ratio (GOR)-

Question 11

Beta is the factor for the volume change undergone by the reservoir fluids when they are produced. In the case of oil, it is the ratio of the space occupied by a barrel of oil at reservoir conditions to the space occupied by a stock tank barrel (STB) of the oil. Most oils shrink when their solution gas dissipates at the surface and because of the cooler surface condition, so their Betas are greater than 1.

Answer 11

Formation volume factor (B)-

Question 12

a fluids resistance to flow. The thicker and stickier the fluid. The higher its ______.

Answer 12

Viscosity (u)-

Question 13

a light hydrocarbon liquid formed by condensation of petroleum compounds that were in the gaseous phase under initial reservoir conditions. It is highly volatile and from clear to a light yellow in color

Answer 13

Condensate

Question 14

when a reservoir is above its ___ ___ __, it has no free gas—all gas is in solution in the oil. As the reservoir is produced and pressure declines, the _____ _____ ____ is reached. Gas comes of solution, forming a free gas saturation.

Answer 14

Bubble point pressure

Question 15

is used to refer to all the artificial drive mechanisms such as waterflood, CO2 flood, steam injection, etc.

Answer 15

Enhance recovery- or improved recovery

Question 16

producing the reservoir using only the natural reservoir energy.

Answer 16

Primary recovery

Question 17

the initiation of additional recovery processes like waterflooding immediately without waiting for primary depletion.

Answer 17

Pressure maintenance

Question 18

a process that adds energy to the reservoir following primary recovery. An example is waterflooding a depleted field.

Answer 18

Secondary recovery

Question 19

follows secondary recovery. For example, CO2 flooding could follow waterflooding, which had followed primary recovery.

Answer 19

Tertiary recovery

Question 20

know whats there, no two reservoirs behave identically when produced.

Answer 20

Fluid systems

Question 21

naturally occurring near solid hydrocarbon. Must be mined.

Answer 21

Bitumen

Question 22

tar or heavy oil, low-shrinking oils (black oils), high shrinking oils (volatile oil), condensate gas, wet gas, dry gas

Answer 22

Fluids

Question 23

with more lighter ends than bitumen and small amount of gas in solution, it flows sluggishly through the reservoir

Answer 23

Tar or heavy oil

Question 24

oils viscosity is low enough for it to move through the formation readily, normally commercially producible

Answer 24

Low shrinkage oils (black oils)

Question 25

because of its low viscosity, volatile oil produces at high rates and it high Rs ( ) results in high good recovery factors

Answer 25

High shrinkage oils (volatile oils

Question 26

hydrocarbons in reservoir are gaseous at initial conditions. During initial gas production, large quantities of condensate drop out in the surface facilities

Answer 26

Condensate gas

Question 27

All hydrocarbons are in a gaseous state. When gas is produced, the associated cooling causes condensate to drop out in the surface facilities.

Answer 27

Wet gas

Question 28

gas is composed primarily of methane with small amounts of ethane, propane, and butane. These reservoirs produce no condensate

Answer 28

Dry gas

Question 29

most widespread reservoir drives. Four phases 1. Production starts, reservoir pressure declines rapidly to the bubble point. 2. The GOR (gas to oil ratio) dips below the solution GOR for a short period. 3. Gas saturation exceeded. 4. Depleted of it gas

Answer 29

Solution gas drive

Question 30

have access to aquifers that provide water to replace some or all of volume fluids produced. Provide the highest recovery rates.

Answer 30

Water drive

Question 31

free gas trapped in the top of the structure above the oil leg

Answer 31

Gas cap drive

Question 32

pressure depletion of reservoirs.

Answer 32

Gravity drainage

Question 33

- overpressured reservoirs. North sea chalk fields example of this

Answer 33

Compaction drive

Question 34

there are no liquid hydrocarbons in the formation. Gas has lower viscosity than oil (

Answer 34

Wet and dry gas reservoirs

Question 35

initially very profitable, but it can fall off dramatically; loss of revenue from condensate sales; liquid build up in the formation restrict its permeability to gas; good candidate for recycling if found in remote area from the market.

Answer 35

Retrograde condensate gas reservoir

Question 36

dominant recovery method, used worldwide. Advantages saltwater availability, chemical compatibility, equipment availability, safe non toxic non flammable

Answer 36

Waterflooding

Question 37

saltwater and oil do not mix.

Answer 37

Fluid displacement

Question 38

water not oil adheres tightly to the surface of the sand grains.

Answer 38

Wettability

Question 39

the attraction between a surface and its wetting fluid.

Answer 39

Capillary forces

Question 40

how much the reservoir rock is actually contacted by the advancing water. It is effected by its mobility ratio.

Answer 40

Sweep efficiency

Question 41

fluids ease of movement through the reservoir.

Answer 41

Mobility ratio

Question 42

- five spot pattern- water injected to gently encroach from the perimeters of the field

Answer 42

Injection well patterns

Question 43

used to inject heat into the formation

Answer 43

Thermal recovery

Question 44

compressed air is forced down the well providing oxygen to ignite the oil

Answer 44

Fire flooding

Question 45

- steam injected is used in fields that are 2 ½ acres (shallow wells 200-500ft)

Answer 45

Steam flooding

Question 46

huff and puff. The most successful thermal recovery.

Answer 46

Cyclic steam flooding

Question 47

mix with

Answer 47

Miscible

Question 48

reservoir is flooded with fluid that are miscible the reservoir oil

Answer 48

Miscible flooding

Question 49

the CO2 combines with the oil, swelling and reducing its viscosity. Used the most

Answer 49

Carbon dioxide flooding

Question 50

is miscible in crude oil. But lpg is not recovered

Answer 50

Liquefied petroleum gas (LPG)

Question 51

waste gases from burning oils used.

Answer 51

Flue gas

Question 52

only at high pressures

Answer 52

Nitrogen

Question 53

cost is too great to use

Answer 53

Detergents

Question 54

unpleasant and unsafe to handle

Answer 54

Alkaline (caustic)-

Question 55

the high cost of chemicals limits commercial application

Answer 55

Mobility ratio improvement

Question 56

- bacteria used to reduce oil viscosity ( to slow )

Answer 56

Microbial floods

Question 57

estimated volumes of crude oil, condensate, etc., anticipated to be commercially recoverable from known accumulations

Answer 57

Reserves

Question 58

can be estimated, must have operational facilities to process and transport the reserves to market.

Answer 58

Proved reserves

Question 59

can’t estimate; divided in two risk classification; probable and possible

Answer 59

Unproved reserves

Question 60

because of uncertainties in both the counting and pricing of reserves while they are still in the ground.

Answer 60

Reserves are not assets

Question 61

Both liquids and gases are

Answer 61

fluids

Question 62

When there is a gas cap, the reservoir is at

Answer 62

bubble-point pressure

Question 63

Oil viscosity is measured in

Answer 63

centipoise (cp)