BMC – control stratergy

Control stratergy
|—-> Continuous control —–>P,I,D Control
|–>composite control
|                 |—> PI, PD,PID
|–>Optimality –> MPC(model predictive control),  LQG (linear quadratic gaussian control)

The point which lie on the pareto optimal curve are the points which are most optimal.

CLTF(closed loop transfer function):- Gc*Gp/(1+Gc*Gp*H)

OLTF(open loop transfer function):- Gc*Gp*H

The roots of the eqn in the numerator of a transfer function are called the zeros.

The roots of the eqn in the denominator of a transfer function are called the poles.

Total no of poles in a system is known as the order of the system.

Total no of poles lying at the origin determines the type of system. For eg:- if 2 poles value turns out to be zero, then its called a type-2 system.

Poles on the left side of the complex line can only be removed while on the right cant be because it makes the system unstable.

If any zero lies on the right side of the S-plane it is called non-minimum phase system.

If any pole lies on the right side of the S-plane then it is called unstable system.

Stability:- bounded i/p –> bounded o/p –> stable

Bounded i/p –> unbounded o/p –> not stable

unbounded i/p –> SP –> cant say ( cant comment on stability)

Transport phenomena types of fluids newtonian and non newtonian

Types of fluids:-

Newtonian

Non- newtonian

Newtonian fluids:- the fluids that follow the newtons criteria are called newtonian fluids.  Shear force= Ux/y    where Ux is velocity in x direction. And y is the distance from the layer of minimum velocity.

The variation in velocity is only for certain thinkness after which the velocity is constant ,It is called boundary layer thickness.

boundary layer exists for every fluid. the part of liquid where resistance to flow exists is called boundary layer.

Fluids do not sustain shear stress , they are deformed under the action of external force and eventually flows.

In general when we plot a hydraulic gradient to velocity graph for newtonian fluids we get 3 regions , first for laminar flow, then for transient flow  and the last one for the turbulant flow.

The region of transient flow is never the same for every time the experiment is repeated.

Eddies current:- for laminar flow such internal currents are generated.

Non- newtonian fluids:- that dont follow the newtonian criteria

properties:- apparent velocity depends upon the rate of shear and the previous shear history.

properties of both liquid and solid.

elasticity

heat and mass transfer coefficient are considerably affected by the behavior of the fluid.

2 types of non-newtonian fluids :-shear dependent , time dependent

For some fluids

Shear increases –> μa decreses –>shear thinning

shear increases –> μa increses –> shear thickening

Bingham plastic:- these need a minimum stress level to flow till that is achieved they behave like solids after that they behave like liquids.

Ry= μ( dUx/dy)^1-n         this is power model

n=0 newtonian

n>1 shear thickening

n<1 shear thinning

newtonian fluids

Petroleum geology Fate of organic matter

For the conversion of organic matter to petroleum you need atleast 2 things :- evolution of organic matter i.e abundance of organic matter and  preservation( need a platform area for deposition)

Platform:- water depth ≤ 200 m . this is generally the region where fine grain particles are deposited and they can preserver the organic matter at its best.

Preservation in coarse grains is not possible as water can move through its pore spaces and so does the oxygen which oxidizes the organic matter thus ceasing the chances of preservation.

vuggy porosity [ note: if there is a mistake here, plz post comment to get it corrected] :- vuggy porosity arises due to dissolution of carbonates like limestone.

Petroleum geology shales ,kerogens, bitumin overview

Oil shale:- shales containing oil are called oil shales. Oil was extracted from these shales by pyrolysis. pyrolysis is basically heating in absence of oxygen at 550° C .

Bitumin:- It is soluble in organic solvents , it is very well structured. Its of 3 types:-

a) labine -> very easily liberates hydrocarbon

b) inert -> high temp required for getting hydrocarbons

c) refractant -> can be used as an indicator of maturity in hydrocarbon source rocks, is a key method for identifying the temperature history of sediments in sedimentary basins.
(wiki pedia)

kerogens:- not structured and are insoluble in organic solvents, these the ones that have a good petroleum formation potential.

kerogen type-1   H:C ratio > 1.5

Vitrinite reflectance :- can be used as an indicator of maturity in hydrocarbon source rocks,  is a key method for identifying the temperature history of sediments in sedimentary basins.
(wiki pedia)

Catagenetic regime -> it comes after diagenisis stage and before metagenisis.  So VRo –> 0.5 – 2 %

Oil window -> VRo –> 0.7 – 1.3 %

Wish to know more,go here:-  petrocafe.us.to

Petroleum geology - Kerogens

Key learning of last two lectures:-

In a lagoon or silled condition we get more of sulphur while in an open water body (the water mass that is connected to the sea/ocean) we find less of sulphur in the sediments, this is because of presence of bacterias

In an open condition where there is agitation of air with water due to sea waves which dissolves the oxygen in water the bacteria Thiobacillus is found. This bacteria is responsible for converting sulphur in SO4. Thus decreases the content of sulphur in the sediments. The bacteria named desulfovibrio is responsible for the conversion of SO4 into S. In a Lagoon the oxygen content is depleted, so thiobacillus cannot survive as it is an aerobic bacteria and thus only desulfovibrio is present which converts the SO4 into S thus increasing the content of sulphur into the sediments.

Diagenesis:- Temp and pressure conditions for its initiation are:- 50 degree Celsius and pressure is 500-600 bar.  It is the process which is responsible for converting organic matter into kerogens.

Pristane – phytane :-

The presence of pristane and phytane in a crude is a supportive point for the organic theory of origin.

The chlorophyll when undergoes a oxydizing environment it finally yields the pristane and if goes through an reducing one the yields phytane. Thus depending upon the ratio of pristane to phytane we can make out what kind of environment was present during that period. These two are known as geochemical fossils.

The content of particulate organic matter is much less than dissolves organic matter in the ocean.

The process of formation of kerogen:-

Protein and polysaccharides(highly organic bipolymers) à enzymatic microbiological degradationà Amino acids and sugar (mononers) à random polymerisation and condensation à Fumic acid, humic acid, humin ( geo polymers) à increasing condensation and insolubalisation à Kerogens

Lipids(highly structured) à preservation with minor alteration yields kerogens

Organic matter obtained from algae is always saprophylic , which is rich in hydrogen and has less of NSO( nitrogen, sulphur and oxygen)

Type of kerogens:-

Type- 1 , type-2 , type-3

TYPE- 1 :-

Has high H:C ratio 1.5 or more

Has low O:C ratio less than 0.1  , small amount of oxygen that too in ester 4.6%

Much lipid material , particularly aliphatic.

Produces large yield of volatile and extractable compounds , upto 80% by wt prolific oil shales.

Sources:- selective ammulation of algae and severe degradation of OM. Abundance:- low

TYPE-2 :-

High H:C ratio

Low O:C ratio

Abundance ofModerate length chains of aliphatics and naphthenic rings

Rather abundant amount of ester group oxygen = 10.3 %

Can provide commercial oil shales but less than that of type-1

Source: Marine sediments of phytoplanktons , zooplanktons, bacteria deposited in reducing environment

Abundance:- abundant

TYPE-3 :-

Low H:C ratio less then 0.1

High O:C ratio 0.2 to 0.3

No ester group, oxygen content is still in other forms = 27.5 %

Less efficient for oil but a good gas source

Source:- continental plants

Abundance:- high

Get to know more at :- petrocafe.us.to

Transport phenomena manometers

Key learning in transport phenomena :-
Unit of viscosity in oil field units is:- centipoise
Dimensional equation:- The eqn having a constant which has units is called a dimensional eqn.
1 ft = 30.48 cm
1 ft^3 = 0.0283 m^3
Compressible fluids:- If density changes with pressure and temp. then the fluid is called compressible fluid.
Fluid is a substance that doesnt permanently resist distortion.
Static pressure of fluid flow is measured in the direction parallel to the flow of the fluid.
dynamic pressure is measured in the perpendicular direction to the fluid flow.
Static pressure has to be measured about 50 diameters away from any bends, to get the accurate values.

Petroleum geology Duplex theory of origin

Duplex theory of origin of petroleum
This theory says that initially the hydrocarbon may be formed abiologically due Fischer - tropsch reaction. Then it must be acted upon by the living organisms like bacteria thus giving rise to the organic hydrocarbon.
The Fischer tropsch reaction is in general the reaction of carbon monoxide with hydrogen giving rise to the hydrocarbon and water.
It can be given as follow:- C+ Fe+H+OH------>CH4+C2H6+C3H8+C4H10+FeO
CO2+HOH+Fe---->CH4+FeO
C+HOH+Fe-->CH4+CO2+H2
Temp needed is 500°C
Robinson in 1963 and Szatmari in 1986 explained the same theory in different forms. Szatmari used plate tectonics to explain it.