production_optimization 外文资料

29-30th April, 2008
PMRE Department, BUET
Production Systems
• Production Systems includes
¾Reservoir (Inflow Performance Relationship) ¾Wellbore (Completions, Tubing etc) ¾Surface Facilities (Flow lines, Separator, Pipelines, etc )
29-30th April, 2008
PMRE Department, BUET
System Analysis
• Deliverability of a well can be severely restricted by the performance of only one component in the system • If the effect of each component on the total system performance can be isolated, the system performance can be optimized in more economic way • In system analysis we use a method where we consider whole production system as a single unit. Then we choose a point with in the unit where input and output pressure are same. • This is Nodal Analysis*
• Flow Characteristics
¾ Single phase ¾ Multiple phase
29-30th April, 2008 PMRE Department, BUET
Transport
• Ways and Means of transportations
¾ Pipeline ¾Tankers ¾ Others
• Production systems can be very simple to complex
¾ Simple – Reservoir, completion, tubing, surface facilities ¾ Complex- Artificial lift system, Water injection and Multiple wells
Production Optimization and Forecasting
Mohammad Sohrab Hossain
Assistant Professor Petroleum and Mineral Resource Engineering Department BUET
29-30th April, 2008
29-30th April, 2008 PMRE Department, BUET
Considerations
• • • • • Reservoir deliverability Lifting of Hydrocarbon Transport to Market Place Flow assurance & Operability Future oil and gas price, Time value of Money etc
29-30th April, 2008 PMRE Department, BUET
Reservoir Fluid
• Properties of the reservoir fluid, like
¾ FVF (Formation Volume Factor), Bo, Bg ¾ Produced Gas/Oil Ratio (GOR) Rp, ¾ Solution Gas Oil Ratio, Rs ¾ Compressibilities Co, Cg ¾ Bubble Point ¾ Gas and Oil Gravities ¾ Densities & Viscosities
• Upstream of node is called inflow • Down stream of node is called outflow • Node pressures are
¾ Inflow to the node ¾ Outflow from the node
P R − ∆Pupstream = Pnode
29-30th April, 2008 PMRE Department, BUET
29-30th April, 2008
PMRE Department, BUET
Production Systems…
• Movement or Transport of reservoir fluid from reservoir to surface requires energy to overcome the frictional losses or the pressure drop • The pressure drop of the fluid at any time would be the initial fluid pressure minus the final fluid pressure
∆P = Pi − Psep ∆P = P r − Psep
29-30th April, 2008 PMRE Department, BUET
−
Production Systems…
• Design of a production systems never be separated into reservoir and piping systems
PMRE Department, BUET
Production Optimization and Forecasting…
• Production optimization means – Balance between production rate / deliverability and demand • Production optimization includes a good understanding about Production Systems & Reservoir fluid
P
− sep
−
+ ∆ P downstream
= P node
PMRE Department, BUET
29-30th April, 2008
Nodal Analysis…
• Pressure drop dP varies with the flow rate q • Pressure VS. Flow rate will produce two curves
29-30th April, 2008
PMRE Department, BUET
Nodal Analysis…
29-30th April, 2008
PMRE Department, BUET
Nodal Analysis…
• Node at the well head
o Inflow Performance Relationship o Decline Curve Analysis
¾ Analytical Solutions ¾ Reservoir Simulations
29-30th April, 2008
PMRE Department, BUET
Lifting Hydrocarbon
29-30th April, 2008 PMRE Department, BUET
Flow Assurance and Operability
• • • • • Hydrate formation Paraffin & Asphaltene deposition Severe Slugging Start up and Shutdown Scale Formation
The amount of Oil and Gas flowing into the well from reservoir depends on pressure drop in the piping system Piping system pressure drop depends on amount of the fluid flowing through it
Pressure, Pnode
Outflow from node
Inflow to node
Flow Rate q
29-30th April, 2008 PMRE Department, BUET
Nodal Analysis…
• Intersection of Inflow and outflow satisfy the conditions • This P is the optimum for that flow rate • If any change is made anywhere ie inflow or outflow then only that curves will be shifted and other will be same • Intersection will be changed• low in Wellbore
¾Natural Flow ¾Artificial Flow (Water flooding, CO2 flooding)
• Flow in Tubing
¾ Natural Flow ¾ Artificial Lift (Gas lift, Beam Pump, ESP)
29-30th April, 2008 PMRE Department, BUET
Nodal Analysis
• Node is a point where –
¾ Flow into the node equals flow out of the node ¾ only one pressure exist in the node
29-30th April, 2008
PMRE Department, BUET
Deliverability
• Provides information on the production rate & Total production as a function of Time
¾ Simplified Approach
• Flows in pipes and piping components • Flow Control and Conditioning
¾ Flow rate adjustment ¾ Separation and disposal of “unwanted’ ¾ Pressure Maintenance (compressor & Pumps)
• Therefore, entire production systems must be analyzed as a unit
29-30th April, 2008 PMRE Department, BUET
A Hypothetical Case
• A new offshore gas condensate field has been discovered in the Bay of Bengal • Seismic studies and Well tests suggest a very large anticline structure, with possible reserves of 7.8 TCF of gas and 400 million barrels of condensate liquids • The offshore field is 150 miles off from the shore line