Oil & Gas Production theory cocnepts.ppt

Oil & Gas Production theory concepts

1. Production Concepts
E0 Competency

2. Overview of Presentation
Reservoir and drive mechanisms
Production and Process
Introduction to well fluid
Production and process parameters
Production operations
Separation and refining process

3. Reservoir
The subsurface pool of
hydrocarbons

4. Reservoir Drive Mechanisms
Solution Gas Drive
Water Drive
Gas Cap Drive

5. Production and Process
All the well related activities, that are being carried out at field
(After Drilling of a well), to get the well fluid up to the
surface are referred to as Production Activities.
All the activities that take place on the produced fluids such as
separation, refining etc. are referred to as Process
operations.

6. Well Fluid
The fluid, which comes out of the oil or gas well is known as
well fluid and it may have desired or undesired fluid.
For oil wells:
Crude oil;
Natural gas;
Formation water;
For gas wells:
Natural gas;
Condensate;
Formation water;
Various impurities may also be present in the well fluids like
sand, H2S,CO2, NOX etc.

7. Production and Process Parameters
Main production/ process parameters are as follows:
Pressure;
Temperature;
Flow rates;
Gas Oil Ratio (GOR);
Water Cut;
API Gravity; etc.

8. Production operations
Production
Operations
Activation
Drilling and
Completion
Transportation
Marketing
Refining
Process
Treatment
& Separation
Storage

9. Activation
The activation process, also known as Enlivening of a well, refers to the process of bringing a well on
production after the well is perforated and the well is in a no flow state.
It can be done through a number of processes viz.:
Displacement
Compressor application
Application of Nitrogen
Aerisation
Swabbing
Use of Artificial lift

10. Production/ Process Operations
It covers a wide range of activities
viz.
Well Testing
Well Performance
Artificial Lift
Workover Operations
Well Stimulation Operations
Pressure Maintenance
Corrosion Control
Process Safety
Transportation
Process & Offshore Systems

11. Process treatment and separation
Separator
Dehydration
Compressor
Desulphurization
Denitrogenation
Emulsion Treater
Produced water treatment
Water
Gas
Oil
Sweet gas
If N
2also present
Sour gas
If N
2 present
If no N
2present
Heat
Exchanger
Manifold
Fluid stream
from different
wells
Storage/Transportation
Sale or
Flaring
Disposal / Injection well

12. Well Testing
It is the process of carrying out a series of tests on an oil or gas well to obtain various
parameters and data to analyze, rectify or predict the borehole conditions and the
reservoir performance.
It is the first activity that needs to be carried out after completion of a well repair job or
on recompletion of a well.
Through well testing, a number of information are obtained or derived for evaluating the
performance of reservoir, the job done in the well, equipments installed etc.
It comprises of the following:
Single zone testing
Multi-zone testing

13. Well performance
The production team is responsible for assessing whether or not the well is able to
produce to its maximum possible capacity and if not, then what are the reasons
behind it.
For this, they carry out the following tests on the wells:
Pressure Drawdown Testing;
Pressure Buildup Testing;
Multiple Rate Testing;
Injection Well Testing;
Deliverability Testing of Oil Wells;
Using the results from these tests, following are prepared for estimating the well
performance:
Productivity Index( PI);
Inflow Performance Relationship curves;
Outflow Performance curves;
Skin;

14. Artificial Lift
The Artificial methods are used when the reservoir is not able to produce the fluids
through the wells as the reservoir energy is insufficient to lift the produced fluids to
the surface.
The following methods are used:
Sucker Rod Pumping;
Progressive Cavity Pump;
Gas Lift;
Plunger Lift;
Electrical Submersible Pumps;

15. Workover Operations
Once a well is completed and put on production or injection, at some stage of its
operating life, it may produce /receive fluids below its capacity due to either
formation related or mechanical problems or both.
The following may be encountered:
Reservoir problems;
Flow restrictions in the tubing;
Wellhead or Casing failure;
Completion of a new zone;
Cementation problems;
Repair or replacement of faulty equipments;
A Workover rig

16. Well Stimulation
It might so happen that the well may not be producing effectively due to plugging of
pores by sand, paraffins and asphaltenes, debris from perforation charge etc. such
wells need stimulation jobs which are as follows:
Surfactant Flooding;
Acid wash/ Acidization;
Matrix Acidization;
Hydraulic Fracturing, etc.;
A Fracture job 

17. Pressure Maintenance
When the reservoir pressure has declined below the threshold energy levels, required to
lift the produced fluids up to the surface, then pressure maintenance is looked upon
as an alternative.
The various methods for pressure maintenance are :
Water Injection
Gas Injection;
These are used when sufficient amounts of
suitable resources are available.
A schematic of Water injection process

18. Corrosion Control
Corrosion control is an essential activity that must be carried out to ensure optimum and
smooth working of the various equipments that are installed to exploit the reservoir,
because replacing an equipment in the midst of production operations is a very
costly, cumbersome and also sometimes risky affair.
For this, several procedures are followed:
Addition of Corrosion Inhibitors;
Pigging( done in pipelines);
Cathodic Protection;
Maintaining temperature levels;
Use of sand packs/gravel packs
opposite sand producing formations;
Remedial cementing;

19. Process Safety
As the oil and gas produced from a well are highly inflammable and a small mistake
result in a mishap, so certain standards need to be adhered to using equipments,
processes.
A number of equipments are required keeping in mind the safety considerations such as:
Sub Surface Safety valves;
Surface Safety valves;
Packers;
Pressure/ Temperature Gauges;
Also, environmental safety measures should be kept in mind while carrying out all the
operations.

20. Transportation
Once the fluid comes out of the well bore, it needs to be transported to the treatment at
gathering stations.
Normally, pipelines are used to carry the fluid from well site to such stations.
After treatment, the oil needs to be transported to refineries for further treatment, for
which these modes may be used:
Railway Tankers;
Tankers( for sea routes);
Onland Transportation;
Pipelines;

21. Central Tank Farm

22. Offshore platforms
Wellhead Platforms
Process Platforms

23. Well Platform

24. Crude oil Refining