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Category Archives: Ingenieria de Produccion de Petroleo

LINERS EN COMPLETACIONES DE POZOS




Liners for Well CompletionsA liner is a string of casing that does not reach the surface. Liners are hung on the intermediate casing by use of a liner-hanger. In liner completions both the liner and the intermediate casing act as the production string.
Types of Liners
  1. Drilling liners are used to isolate lost circulation or abnormally pressured zones to permit deeper drilling.
  2. Production liners are run instead of a full casing to provide isolation across the production or injection zones.
  3. The tie-back liner is a section of casing extending upwards from the top of an existing liner to the surface. It may or may not, be cemented in place.
  4. The scab liner is a section of casing that does not reach the surface. It is used to repair existing damaged casing. It is normally sealed with packers at top and bottom and, in some cases, is also cemented.
  5. The scab tie-back liner is a section of casing extending from the top of an existing liner but does reach the surface. The scab tie-back liner is normally cemented in place.

Advantages of a liner:

The main advantages of a production liner are: (a) total costs of the production string are reduced, and running and cementing times are reduced; (b) the length of reduced diameter is reduced which allows completing the well with optimum sizes of production tubings. Other advantages include:

  • Complete wells with less weight landed on wellheads and surface pipe
  • A scab liner tie-back provides heavy wall cemented section through salt sections.
  • Permits drilling with tapered drillstring.
  • Where rig capacity cannot handle full string; when running heavy 9 5/8″ casing.
  • To provide a PBR (Polished Bore Receptacle) completion. This type of completion is recognised to be the best casing to tubing seal system.
  • Improved completion flexibility.
  • To provide an upper section of casing (tie-back liner) which had seen no drilling.
  • For testing in critical areas where open hole testing is not practised.

The disadvantages of a liner are:

(a) possible leak across a liner hanger; and
(b) difficulty in obtaining a good primary cementation due to the narrow annulus between the liner and the hole.



ADVANTAGES OF DIFFERENT ARTIFICIAL LIFT SYSTEMS




Balancin petrolero MECHANICAL PUMP

• System design relatively simple.
• Units can be changed to other wells at a minimum cost.
• Efficient, simple and easy to be operated.
• Applicable for slim hole (small diameter wells) and multiple completions.
• It can pump a well at very low pressure (depending on depth and flow)
• The system is naturally vented for gas separation and fluid level surveys.
• Analyze
• You can raise high oil viscosity and temperature.
• You can use gas or electricity as a source of power.
• Suitable for pump-off control
• Dsiponible in different sizes depending on the amount of lift.

HYDRAULIC PUMP

• You can pick up large volumes at high depths (500 bpd to 15 ft for example). Allows up to 18 000 ft.
• presents few problems in deviated wells.
• Your power supply can be installed remotely.
• You can also use gas or electricity as a source of power.
• Can pump medium pressure wells
• Suitable for multiple completions
• Suitable for offshore

Electrosumergible pumping

• You can raise huge volumes (20 000 bpd from shallow wells. Commonly up + / -120,000 bpd of water wells in the Middle East with 600HP units)
• Easy to operate.
• Easy to install a bottom pressure sensor for pressure via telemetry cable.
• No problem in deviated wells.
• Also suitable for offshore.
• Available in different sizes.
• Rising cost for high volume generally low.

GAS LIFT (LIFT GAS)

• Handles high-volume wells in high production rate (Gas lift continued) (50 000 bpd).
• Fairly flexible. Can be converted from continuous to intermittent.
• Your power supply can be remotely located.
• Rising gas wells does not present major problems.
• Wells diverted no problems except to remove and operate valves and wireline.
• Also suitable for offshore.

TIPOS DE VALVULAS DE GAS LIFT





Válvula de Gas Lift Convencional – Montada en la parte externa del tubing


Válvula para Gas Lift Recuperable - Corre adentro del mandrel dentro del tubing

DISADVANTAGES OF ARTIFICIAL LIFT SYSTEMS

In an earlier date had posted about the advantages of artificial lift systems, this post will find the disadvantages of each system:

MECHANICAL PUMP

Unobtrusive in urban locations.
Heavy and bulky ne Offshore operations.
Susceptible to problems of paraffins.
The tubing can not be covered against corrosion.
Presents problems of friction in deviated wells.
The high production of solid represeta a problem.
The production of gas wells lose volumetric efficiency.
It has limited depth, due mainly to capidad rod.

HYDRAULIC PUMP

Operation presents problems not so easy to operate by field staff.
Difficulty obtaining valid tests in low-volume wells.
Two strings of tubing required for some installations.
Power Oil System exposed to the danger of fire.
The high production of solids is a problem.
The need for venting makes the installation more expensive.

Electrosumergible pumping

The system is of limited depth (around 10 000 ft) due to the costs of cable and the failure to install sufficient power downhole.
The production of gas and solids are a problem.
Limiting the extent of the casing.
Not applicable for multiple completions.
Applicable only to elétrico.
Necessary high voltages (1000 V +/-).
Inapplicable to shallow wells.
Deterioration of cables at high temperatures.

GAS LIFT

The gas is not always available.
Difficulty lifting and crude viscous emulsions.
Problems and freezing of gas hydrates.
Difficult to remove valves highly deviated wells.

DIFFERENCES BETWEEN ACID WASH, ACIDIFICATION MATRIX AND ACID FRACTURING

Equipo de acidificacion
This will be a short post to talk strictly about the differences between different types of work performed acidification to the formation of which students are often present doubts.

As we know acidification is mainly used to dissolve some of the rock and undesirable materials are deposited within the formation and that apart from reducing PI (production index) may affect the plugging of the pierced, the flow in the tubing , rods, flow lines and other depending on the type of survey.

Well the goal is broad above, but how they differ:

A. ACID WASHING
In this operation the acid is placed against the area to be looking for the reaction without external pressure, hydrostatic pressure only. Acid thus paid more than about 1 foot into the training.

B. MATRIX ACIDIFICATION
Unlike earlier here does apply pressure but not to the point of fracturing of the rock, looking for a radial expansion of the acid.

C. ACID FRACTURING
As its name indicates, here it is achieved fracturing caused by a pressure above the point of fracture of the rock, which not only channel conductivity is achieved but also a large area which drain to prevent rapid plugging must be accompanied by a support agent such as sand fracturing.

In general, the acids used in the various operations are hydrofluoric, hydrochloric, hydrochloric, hydrofluoric. Formerly also used sulfuric acid.