Mechanical Solutions & Well Techniques

Question #1.

a) Determine the Paraffin Chemistry including generalized formula. (1)

Paraffin Chemistry - CnH2n+2

•Mixtures of Alkanes

•Plus Resins, Gums, Crude Oil, Sand, Silt, Clays, Salt, Scales and Water

•Melting Point varies from 98 0F to 215 0F

Paraffin

Melts over a narrow temperature range

Hot liquid has low viscosity

Burns rapidly with less smoke than asphalt

 leaves little residue

b) Discuss about Dry Sieving and LPSA methods. (1)

Dry Sieving

• Very common method

• Particles agitated during sieving so smallest dimension is

measured

• Not recommended to measure grains less than 44 μm

• Fines flocculate onto coarser grains – error in measurement

LPSA

• Laser diffraction - modern, fully automated method

• Average grain size measured over repeated passes of laser

• Laser diffraction measures from 2 mm to 0.1 μm

• No flocculation of fines

International testing standards state that dry sieving

Should NOT be used where the fines content is significant

c) Discuss about Ultra-fine Cement Squeeze as a water control method. (1)

Ultra Ultra-fine Cement ( Size - < 10 micron)

Better penetrability than conventional cement

• Small size casing hole

• Micro-channels

• Can be mixed with ultra fine silica

• Thermal stability

• Expensive

d)What kind material might you see during cleanup? (1)

Returns of Drilling Fluids

• Returns of Stimulation Fluids

• Returns of solids

• Returns of Water

• Returns of Nitrogen

• Returns of mixtures of the above, including well fluids.

E) List the Chemical Methods of Wax Removal. (1

•Solvents

•Dispersants

•Surfactants

•Crystal modifiers

f) Guidelines for Screen Selection. (1)

· Select largest slot size or micron rating possible (under confines of required retention efficiency)

• Determine screen permeability if convenient

• Larger open area of screen is better

• Screen strength should be considered (protective shrouds, etc.)

g) Discuss about Cross-linked Polymer System as a water control method. (1)

Physical Plugging Agents

Cross Cross-linked Polymer Systems

• Mainly acrylamide ter-polymer

• Organic or Inorganic cross-linker

• Variable concentration

• Low to very high viscosity

• Designable placement time

• Applicable in sand stone & carbonate

• Large volume application possible

• Applicable up to 140 0C

• Total sealant

Application

• Bottom water shutoff

• Coning

• Channel from Injector

• Casing leak

• Fracture into injector/aquifer

• Plugging operation/zone abandonment

• Gas shutoff

Question #2.

a) List the Sand Control Methods. (1)

No control

• Slotted Liner (SL)

• SAS (Wire-Wrapped)

• SAS (Shrink Fit)

• SAS (Shrouded Metal Mesh)

• Expandable Screen

• In Situ Consolidation (Resin)

• Oriented & Selective Perforating

• OHGP & IGP

• Frac Pack (Including Extension Pack or HRWP)

• Screenless Frac Pack

b) Determine the Cloud Point and Pour Point. (1)

•To determine Cloud Point (1)

use ASTM D 2500-66

•To determine Pour Point (2)

use ASTM D 97-66

•(1) the temperature at which the first wax crystals appear according to the standardized ASTM D2500-66 test protocol which is used to determine this temperature

•(2) the temperature at which the amount of wax out of solution is sufficient to gel the fuel when tested under standard ASTM D97 test protocol; it is a measure of the ability of a diesel fuel to operate (or not operate / flow) under cold weather conditions

c) Discuss about Advantages/ Disadvantages Wire-wrapped Screen. (1)

Advantages

_Trapiziform slots

_High manufacturing efficiency

_Profile materials can be stainless steel

• Disadvantages

_Inaccurate wire spacing can allow for production of formation sand or plugging

_Can be damaged when installed through doglegs, high angle and horizontal sections because of vertical orientation between wrapped wires and support rods

d) What do we mean by a stabilized flow and what would you look for? (1)

What do we mean by a stabilized flow?

• A well is considered to have "stabilized“ or reached stabilized flow when for a given choke size or producing rate, the flowing bottom hole pressure reaches equilibrium and remains constant.

• What would you look for?

_Constant wellhead pressure

_Constant gas production rate

_Constant oil production rate

e) List the mechanical solutions for water control. (1)

Water Control Solutions

•Mechanical

•Physical

•Chemical

Water Control Materials

Mechanical Solutions & Well Techniques

• Packers

• Bridge Plugs

• Casing Patches

• Infill Drilling

• Side Tracking

• Pattern Flow Control

• Horizontal

• Multilateral

f) Discuss about Punched Slot screens. (1)

Sand Exclusion Devices (Filters)

• Based on Slots:

_Slotted Liner

_Wire-WrappedScreen

_Punched Slot

• Based on Pores:

_Pre-Packed Screen

_Shrouded Metal Mesh Screen

_Expandable Screen.

About Punched Slot

• Developed in China circa 2000

• Stainless steel punched slot jacket on base pipe

_Good anti-corrosion characteristics

_Higher base pipe collapse strength without slots

_90°slots allow for greater flow area and reduced

plugging tendency

g) How would you identify that a well has cleaned up? (1)

• BS&W of less than 0.1%. On gas wells obtaining shakeouts with 10%+ condensate.

• Salinity stabilization near salinity of formation water.

• BHP and/or WHP stabilization.

• Flow rate stabilization.

• Ph indicating 5 (or above) or neutral after acidizing.

Question #3.

a) Discuss about Conventional Cement Squeeze as a water control method. (1)

Date: 2015-12-24; view: 595