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Polymer gel systems for drilling fluid loss control and isolation work in oil and gas wells

THERMOGEL and THERMOGEL HT are solids-free fluids. They are pumped as liquids and turn into an elastic gel inside the formation, sealing fractures, channels and leaks during drilling, workover and restoring the tightness of well casings.

Request a treatment design
Since2004
Field treatments351
Technical successAbout 85%
Bottomhole temperature0 to +200 °C

Applications

19 jobs

Lost circulation while drilling

Partial, severe and total losses, including depleted zones and wide fractures

30 jobs

Water shutoff

Selective isolation of water inflow in producing wells

13 jobs

Conformance control

Improving the injection profile in injection wells

Preparation for P&A

Isolation of permeable intervals and annuli before abandonment

269 jobs

Casing and connection leaks (SCP)

Sealing gas leaks through casing threaded connections and wellhead seals; annulus pressure disappears or drops substantially

20 jobs

Gas venting to surface (SAGF)

Sealing of gas migration channels behind casing that feed gas venting through the ground around the wellhead

Products

Two systems, chosen by bottomhole temperature. Both are solids-free, low-viscosity fluids that pass through MWD/LWD tools, mud motors and bit nozzles, and both are mixed and pumped with standard rig or cementing equipment.

THERMOGEL, gelation activator and THERMOGEL HT containers
THERMOGEL, gelation activator and THERMOGEL HT
0 to +150 °C

THERMOGEL

System
Two fluids: polymer solution and gelation activator, separated by a water spacer
How it gels
In seconds where the two fluids meet in the zone; gel time adjustable from 30 s to 10 days
Bottomhole temperature
0 to +150 °C
Viscosity before gelation
60–100 mPa·s
Gelation pause
4–8 h before loading the zone
Removal
12–18% hydrochloric acid
Supply
Dry product in 15/20 kg bags, or ready-to-use solution in 1,000-litre IBCs
Typical volume per job
5–30 m³ of each solution
HSE
Not classified as hazardous (CLP); not dangerous goods for transport
Technical data sheet THERMOGEL (PDF)
50 to 200 °C

THERMOGEL HT

System
One fluid, no crosslinker
How it gels
From formation heat, above the set gelation temperature
Bottomhole temperature
50 to 200 °C (gelation temperature set at 40–200 °C)
Viscosity before gelation
40–100 mPa·s
Gelation pause
4–8 h
Removal
Cooling, or 12–18% hydrochloric acid
Supply
Same
Typical volume per job
10–100 m³
HSE
Same
Technical data sheet THERMOGEL HT (PDF)
Gel formed after contact with the gelation activator
Gel formed after contact with the gelation activator
Elastic gel in a tilted glass
Elastic gel: does not flow out of a tilted glass

Supply

THERMOGEL dry product
THERMOGEL dry product
Ready-to-use solution in 1,000-litre IBCs
Ready-to-use solution in 1,000-litre IBCs

Lost circulation while drilling

THERMOGEL enters fractures and channels as a liquid and gels inside them. The seal is formed in depth, not only as a filter cake at the wellbore wall, so the zone holds when mud weight or ECD goes up.

How a job is done

  1. The bit is set just above the loss zone. The drilling BHA with MWD stays in the hole.
  2. The fluids are pumped down the string with the annulus open, separated by water spacers.
  3. The annulus is closed and the fluids are squeezed into the zone below the agreed surface pressure.
  4. The bit is pulled above the zone; after a 4–8 h pause, drilling resumes. The soft gel is drilled or washed out with a standard bit and removed by the shakers.

Total losses with no returns: staged injection with support on bottom. Wide fractures and caverns: a bridging stage with LCM or dry THERMOGEL powder first, then the gel. THERMOGEL is used where LCM pills and cement plugs have failed.

48 → 0m³/h
1 stagethrough a BHA with MWD
About 15 hfrom start of pumping to drilling ahead
500 mdrilled to section TD without losses
Diagram of gel placement in a lost circulation zone
Mud losses while drilling before treatment
Before treatment: mud losses while drilling
Drilling ahead without losses after treatment
After treatment: drilling ahead without losses

Water shutoff and conformance control

THERMOGEL HT is placed across producing intervals for selective water shutoff. Example: after treatment a producing well flowed water-free at about 70 t/d of oil and 45,000 m³/d of gas.

THERMOGEL HT gel screen isolating a water-bearing layer

In injection wells the gel screen improves the injection profile for 3–5 years.

Both gels are removable with 12–18% hydrochloric acid; THERMOGEL HT can also be liquefied by cooling. Before work in a reservoir we run return-permeability and compatibility tests on the client's core and fluids.

Wellhead and pumping equipment ready for a conformance treatment in an injection well

Wellhead and pumping equipment ready for a conformance treatment in an injection well

SCP and SAGF: risks and causes

Sustained casing pressure (SCP) and surface annular gas flow (SAGF) can lead to uncontrolled gas releases, fires and explosions.

SCP

SCP: gas pressure builds up in the annulus between casing strings and can escape through the wellhead seals.

SCP has many possible sources. Our SCP treatment removes two of them: gas leaking through casing threaded connections and gas leaking through wellhead seals.

SCP remediation

  1. Performed during workover, after the well is killed and the producing interval is isolated.
  2. The tubing shoe is placed in the lower part of the production casing, with the annulus open.
  3. The gelation activator and THERMOGEL are injected one after another with full flushing between them, and move down the annulus in cycles.
  4. Pauses and overpressure are used to treat the whole interval from the wellhead to the tubing shoe.
  5. Such treatments extend trouble-free operation of ageing wells without major workover.

Result: after treatment the annulus pressure either disappears completely or drops substantially.

Casing leak 500 → 305 bar in 30 min before treatment; pressure test to 500 bar with no decline after.
Diagram of SCP sources, with treated sources highlighted
Ready-to-use THERMOGEL delivered to a workover rig
Ready-to-use THERMOGEL delivered to a workover rig

SAGF

SAGF: gas migrates outside the well and vents to surface through the ground around the wellhead (gas griffons).

SAGF remediation

  1. Preparation. The well is killed and the producing interval is isolated as part of a standard workover. The treatment interval is chosen where logs show gas migration behind the casing.
  2. Cement plug. A cement plug is set in the production casing below the treatment interval.
  3. Perforation. Three special perforations are made, evenly spaced between the top of the cement plug and the packer setting depth.
  4. Equipment. A packer is run on tubing and set above the perforations.
  5. Injection. Through the tubing and perforations to the space behind the outer casing, in sequence: gelation activator → water spacer → THERMOGEL → a small volume of cement to fix the gel screen.
  6. Result. The gel forms a continuous screen behind the outer casing that stops gas migration to the wellhead and to the atmosphere.

The gas migration channel is sealed during a standard workover. This extends safe, trouble-free operation of ageing wells.

Diagram of gas migration before and after treatment
Gas venting crater next to a wellhead
Gas venting crater next to a wellhead (griffon)
Poor cementing quality
Poor cementing quality
Uncontrolled gas venting around a wellhead
Uncontrolled gas venting around a wellhead

Causes

  • Violations of well construction or casing running practice
  • Leaks in casing threaded connections
  • Leaks in wellhead seals
  • Poor cement bonding
  • Gas migration while the cement sets

Consequences

  • Risk of accidents, including gas releases and fires
  • Need for permanent safety measures
  • Methane emissions

Lab Data

Tested in April 2026 by an independent drilling and cementing fluids laboratory. In the disc and core tests the limit was the test cell (700 psi), not the gel. Full report available under NDA.

THERMOGEL modelPressure heldGel penetration
Leaking threaded connection, 1/4"150 bar (2,200 psi), stopped for safety—
Channel in cement, 1.0 mm60 bar (870 psi)2–3 cm
Core disc 8,000 mD48 bar (700 psi), cell limit3–5 mm
Core 0.25 mD48 bar (700 psi), cell limit0.5–2.5 mm
Proppant-pack fracture, 300 D17 bar (250 psi)3–4 cm
Both gels fully broken by 18% HCl in 24 minutes. THERMOGEL gel stable 30 days at 90 °C in contact with oil-based mud.
Channel-in-cement model
Channel-in-cement model: 1 mm gap
Gel recovered from threaded connection model
Gel recovered from the leak path of the threaded-connection model
Gel in test cell after 700 psi
Gel on the disc inside the test cell after 700 psi
Ceramic disc after the test: gel layer on the surface
Ceramic disc after the test: gel layer on the surface
Proppant pack consolidated by THERMOGEL
Proppant pack consolidated by THERMOGEL
Core sample after THERMOGEL treatment
Core sample after THERMOGEL treatment

Cases

Selected field results. Wells and operators are not named. References from current clients are available on request.

Gas-condensate well, 8 3/4" hole, ~3,100 m, 2026

Problem Losses 45–48 m³/h in depleted sands; LCM and another sealant failed

Treatment 1 stage through a BHA with MWD: 6 m³ THERMOGEL HT, 6 m³ gelation activator, 6 m³ THERMOGEL

Result Zero injectivity at ECD 1.17 sg; 500 m drilled to TD at full flow rate, including 50 m of over-pressured formations

Deep exploration well, 3,547–3,600 m

Problem Catastrophic losses; 140 days of failed attempts; 240 m³ of 1.76 sg mud lost

Treatment THERMOGEL HT with support on bottom, 3 stages, 79 m³

Result Zone isolated in 6 days; well saved from abandonment

Exploration well, conductor section

Problem Total losses at 64 and 167 m in fractured hard rock; 40 days of failed attempts

Treatment THERMOGEL with dry THERMOGEL as swelling LCM, 2 stages, 25 m³

Result Both zones isolated in 2 days

Depleted zone while drilling, ~3,000 m

Problem 38 m interval, formation pressure 65 bar, pressure coefficient 0.17

Treatment 10 m³ THERMOGEL

Result Gel screen held 285 bar differential during further drilling

Exploration well, 9 5/8" casing

Problem Leak 500 → 305 bar in 30 min

Treatment THERMOGEL, staged over the full casing length

Result Pressure test 500 bar, no decline

Production casing leak: pressure test before treatment
Production casing leak: pressure test before treatment
After treatment: no pressure decline
After treatment: no pressure decline
ApplicationJobsSuccess criterion
Production casing leak remediation269Casing fully tight
Water shutoff in producers30Water inflow isolated, water cut reduced
Behind-casing crossflow elimination20Behind-casing flow eliminated
Lost circulation while drilling19Drilling resumed without losses at the required mud weight or ECD and flow rate
Conformance control in injectors13Injection profile improved

351 treatments since 2004 — 306 THERMOGEL, 45 THERMOGEL HT; about 85% technical success; repeat treatments no more than 2%.

Risks

Main operational risks and how we control them.

Risk

Premature gelation in the string (THERMOGEL)

Control

Water spacer between the two fluids; volumes tracked as a running total with fixed control points. No such event in any of our jobs

Risk

Premature gelation (THERMOGEL HT)

Control

Gelation temperature set above circulating temperature; no long stops while the fluid is in the pipe

Risk

Excessive pumping pressure

Control

Squeeze rate lowered to keep surface pressure below the agreed limit

Risk

Fluid entering the producing formation

Control

Bit above the zone, exact displacement volume; in well integrity jobs the producing interval is isolated first. Gel is removable with acid

Risk

Drill-out

Control

Soft gel, standard bit; gel pieces removed by the shakers; no change of mud rheology or filtration observed

Services

We provide each treatment as a complete service:

  • Well-specific treatment design: recipe, volumes, pumping sequence and pressure limits
  • Laboratory tests on the client's core, mud and mixing water
  • Supply of products, dry or as ready-to-use solution in IBCs
  • Rig-site compatibility tests and supervision during mixing and pumping
  • Job report

Documents: technical data sheets (download); safety data sheets and the laboratory report on request.

Send us your well data
THERMOGEL ready-to-use solution before dispatchTHERMOGEL ready-to-use solution before dispatch

Contacts

Email:s.ponomarev@utec.eu.com
Phone:+371 26020833
Website:www.utec.eu.com
Company address:

SIA “UTEC – Universal Technological Engineering & Consulting”
Reg. No. LV40203496170
Ošu iela 18, Mežāres, Babītes pagasts, Mārupes novads, LV-2101, Latvia