Deepearth Solutions: Thermax – Resource Control Technologies

Developed in Canada, Thermax is an organometallic compound with exothermic properties. These field proven compounds generate thermodynamic isometric characteristics during the setting process. (Volume Thermal Expansion). Composed of finely divided powders with medians down to 7 microns. They are 100% inorganic and totally environmentally safe.

They are unaffected by chlorides and will physically bond into salts. (This includes Zechstein type formations), 100% acid soluble in 15% HCL with no residue, they have the ability to totally protect a producing formation from damage due to cement , drilling fluids, brines etc:

They are able to withstand high levels of both organic and inorganic contamination with no adverse effect on the setting process.

Their  natural exothermicity ,(they generate heat internally when mixed , the amount of heat depending on the chosen reactivity, this is why they work in either hot or cold environments such as the arctic), of these compounds is accelerated rapidly by the application of, (being exposed to ), formation temperature. This causes the right angle setting characteristic. Nothing else affects this setting characteristic. Hydrostatic has no effect on it. Thermax compounds have a flat linear viscosity profile all the way up to the set point when they change to an exponential right angle. This means that they retain their fluid flow properties right up to the set point with, (unlike conventional Portland type cements),  ‘zero gel strength generation.

As a consequence these compounds “do not allow gas, water or oil transition between the fluid and set states thus eliminating channeling”. They do not shrink and will physically bond onto oily casing etc;

Thermax is the ‘only’ product which generates compressive strength, approved by Shell Expro  to pump’ through the bit’.

In many areas of the World formation damage to a production zone during both the drilling phase and various workover operations can result in a large loss of production when the well is brought back on or, in expensive remedial operations, such as fracturing and acidizing.

Damage due to cement , drilling fluids etc; is well documented. There is no such thing as a ‘non-damaging drilling fluid’ only more or less damaging. If the rate of deposition, of a filter cake, equaled the rate of erosion in a dynamic situation then fluid invasion would still occur. Thermax is impermeable ,(0,012md), when set and does not allow the deposition of drilling fluid filter cakes.

Thermax offers the opportunity to eliminate formation damage. It is non invasive in a production zone. This is best illustrated by an analogy- if you place a container with Thermax in a hot frying pan it will heat from the bottom up.Depending on temperature the whole can will set in around 60-120 seconds ‘once the set point is reached.

If you take the container and pour it out, the heat transfer per unit of volume is far faster and the Thermax will set almost instantaneously.

In a production zone or wellbore this means that although it remains liquid in the well bore, away from the wellbore in the immediate periphery- it locks up . So you  can easily perforate past it or, if required, acidize it completely. (15% HCL), These compounds can be engineered to give the time necessary for placement, squeezing (for shut off) etc; by the addition of an inhibitor .

Easy to mix with no special equipment required it can be pumped through the bit. (As approved by Shell Expro . Because Thermax’s setting characteristics  are  absolutely predictable, and it is 100% acid soluble). In contrast cements are not pumped through bits  s they do not have these characteristics. Compressive strengths up to around 10,000 psi are available if required. Strength generation linearly follows the exponential set. Even though it will take a drill string weight Thermax  has the unique property of being easily drilled out. This means in a directional well it can be placed across the build angle in a soft formation, squeezed then drilled out without ‘kicking off.   Utilizing normal rig equipment it requires no special mixing or handling equipment.

It is also totally environmentally safe.

Thermax is specialized into various  compounds for different applications:

Applications are manifold and include;

Remedial operations,

Water shut-off,

Gas shut-off,

Casing leaks,

Formation protection.

Elimination of heavyweight polymer/brine systems in workovers.

Formation consolidation.

Well abandonments.

Lost circulation.

A derivative of Thermax, was developed and US patented by Brian Tomlinson. However, Thermax offers better engineering options and  is chemically different. (It was used to restore full production to Shell’s Gannet platform in the North Sea which was producing only water due to the oil/water interface moving up. The perforations in all eight wells (horizontal) were shut off with only half a barrel of Thermatek using coiled tubing. Completely dry oil, ( 1000+xz bbls/d per well), was the result  after reperforating higher up on all 8 wells).

This was a Worlds first.

Economic Benefits

Thermax offers solutions to many of the downhole problems presently experienced in the upstream industry, plus, considerable cost savings  to the operator over present day methodology and practices.

As present day reservoirs  decline  globally and   the  cost  of discovering, replacing, new production in ever more hostile environments is escalates . So the need to protect both existing and future production is becoming an increasing priority.

Because Thermax can be safely pumped ‘through the bit’ . It can allow huge cost savings in rig time . The need  to pull out of very deep wells in order to remove the bit and run in open ended  can be , for certain operations, eliminated . This operation , especially offshore, can take up to 36 hours with the attendant rig costs.

In drilling exploration wells  cement damage in the production zone can now be eliminated and drilling fluid invasion initially minimized and then eliminated, after placement of Thermax.

In workovers the use, where applicable, of heavyweight, expensive and environmentally damaging, polymerized brines . Can be eliminated together with the need for topside filtration equipment.

This cost-effective technology is not designed to replace the use of oilfield cement, rather it is designed to do what Portland type cements will not do . The unique characteristic of zero gel strength generation together with it’s linear setting characteristic, unaffected by hydrostatics,  provides absolute predictability under varying downhole conditions.

Placing Thermax across the production interval as soon as TD is reached, with or without a slight squeeze, pulling up, reverse circulate and simply wait . Depending on temperature Thermax is very fast. Then simply drill out and run casing and cement as normal. Because Thermax is non-invasive it is easy to perforate past  it, or acidize if required. The production zone is completely protected from cement or other fluid invasion.

In squeeze operations . A major Canadian operator had a problem with gas behind the surface casing. A packer was set and a  high density radial perforation performed. A retainer was set above it . Thermax was displaced and squeezed through the perforations. After a calculated volume had been squeezed externally. Then, because the ONLY concern is temperature, which is known, we knew ‘exactly’ when the set would occur within 120 seconds.

Keeping a very slight squeeze on the Thermax at the set point the squeeze/pump pressure increases almost instantly and the job is done. This is why Thermax can be engineered so precisely.

Thermax has recently been revised completely (US patent and PCT pending), to reflect recent technical and chemical improvements. This includes a unique methodology, developed for a major operator  using Baker Hughes equipment, for utilizing  Thermax to ‘horizontally’  shut-off  the annulus using coiled  tubing. A full scale yard test was conducted using 24” casing inside 30” surface casing. The intial well problem was gas pressure in the annulus between the 24” and 30” casing. The well is full of old drilling fluid of unknown condition. It was not possible to get to bottom due to the centralisers.

Yard Test

7 metres of 24” casing was welded inside 7 metres of 30” casing.

The casings were welded to a bottom plate and erected vertically with scaffolding.

A valve was inserted 2 metres above the base . The annulus between the 24’ and 30” was filled with water based mud. A one inch line was run to 2 metres off bottom with a ‘T’ junction on the end. 2 bbls of Thermax LT, viscosified and lightened to a wt slightly above the drilling fluid. Was displaced horizontally into the drilling fluid in the casing annulus.  Outside temperature was 10C . 24 hour compressive of Thermax was 4000psi. Normal cement was then placed on top of the Thermax.

The casing was taken down and sectioned . The Thermax had displaced the drilling fluid and formed a collar around the 24” casing completely sealing off the annulus.

A photographic record of this event is available  on request.

Costs

Because of the low production costs and the very high technical and economic value of what it does. It is not sold ‘as a product’ but as ‘a technology’. This last is particularly true as Thermax can be engineered to meet different operational problems/requirements.

Thermax offers the opportunity for excellent economic margins  for the technology applier ( Service Company), whilst at the same time providing very high technical and economic value to the operator as a  true ‘solutions’ technology. In many cases it is a ‘negative’ cost to the operator over present day methodology.

A problem ‘solved’ is a cost removed.