KOPLUS

Koplus LL – Koplus LO

Low to Medium Density Water Based Mud Stuck Pipe Release Agents

Koplus LL – Product Description

• Product: Koplus LL
• Appearance: Clear to pale blue liquid
• Specific Gravity: 1.21
• pH: 1.9 – 2.2
• Supply: Can be supplied in 25-litre, 200- Litre and 1000-Litre containers
• Use: For use in stuck pipe applications in water based drilling fluid systems

Koplus LO – Product Description

• Product: Koplus LO
• Appearance: Clear to pale blue liquid
• Specific Gravity: 1.128
• pH: 1.9 – 2.2
• Supply: Can be supplied in 25-litre, 200- Litre and 1000-Litre containers
• Use: For use in stuck pipe applications in water based and oil based drilling fluid systems – more active in oil coated or glycol environments than Koplus LL

Koplus Chemistry  
Koplus is an extremely effective pipe release agent for water based drilling fluid applications. Used neat, it dissolves polymers, additive carbonates and drilled carbonates while creating a turbulent reaction across the filter cake or well bore face.

The extremely active (and aggressive) ionic environment causes rapid separation of clay particles, drying and subsequent embrittlement. The process allows the transmission of the drill string jarring and pulling action to be transmitted directly to firm, fractured and weakened clay formations, as opposed to soft, plastic and energy absorbing shale.

2.0 The Base Reaction Mechanisms

2.1 Acid decomposition of carbonates & polymers  
Koplus LL's acid base will destroy most drilling fluid polymers in minutes. The same acid base violently reacts with most drilled carbonates, added carbonates and carbonates formed during the drilling process. The dissolution of the polymer base of the drilling fluid filter cake destroys the base integrity of the cake while the carbon dioxide release from the carbonate reaction causes violent near surface turbulence to aid in cake removal.

2.2 Electrolytic Decomposition and Embrittlement Of Clays  
Koplus LL's powerful electrolytic base causes massive base ion exchange within the molecular structure of clays causing rapid dewatering and platelet collapse. Then total shrinkage causes collapse of the filter cake integrity. The drier and shrunken clays transmit the hydraulic power of jarring and pulling much more effectively than the plastic sticky clays nominally causing the stuck situation. In addition to the filter cake effect, cuttings (clay based or carbonate based) are degraded giving the Operator a far greater chance of releasing the pipe. The dehydration and embrittlement of clay structures in conjunction with the polymer and carbonate removal effectively destroys water base filter cakes allowing total fluid and pressure communication between the pipe and the formation – all of which maximise the chance of string recovery.

3.0 Fluids in which to Use Koplus LL and Koplus LO

Koplus LL or Koplus LO can be used in any water-based drilling fluid.

Koplus LL is particularly effective in polymer, salt polymer, polymer glycerol and poly-glycerol mud systems.

Koplus LO is effective in these water-based muds as well as oil-based systems.

4.0 Formations in which Koplus LL or Koplus LO are Effective

Tertiary Clay Formations
In tertiary formations, even in salt inhibited polymer muds, the total reaction time for cake removal is approximately 60 minutes. In dispersed bentonite systems in the same formation reaction time will double to 120 to 140 minutes to total cake dissolution.

Jurassic Clay Formations
Reaction time in Jurassic clay formations is halved (30 minutes to 45 minutes) for all water based mud types.

Carboniferous Formations
Extremely fast reaction times are seen in Carboniferous formations. The reaction times vary from a few (10 to 15) minutes to 35 minutes depending on mud type.

Note**
In all lab simulated verifications, enough fluid (Koplus LL or LO) must be exposed to the cake in order to calculate approximate reaction times. For bench testing purposes, a typical API filter cake of 2/32^nd of an inch can be degraded 45 to 65% in a petri dish volume of Koplus LL.

5.0 Product Usage

Stuck Pipe
Koplus LL and Koplus LO are used neat in pipe release applications. As the product cannot be weighted up due to the foaming tendencies caused by impurities in commercial barites. It is normal to pump a weighted pill ahead of the Koplus LL/LO, if the stuck pipe requires a weight greater than 1.2 SG. The table below gives relative weight requirements for increasing the weight of the mud ahead of the Koplus LLspotting fluid in mud weights in excess of 1.20 SG.

Table 1: Weight Balance

Spotting Volumes
Koplus LL or Koplus LO should be used in adequate quantities to ensure dissolution of the filter cake or formation causing the problem. Volume is very dependent on hole size and the length of BHA to be covered. To cover nominally 400' of BHA (annular volume) for a sixty-minute exposure, with fluid movements every ten to fifteen minutes, the following volumes are recommended.

Table 2: Spotting Fluid Volumes

The volumes above reflect the need to move fluid (pump past ± 1 to 2 bbls) at regular intervals to ensure new, unspent fluid is available for reaction.

Note*
For Koplus LO usage – increase barite quantity by ± 8% to achieve balance

6.0 Effect On Drilling Fluid  

A spacer is not required with Koplus LL between the mud system and the pill. The pH of the mud will drop sharply at the interface of the fluids with carbon dioxide gas generated during the spotting period. Fluid loss in the immediate volumes (1 to 2 barrels) either side of the pill will be elevated. These effects and by-products will be strung out and diluted back in the drilling fluid, when normal circulation commences to some extent. If desirable, fluid on either side of the spotting pill can be dumped or additions of caustic soda and or lime can be made to restore pH values and fluid parameters. It should be kept in mind, incorporation of a 50 bbl pill of Koplus LL in a normal drilling fluid system equates to less than 1.5% by volume or a .25 cc fluid loss increase in a 10 cc API system and a 1 unit pH drop in a 10 pH system of 1500 bbls+.

For Koplus LO used in oil based applications, the fluid effect is similar to any aqueous intrusion into an OBM. The mud system should be pre-treated with light water wetting agents in case the Koplus LO is incorporated into the drilling fluid with the alkalinity adjusted accordingly.

7.0 Stuck Pipe Removal Agent Formulation

Koplus LL should be used neat in all applications, nominally behind a weighted spacer to adjust the hydrostatic column to balance if weights required are above 11.2 ppg. When spotted, the nominal volume is 4 times the annular volume to be covered with the Koplus LL pill moved every fifteen to thirty minutes to move the fluid and carry away spent product as well as cake and formation particles.

8.0 Differentially Stuck Pipe

Koplus LLwhen applied, will rapidly solubilise the filter cake around the drill string in water-based environments. Koplus LL permits pressure transmission to be effectively translated to the steel held in place both from the formation and from the surface.

Used in conjunction with a “U” tube approach, with the Koplus LL formulation calculated to be placed across the face of the target zone at maximum weight reduction, will ensure the greatest chance of success.

9.0 Tight Hole or Sticking Due To Cuttings Bed Build Up

Cuttings beds aggravated by high density barite solids build up during the drilling of high angle wells is a frequent causative agent of stuck pipe.

Koplus LL can be used to remove cuttings due to its ability to specifically dissolve polymers and carbonates which add to the compaction and “smoothing” of the cuttings bed.

Barite sagging during static well bore conditions, creates an ideal situation for the cementation of fine to coarse drill solids by ultra-fine reground barite particles. As the solids settle, they become compacted much in the same manner as filter cake depositions. The resulting hardness and smooth surface, if thick enough, constricts the hole, making wiping difficult with the resulting drag and torque on the drill string. Koplus LL reacts through the build up of barite, removing the cementation effects of formulated drilling fluid additives such as polymers and bridging agents. Once these solids are solubilised the cementation effect is essentially lessened, loosening the solids and releasing them for removal through normal circulating procedures.

Koplus LL should not be used for this application in stable shale formations as the product will destabilise the area immediately around the spot zone. This procedure should only be used in carbonate and sand stone reservoirs.

For these applications, Koplus LL can be temporarily viscosified utilising 2 to 3 ppb of high quality polymers. A pill of viscosified Koplus LL will remain in a high rheological state for approximately 2 hours before decomposing due to temperature, pH, and the activity of the Koplus LL itself.

10.0 Sticking Due To Destabilised Clay Formations and/or Collapsed Clay Formations

Koplus LL is an active and quite aggressive shale destabilising product which utilises excess free potassium ions to force movement of water to and from the collapsed formation and more so through the larger surface area exposed by the collapsed sections of the cuttings, causing the stuck situation. The movement through already destabilised shale further weakens the shale, causing embrittlement, which can be used to the advantage of the drill string during jarring operations.

Koplus LL while removing the cementation effect of the polymers settlement throughout the pack off area of the stuck pipe, is effectively exposing the surface area of the shale as it penetrates the shale platelets causing drying out and embrittlement.

** It should be noted in these situations, the fluid used to drill the hole has not performed its function in stabilising the formation, whether the collapse is due to chemical or mechanical reasons. By adding a destabilising agent to the fluid, one is targeting the collapsed formation around the drill string, which is already inherently unstable in an attempt to recover the BHA and lose as little of the original hole as possible. The resulting size or stability of the hole after the string is recovered is likely to be of little significance in a spotting situation. Whatever caused the formation collapse in the first place will have to be rectified prior to reaming out the original hole or side tracking a new one.

This mechanism of “destructive” chemistry has been successfully utilised in these stuck pipe applications with great success in low to medium weight environments.

11.0 On Board Cuttings Bed, Bit & BHA Balling Removal

In addition to being used as a stuck pipe additive, Koplus LL is applicable for scouring and removal of composites of cuttings beds and barite. It is quite effective (particularly in glycol and polyglcerol inhibited fluids) for breaking and drying out bit and BHA balling.

12.0 Open Hole Pre-Completion Clean Up

Koplus LL can be used to remove filter cake components in sandstone and carbonate reservoirs prior to running screens and gravel packs due to its aggressive filter cake removal qualities.

Koplus LL is used to scour casing prior to completion operations to remove ingrained carbonate, rust and cement films.

13.0 Supply

Koplus LL and Koplus LO are are supplied in 25-litre, 200-litre drums, 1000-litre IBC containers, or in bulk on request.