Gilsonite can be used as an addictive in drilling mud. Gilsonite is a pure natural hydrocarbon with the melting point of 160 to 220 degrees which is found naturally in mines and in fact it's hardened petroleum. As it has a common oil base, it can easily be mixed with petroleum-based bitumen. When mixed, gilsonite and bitumen particles become so close and form a mixture which both has the resistance and durability of Gilsonite and also the flexibility of bitumen. Having high amount of nitrogen compounds, Gilsonite has high level of cohesion and also increases the resistance against oxidation. Low level of sulfuric content also increases the quality of the final product. Research has shown that adding 5 to 15 percent MD to the bitumen results in noticeable increase in solidity and resistance against deformation, without any significant effect on viscosity and cohesion. Cohesion, filling and connection properties of Gilsonite can avoid number of different damages. Also, it can create an effective coverage to prevent drilling liquids from penetrating inside the cracks by creating a physical and chemical bond with porous formations. As the only substance which can have both formation and sealing properties, application of gilsonite in drilling mud avoids fluid's leak and waste, and protects the well's surface from damages caused by heat or drill's rotation. HP/HT wells, shale, and under pressure areas are in need of specific drilling liquids and specialized equipment and techniques. Adding gilsonite or natural bitumen to OBM or WBM in the following ways is involved in well reinforcement :
- Reduction of pore pressure transmission and filling of micro-cracks in shale and low porous sands.
- Make an impervious cake filter on the well walls to avoid collapse
- Form a permanent protective layer all along the wall of the well
- Protection and maintenance of different layers of well wall
Gilsonite's effect on drilling mud can be pointed out in where this material can cover the impervious parts of the well and avoid any further damages to the drilling tools and also prevent the vulnerability of the measurement devices even in areas with high differential pressure difference and the fluidity of cake filters.
Benefits of Using Gilsonite as Drilling Mud Addictive
The following is some of the benefits of using gilsonite as drilling mud addictive:
- Minimize damage to the stored energy stored in the ground
- Cooling, lubrication, drilling tools and drill heads
- Transfer of hydraulic energy to tools and drills
- Ensure adequate and correct evaluation
- Facilitate cementing and finishing work
- Slow down the adverse effects on the environment
- Prevent the formation of gaseous hydrates
- Column and filling of permeable formations
- Waste out of the well
- Formation pressure control
- Suspend waste
- Ensuring well stability
- Corrosion control
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