Gilsonite Cementing

What is Gilsonite Cementing?

Gilsonite Cementing is an extremely important operation in oil well drilling to ensure the integrity of the well and prevent gas and oil migration for an extended period of time. Failure to have adequate cementing will lead to problems that are often catastrophic. Many times, a revisit of cement integrity is required to diagnose any issues such as the formation of micro-fractures that will cause fluid or gas migration into the wellbore or to the surface.

One of the primary functions of Gilsonite in cementing is to control fluid loss. When cement slurry is pumped into a wellbore, it can lose water to the surrounding formation, which can lead to incomplete cement placement and reduced zonal isolation. Gilsonite helps create a more impermeable filter cake on the wellbore walls, reducing fluid loss and ensuring better zonal isolation.

General Description of Gilsonite Cementing

Gilsonite cementing is known for its high-temperature stability. It can maintain its properties and integrity at elevated temperatures, making it suitable for Gilsonite cementing operations in high-temperature wells where other additives may break down or lose effectiveness. also, Gilsonite can act as a rheological modifier, helping to control the viscosity and flow properties of the cement slurry. This is important for achieving proper placement of the cement and ensuring that it flows effectively downhole.

Gilsonite can contribute to enhanced cement compressive strength. This is crucial for ensuring the long-term integrity of the wellbore and preventing issues such as cement sheath failure. Gilsonite can contribute to enhanced cement compressive strength. This is crucial for ensuring the long-term integrity of the wellbore and preventing issues such as cement sheath failure.

Oil and gas well-cementing additives are a highly developed technology. Cement-water slurries, with or without various additives, have been used for many years in cementing procedures carried out from time to time during the drilling of the productive life of a well. Cementing is often applied during drilling and completion procedures in connection with the protection of production zones, isolation and confinement of water zones, support of borehole wall, anchorage of the casing, and control of lost circulation not overcome by methods associated with the circulation of drilling mud. Such cementing procedures by cementing additives are ordinarily regarded as being of the primary character.

Gilsonite in Oil Well Cementing Advantages

1. Fluid Loss Control: Gilsonite is highly effective in controlling fluid loss during cementing operations. It forms a tight and impermeable filter cake on the wellbore walls, reducing the loss of cement slurry into permeable formations. This helps ensure proper zonal isolation and wellbore integrity.
2. Temperature Stability: Gilsonite is known for its exceptional thermal stability. It can maintain its properties and structural integrity even at high temperatures, which is crucial for cementing operations in wells with elevated temperature conditions. This stability prevents the breakdown of the cement slurry.
3. Improved Rheological Properties: Gilsonite acts as a rheological modifier, allowing for better control of the cement slurry’s viscosity and flow properties. This ensures that the slurry flows effectively and can be placed accurately in the wellbore.
4. Enhanced Compressive Strength: Gilsonite-based additives contribute to the development of higher compressive strength in the cement. This increased strength is essential for maintaining long-term wellbore integrity, preventing issues such as cement sheath failure, and ensuring zonal isolation.

Cementing Additive

Since Gilsonite, a solid hydrocarbon, was introduced to the oil industry in August 1957 as a cement additive, several thousands of jobs have been performed using the material. These operations have included primary cementing through lost-circulation zones of surface, intermediate, and production pipe in both single and multiple stages as well as various remedial jobs such as squeezing, re-cementing above inadequate fill-up, and plugging back to reestablish drilling-fluid circulation.

Designed primarily as a combination of low-density lost-circulation slurry, Gilsonite has yielded excellent results in areas of incompetent formations as well as in other types of lost-circulation zones. Field results generally show that fill-up of 80 to 90 percent can be obtained in areas where only 50 to 60 percent fill-up was possible with other types of slurries.

The unique properties of Gilsonite such as low specific gravity, particle-size distribution, impermeability, resistance to corrosive fluids, chemical inertness, and low water requirements result in a slurry having exceptional bridging properties, low slurry weight, compatibility with other slurry additives, and relatively high compressive strength when compared to other slurries of the same weight.

Cementing additives should be realized that there are various classes with respect to melting points. The lower the melting point, the faster the gilsonite will dissolve in a solvent therefore or soften under conditions of heat. Therefore, the use of gilsonite in an oil and gas well-cementing composition affords an opportunity to select a class of that material that best serves the particular purpose. The heat softening characteristic of gilsonite becomes of particular importance in instances of relatively high bottom-hole temperatures, where there is a tendency for the additive to soften and diffuse into the surrounding cement.

The blending of Gilsonite cementing additives with other drilling mud additives increase performance in cementing and drilling fluids in a way no other single additive, the recognized industry standard for filtration control, is equally effective at controlling lost circulation and improving wellbore stability.

The unique properties of Gilsonite cementing such as low specific gravity, particle-size distribution, impermeability, resistance to corrosive fluids, chemical inertness, and low water requirements result in a slurry having exceptional bridging properties, low slurry weight, compatibility with other slurry additives, and relatively high compressive strength when compared to other slurries of the same weight.

Gilsonite Properties that Create the Ideal Cement Additive:

• Low specific gravity (1.04–06 @ 77 °F)
• High softening points (>340 °F)
• Semi–Polymeric behavior
• Low moisture content (<5%)
• Does not impact thickening time
• Hard to fuse (no re–massing)
• Compatible with paraffin, Resins, Oils, Asphalts, and Elastomers
• Compatible with other cement additives
• High purity

Cement Slurry

Conditions are often encountered in the field requiring various combinations of particle size and particle size distribution. The above examples represent extremes. The mix must, however, always be pumpable through the system from the mixing point to the final point of placement of the cement slurry. The coarser the aggregate, the less that may be present in any given slurry without impeding pump ability.

Cement Slurry Benefits:

• Increases yield
• Reduces slurry weight
• Controls free water
• Lowers slurry water ratio
• Promotes favorable rheologies resulting in lower ECDs
• Prevents lost circulation
• Scours wellbore/enhances mud removal
• Cost-effective
• Consistent quality
• Multipurpose

The Role of Gilsonite Cementing

As the oil-producing industry has continued to grow, the need for a low-density cementing slurry possessing lost-circulation control characteristics has become more and more evident.. This is especially so In primary cementing because of the different types of formations being encountered and the need to reduce remedial cementing operation These problem formations may range from either porous or cavernous formations to very weak formations that are unable to support the hydrostatic head that is necessary for drilling and well completion. This latter type of formation will often break down or fracture under hydrostatic loading, resulting In a partial or complete loss of circulation.

Lost-circulation zones encountered during drilling operations may produce many problems In the normal course of completing a well. Increased expenditures can result from reduced drilling finishing jobs, and other mechanical difficulties as well as from loss of large volumes of drilling fluid. Sometimes severe lost-circulation problems may even cause abandonment of a well. Lost circulation during cementing operations will often be reflected by inadequate fill-up In the annulus and the consequent displacement of slurry into formations away from the well bore. Satisfactory isolation of the different formations may then require re-cementing work above the point of loss and subsequent squeeze-cementing jobs.

For more than 50 years, the industry has depended on Gilsonite as a lost circulation material and a critical component for primary cementing operations in some of the world’s toughest drilling environments. Gilsonite is a special type of solid hydrocarbon(asphaltite) used with cement to reduce slurry weight and minimize lost circulation.

Gilsonite is used in cementing slurries to provide density control, scouring action for mud removal, and support compressive strength development. It has a unique reaction with shale that improves cement bond development and strength. The wellbore is the primary hole on which the final well will be made.

Also, wellbores can be encased by steel or cement or in some cases, depending on the situation, may not be encased. In oil wells, it is necessary to encase the wellbore with cement. Adding the Gilsonite material during oil well cementing enhances the isolation characteristics while decreasing the vertiginous Gas flows. These characteristics can result in more effective mud removal which also enhances the environmental factors. Drilling environmental regulations are getting more and stricter around the world.

Gilsonite cementing grade used for oil and gas well

Gilsonite Cementing Grade is an effective ingredient in insulation and it would be recyclable in the environmental cycling, reducing the risk of environmental damage to a very high level. Today, following the very fundamental challenges of insulating deep wells during drilling, due to the use of a variety of chemicals to insulate the walls of the well, these chemicals are very harmful to the environment, which is why the environment’s supporters Have lived.

For many years, the drilling industry has used Gilsonite Cementing Grade as a basic and recyclable medium in the worst parts of the world to cement the walls of oil wells. Using Gilsonite as an additive during the operation of wall cementing of oil wells the biggest advantage will be that the Gilsonite will prevent the spread of gas and hydrocarbon to the environment.

Specification of Gilsonite Cementing