Effects of Drilling Fluid Waste on Soil Properties
The exploration and extraction of oil industrially and economically began in the mid-nineteenth century. Hundreds of years ago, this natural source was used for lighting purposes or as a lubricant.
The invention of the first internal combustion engine and its use in all forms of life today has led to an increase in demand for the extraction and exploitation of fossil fuels. The positive and negative consequences of the expansion of these activities in the oil industry, which is done in order to meet the bulk of energy supply, is an issue that has always been faced by those in charge of this industry.
Reducing the environmental impact of this section requires the analysis of complex issues that require a proper answer due to its direct relationship with the quality of human life.
The following are general answers to these questions:
Identify waste generating activities
Investigating the potential impact of waste generated on the environment
Understanding the mechanisms and routes of waste transfer and the distribution of pollutants
Study of effective ways in waste and pollutant management
Applying purification methods to reduce the volume and toxicity of materials
Optimization of evacuation methods
Cleaning contaminated environments
Sources of drilling waste
In the upstream oil and gas industries, there are two major types of operations that can affect the environment. Drilling and exploitation, both of which bring significant amounts of waste into the environment. Measures to understand how to produce such waste and how to distribute it are among the main needs. With such knowledge and the use of methods to improve operations, the resulting damage can be minimized and even completely eliminated in some cases.
Excavation involves a series of operations in which a hole is made in the ground to direct underground hydrocarbons to the surface. An average of one hundred wells are used to drill each oil tank and several thousand barrels contaminated with various substances harmful to the environment are used to drill each well. These materials are released into the ground after use. Evidently, one of the main sources of environmental pollution in drilling operations is directly related to fluids and compounds that are used as drilling mud. In addition, large amounts of fragments of subsurface formations, saline water in the lower layers of the earth and petroleum hydrocarbons are transferred to the earth’s surface during this process.
The effect of drilling fluids on soil properties
Drilling fluid is a water or oil-based compound that, along with additives, plays effective roles in drilling operations. These include maintaining the pressure of the well and preventing it from erupting, maintaining the strength of the well wall (formation), transferring cuttings to the ground surface, cooling and lubrication of the drilling bit, etc. During drilling operations, the consumed and waste fluids along with other materials are transferred into large pits. At the end of the drilling process, the wells are left in the same way as before, often without a repair process.
Due to the direct contact of these materials with the soil, this environment undergoes chemical, physical and biological changes. Identifying the trend of these changes requires methods that can be used to better determine the distribution of these materials at spatial distances and determine the extent and scope of their effect.
The most common method for discharging drilling fluids involves directing these materials to the mud pits that are constructed in the vicinity of the drilling rig. The area of these pits can reach several thousand square meters depending on the duration of drilling and its type. These materials and chemicals remain in the pits and their volume will decrease over time due to infiltration into the subsoil or evaporation.
Such materials and chemicals are unloaded using the spraying method performed by tanker trucks. This method is one of the expensive methods that are used in areas where it is not possible to build drainage pits (especially in mountainous areas).
In this method, the tankers after unload their cargo after loading and during the distance while moving in a predetermined place. Re-injection of these materials into the underground layers is one of the appropriate methods to remove these contaminants. The re-injection process should be done taking into account the non-contamination of aquifers.
Environmental effects of drilling rigs
Drilling rigs are generally made of low density particles and in addition to causing environmental problems, generally have an adverse effect on the properties of drilling mud. Drilling mud and rigs are inevitable toxic by-products in drilling. Drilling rigs make up about 10% of the volume of drilling waste. During the drilling process, hazardous fluids and drilling rigs combine with oil, water and other chemicals to form a toxic drilling mix. This mixture contains toxic chemicals such as oil, phenol suspension solids, arsenic, chromium, cadmium, lead, mercury, natural radioactive materials and barium materials. These compounds vary depending on the location of the well, the depth of the well and the type of used drilling fluids and cement.
The amount of solid drilling cuts decreases as the diameter of the well decreases. Drilling rigs that are the result of drilling operations for oil and gas wells contain large amounts of drilling mud that contain oil compounds and are harmful to the environment. Some of these damages include disruption of the soil’s biological activities, toxic effects on plants, and harmful effects on humans due to the entry of substances into the food chain.
Environmental effects of heavy metals in drilling mud
Heavy metals enter drilling fluids in two ways. Many metals are naturally present at the drilling site and therefore enter the fluid used during drilling. Some metals are added to the drilling mud as an additive to create the desired properties. For example, Barium and Mercury in Barite as a density controller are sources of heavy metals in crude oil drilling fluid. Crude oil naturally contains very different concentrations of different metals. Metals in crude oil include: aluminum, calcium, chromium cobalt, copper, gold, iron, lead, magnesium, manganese, nickel, phosphorus, platinum, silicon, silver, sodium, strontium, uranium, tin and boron. Nickel and vanadium have the highest concentrations.
Environmental effects on human health
Weakness, anorexia, bronchitis, periodic neurological diseases, skin diseases, gastrointestinal problems and damage to the liver, heart, nerves and kidneys
Weakness, fatigue, anorexia and indigestion, severe tremors in severe high-level contacts
Barium ion in some cases causes stroke and paralysis in living organisms
Kidney damage, bone cracks, kidney stones, osteoporosis, shortness of breath and pain in the head and joints
Severe irritation of the respiratory system, respiratory problems and kidney damage
At high concentrations it causes inflammation, damage to the heart and digestive system, as well as damage to the liver and kidneys.
Brain injury, seizures, mental disorders and death
skin allergies and allergic reactions
Effect on eyes and respiratory system in more severe contact Damage to lung, liver, kidneys and heart
Harmful effects of high concentrations on the lungs
In order to protect the environment and the ecosystem, the environment must be prevented from being polluted. The first step to achieving this is to prevent the production of pollution as much as possible. In some industrial activities such as drilling, pollution is inevitable. In such cases, one should minimize the amount and try to recycle or reuse it. In cases where these environmental activities cannot be implemented, these wastes will inevitably enter the environment.
To reduce the amount of pollution, wastes must be refined, and wastes that do not cause significant damage to the environment are discharged into the environment (environmental standards and regulations determine whether the pollution is harmful). Contaminating waste is either eliminated by chemical or biochemical processes or inevitably buried, which must be done with the utmost care in accordance with the standard. This section discusses the four activities in order to protect the environment and comply with environmental laws.
Prevention of waste generation
The easiest way to protect the environment is to prevent the formation of contaminating waste, which is achieved by reducing the volume or amount of pollution. For this purpose, the following measures are provided:
Replacement of process and products that can reduce the volume and amount of waste contamination. Modify the process and use more efficient mechanical equipment, improve drilling techniques such as the using effective drills to reduce the use of chemical additives and ultimately reduce pollution.
– Complete consumption of chemicals and return unused materials to the seller.
Revival & Recycling
After examining the ways to reduce contaminants, in this stage, strategies for recycling and reuse of waste will be studied.
Return to process and reuse
If possible, burn to produce energy
Reuse in other processes or recycling to reuse in other industries
Treatment of drilling fluids wastewater
Due to the destructive and long-term effects of drilling wastes into the sea and their negative effects on marine ecosystems, governments, industries and organizations working on the environment are looking for ways to reduce the volume of drilling effluents. One method of this is to re-inject the effluents into the seabed or, if possible, to treat them. In 1995, the American Petroleum Institute explored various methods for treating drilling wastes. In the published reports, the pollutants that affect the toxicity of the waste were announced as follows:
Very fine suspended particles, salinity above 90%, volatile compounds, extractable organic matter, ammonia solution and vapors and hydrogen sulfide.
In API reports, reducing effluent pollution to an acceptable level through a combination of different methods has been proposed. In choosing the wastewater treatment method, cost estimation is necessary and is one of the influential factors in determining the treatment method. Table 3 shows the different methods of treatment of drilling effluents.
Sama Karimi is chemical engineer, drilling fluids specialist and product manager. She’s is involved in technical aspect of chemical export project at TEAM. Her effective communication skills made her to be our contact person for many reigns.
She is chemical engineer, and drilling fluids specialist at TEAM. Before that she was a drilling fluid engineer for 3 years. In this role, she was responsible to work on new type of drilling fluids additives and specialty chemicals along with managing a team of two drilling fluids production expert. Her efforts and success in this role helped to reduce waste and general costs of mud production projects.
She is graduated from Farzangan High School and entered the chemical field at Iran University of Sciences and Technology.
Corrosion is a natural affinity for metals to return to compounds before reduction. Oxygen corrosion in drilling industry is one of the most important factors in the destruction of metal pipes and equipment. Metals in nature are often in the form of compounds that are thermodynamically stable, lose their stability after reduction, and if they are again in close proximity to the natural environment, they are corroded and return to their original composition.
Corrosion is divided into wet and dry types. The wet corrosion mechanism is electrochemical. However, the dry corrosion is called solid-gas reactions at high temperatures. In the drilling industry wet corrosion is more common.
Corrosion of iron in drilling mud and other fluids are the other types of corrosion in drilling industry. The high electrical conductivity of fluid causes flow current and corrosion rate to increase.
Drilling mud can be considered as the most important factor in the drilling process. Any problem in the production of drilling mud or mud circulation system will stop drilling operations and result in heavy fines. Proper selection of mud circulation system is effective in preventing possible breakdowns and reducing downtime. This systems are made of different parts, which will be introduced in the following.
Drilling mud problems may be due to mud composition or the mud circulating system selection. The composition of added materials to the mud is determined depending on the drilling conditions, formation structure, drilling depth etc. For example, Hematite is added to the drilling mud composition in high pressure wells to control the pressure caused by the formation. It is clear that the selection of materials to be add to the mud requires special expertise. But in this article, without considering the composition of drilling mud, the systems used to circulate the mud in drilling are examined.
Introduction:The oil and gas industry is one of the largest and most important industries in the world, which is very important strategically and economically. With the development of environmental solutions in human societies, activities that endanger the environmental system will be seriously considered. For this reason, efforts have been made to reduce the environmental impact of drilling operations, especially in the use of drilling fluids. In this article, the management of green drilling fluid supply chain is investigated. First, the management of the green supply chain and related literature and the role of drilling fluids in the drilling process of oil and gas wells and the environmental effects of these materials if they are not controlled and monitored are stated. Then the management of green supply chain of drilling fluids is examined.