Solids Control & Waste Management
Solids Control and Waste Management is the process of managing, treating and disposing of waste generate during the drilling a well in particular cuttings and drilling fluid (mud). Depending on the mud system used waste generated can be highly toxic. Appropriate Solids Control and Waste Management practices can significantly lower the amount of waste and its toxicity as well as the negative effects waste can have on the well and down-hole equipment.
In general, the waste management strategy is stage ladder process, whereby reducing the waste at its source is the first option, followed by recycling, and finally treatment and disposal. The subcategory consists of two major areas:
1) Solids collection and control
2) Waste Treatment and Disposal.
SOLIDS COLLECTION AND CONTROL – is a process of separating solid rock particles in the mud generated by drilling, cleaning the mud, and recovering the mud before returning it back to the system. Depending on the application and mud system used, solids collection and control equipment is comprised of:
Mud Tanks – mud storage and mixing
Shale Shaker – separates big solids, as a first stage separation
Desander – separates medium sized solids
Desilter – separates small sized solids
Mud Cleaner – a combination of desander and desilter
Vacuum degasser – separates the air from the mud
Conveyance System (auger) – transports cuttings on the rig, normally offshore
Decanter Centrifuge – high-speed & variable-speed centrifuges are required when drilling fluids requires further processing to provide higher mud recovery rate and comply with stricter environmental standards. Decanter centrifuge can also recover up to 90% of barite that can be re-used.
Mud Cooler – to cool the drilling fluid, mostly used in oil-based mud and high temperature applications
Cutting dryer – ideally vertical, this device reduces liquid content in cuttings to below the 5% mark. Shakers, mud cleaners and centrifuges would leave cuttings with a liquid content on between 10% to 15%.
Dewatering Unit – allows removal of the fine solids (less than 5 microns) from the water based drilling fluids, using chemical processes.
Cuttings collection & transportation system – is a closed loop system providing vacuum or pneumatic powered conveyance to transport cuttings for a relatively long distance, e.g. from an offshore drilling rig to a supply vessel.
Drill Cutting Boxes are small open containers / skips that are used to transport cuttings from drilling rig offshore, to the shore base for further treatment and disposal. Depending on the drilling speed, solid equipment on the rig and distance to shore, the number of skips ranges from 150 to 350 per rig.
WASTE TREATMENT AND DISPOSAL is the process of management and disposal of waste generated by drilling fluid and drill cuttings, after the solids collection and control phase. Depending on the mud system used and initial treatment, the water content in cuttings and its toxicity may still be high and further treatment could be required, prior to final disposal. This stage is not always present and there are instances when non-toxic waste is disposed immediately. Oil-based mud and synthetic-based mud are considered to be toxic and must go through a treatment and disposal process. There are various options to treat and dispose the waste and the selection criteria are driven by regulations, costs, type of waste, and what equipment is available. The options available are:
Cuttings Re-injection (CRI) is used for re-injecting drill cuttings back to the reservoir through separate disposal wells, old non-producing wells or existing production wells. This process returns drill cuttings to its native environment and does not produce any pollution. This is the only on-site, permanent disposal method that is in full compliance with environment standards. In certain applications, cuttings re-injection is a more cost-effective solution,
Thermal desorption is a process of indirectly heating the waste to increase volatility of contaminants that frees them from solids matrix and evaporates them from the cuttings. This in turn removes oil and other toxic materials from the processed cuttings and provides less than 0.1% of oil-on-cuttings content, to allow further disposal (landfill and land farming) Two major types of technology are used:
1) Thermomechanical, whereby friction is the source of heat and
2) Thermal Phase Separation,
The table below shows the various attributes and characteristics of available cuttings management strategies
IMPROVE FRACTURING FLUIDS, IMPROVE RESULTS
Fracturing Fluid Systems
Sama Al Dalw creates a wide variety of well stimulation additives for hydraulic fracturing that improve safety and reduce environmental impact. Our offerings include high-performance materials designed to maximize your well productivity and decrease costs. We offer synthesis and formulation expertise, as well as total fluid designs, including custom additives. Because water’s unique characteristics can make or break an operation, we will analyze your frac water to guide product development and selection, and we will diagnose any ancillary issues related to water quality, such as bacteria, hardness or scaling tendencies. Additionally, we assure compatibility between all additives and optimize all components, including crosslinkers and breakers, for the ultimate in performance