Importance of Drilling Chemicals
Drilling activities play a vital role in oil and gas exploration and production. Drilling companies utilize a variety of chemicals to ensure smooth functioning of drilling operations. From drilling mud additive, cementing chemicals to cleaning chemicals, drilling chemicals are indispensable part of drilling operations. However, improper handling and storage of these chemicals can lead to environmental and health hazards. Therefore, it is important understand the applications of drilling chemicals and handle them with care.
Drilling Mud Additives
Drilling mud plays a pivotal role during drilling operations. It helps in lubricating and cooling the drill bit, carrying drill cuttings to surface, controlling well pressure etc. But plain water or oil based mud alone cannot serve all these purposes. Drilling engineers add various chemicals known as drilling mud additives to enhance desirable properties of drilling mud. Some key drilling mud additives are:
Weight materials like barite are added to increase mud density for well control. Lighter weight materials like calcium carbonate reduce mud density. Viscosifiers like bentonite, guar gum and polymers are used to control fluid loss and increase viscosity for better suspension of cuttings. Compounds like PH control agents, shale inhibitors, fluid loss controllers add stability to mud system. Surfactants reduce surface or interfacial tension between mud and formation fluids. Biocides prevent microbial damage to mud system.
Cementing Chemicals
Cementing is an essential well construction process where cement slurry is pumped into well annulus to isolate and support well structures. Cement additives optimize various properties of cement slurry depending on downhole conditions and well design requirements. Some key cement additives are:
Gas block additives minimize migration of gas within cement and prevent formation of channels. Retarders delay setting time of cement for proper placement. Fluid loss additives control fluid loss from cement slurry into formation. Accelerators quickly set cement when required. Dispersants improve particle distribution in slurry. Flexibilizers add flexibility to cement to avoid cracking due cracks induced by pressure, thermal or mechanical effects. Strength retrogressants lower compressive strength to minimize risk of fracturing formation by cement during curing.
Completion and Workover Fluids
Special formulations are required during completion, stimulation and workover operations which involve fluid movement inside production tubing or holes. Some special chemicals are:
Acid inhibitors protects pipe from damage by acid during acidizing. Viscosifiers enhances viscosity of fluid system for proper transport/placement of proppants, services or chemicals. Friction reducers minimize friction pressure for smooth fluid movement. Shale control agents stabilize shale formations. Clay control chemicals alleviate damage by swelling and migration of clays. Surfactants aid in fluid recovery and cleanup after jobs. Biocides control bacterial growth affecting fluid properties. Scale inhibitors prevents scale deposition inside production tubing or holes.
Chemicals for Secondary Operations
Oilfield chemicals have applications beyond drilling and cementing in various secondary operations including production enhancement, workovers, pipeline chemical treatments and corrosion inhibition:
Production chemical like paraffin dispersants and scale inhibitors maintain well integrity and enhance production. Corrosion inhibitors form passive film over internal surface of pipes, tubulars, and equipment protecting them from corrosion. Defoamers and demulsifiers aid in separation of oil, gas and water during production. Scale removal chemicals dissolve existing scale deposits improving flow. Biocides kill bacterial growth in reservoirs, wellbores and surface facilities. Scale inhibitors prevent precipitation of metal salts like calcium carbonate.Paraffin control chemicals keep paraffin solids in suspension avoiding plugging inside casing or tubing.Hydrate inhibitors maintain stability of gas hydrates at appropriate conditions.
Proper handling and disposal
While drilling chemicals improve operational efficiency, improper handling can impact both people and environment adversely if not handled carefully. Some best practices for safe handling include:
-Store chemicals as per MSDS guidelines in a secure warehouse away from habitation or water bodies.
-Provide necessary PPE like gloves, goggles, boots and overalls to workers while mixing, handling or transportation of chemicals.
-Recycle or dispose empty containers as per regulatory guidelines.
-Treat and dispose waste chemicals, cuttings and used fluids through authorized waste management companies following standard procedures.
-Monitor chemical seepage or contamination in soil or water resources near oilfield operations.
-Perform regular health checkups of workforce exposed to chemicals.
-Adopt green substitutes wherever viable options are available.
-Conduct regular safety trainings for workforce on chemical storage, transportation and operations.
Various drilling, cementing and completion chemicals play pivotal role in oilfield operations. However, they require cautious handling following best practices to balance operational and environmental safety. Adopting alternative green substitutes wherever feasible can further strengthen responsible resource development. Overall, judicious use of drilling chemicals optimizes efficiency while minimizing risks to people and environment.
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