Industry, working through organizations like the American Petroleum Institute (API), has a long history of developing consensus based ‘best practices’ or standard procedure. These standard best practices are developed by industry in a variety of area of technology and operations and go through rigorous operations before being adopted. They are then evaluated to incorporate evolving technology and operational practices.
Protecting Groundwater and the Environment
All oil and natural gas exploration, development, and production operations are conducted to ensure that the environment, in particular underground sources of drinking water (USDWs a, or groundwater), is protected. Statutes and regulations have been implemented in every oil and gas producing state of the United States to ensure that oil and natural gas operations are conducted in an environmentally responsible fashion.
is periodically tested to ensure its integrity is maintained. The monitoring activities are conducted prior to and during well construction and over the life of the well.
Well Design and Construction
Drilling and completing an oil and/or gas well consists of several sequential activities. These are addressed in this guidance document are shown in sequential order, these activities are as follows:
- building the location and installing fluid handling equipment,
- setting up the drilling rig and ancillary equipment and testing all equipment.
Drilling the hole, logging the hole, cementing the casing, logging the casing, removing the drilling rig and ancillary equipment, perforating the casing , hydraulic fracturing or stimulating the well, installing artificial lift equipment (if necessary), install surface production equipment, putting the well on production, monitoring well performance and integrity.
The well design ensure the environmentally sound, safe production of hydrocarbons by containing them inside the well, protecting groundwater resources, isolating the productive formations from other formations, and by proper execution of hydraulic fractures and other stimulation operations. The well design and construction must ensure no leaks occur through or between any casing strings. The fluids produced from the well (oil, water, and gas) must travel directly from the producing zone to the surface inside the well conduit.
The Drilling and Completion Process
Drilling a typical oil or gas well consists of several cycles of drilling, running casing (steel pipe for well construction), and cementing the casing in place to ensure isolation. In each cycle, steel casing is installed in sequentially smallersizes inside the previous installed casing string. The last cycle of the well construction is well completion, which caninclude perforating and hydraulic fracturing or other stimulation techniques depending on the well type.
The design and selection of the casing is of utmost importance. The casing must be able to withstand the various compressive, tensional, and bending forces that are exerted while running in the hole, as well as the collapse and burst pressures that it might be subjected to during different phases of the well’s life. Design of the steel casing strings is a key part of the well design and a key factor in well success, including assurance of zonal isolation and wellbore integrity.
Casing is threaded on each end, and has a coupling installed to join it to the next pipe. When several joints of casing have been screwed together they form a continuous ‘string’ of casing that will isolate the hole. When screwing together a casing connection, applying the proper amount of torque is important. Too much torque overstresses the connection and can result in failure of the connection. Too little torque can result in a leaky connection.
Oilfield cements are engineered products that are covered by API technical specifications, recommended practices, and technical reports. The cements and cement additives selected and the cementing practices utilized are an integral part of sound well design, construction, and well integrity. Various cements and cement additives are available for use. Appropriate API standards should be consulted in the selection and use of cementing products.