ESP
ESP is an abbreviation of 'Electrical Submersible Pump'. When a reservoir does not have enough energy to flow naturally, artificial lifting techniques are used to flow the formation fluid to the surface. The most adopted artificial lift method is ESP. An Electrical Submersible Pump houses multiple centrifugal pump stages mounted in series coupled to a submersible electrical motor. This assembly is lowered in the well and is connected to controls at the surface. Multiple stages of ESP connected in a series use impeller and diffuser arrangements to increase the flow pressure. The ESP stages are designed so that after the last stage, fluid attains enough pressure to flow to the surface naturally.
Sand Screen
Sand screens are required for providing sand controls while producing from unconsolidated formations. Sand screens help optimize production, provide wellbore stability and minimize equipment erosion by limiting sand from the formation. Sand screens are classified based on technology, construction, and mesh size. Appropriate sand screens are deployed in the production string depending on well conditions to achieve the best results.
ICD
ICD is an abbreviation for 'Inflow Control Device'. In a lateral where multiple zones are open, it is possible for a high pressure zone to overpower the production flow with very little contribution from low pressure formation. This could deplete the high pressure zone faster and can result in water or gas breakthrough in the well. ICDs are used to balance the hydrocarbon flow from different formations thus helping reservoir and production optimization. In injector wells, ICDs are also used to balance injection pressure across different zones thus improving the production and recovery.
True North
True North refers to geographical north pole of earth and is spatially deviated from the magnetic pole
Trip Gas
Trip gas is the term used to define the gas observed on bottoms up after making a trip. It represents the amount of gas that feeds into the well during the trip while the well is in static condition. Gas feeds into the well due to loss of hydrostatic pressure caused by loss of annular friction pressure or swabbing effect during the trip.
Squeeze Packer
Squeeze packer is used for carrying out squeeze jobs below packer. It is commonly used for remedial cement squeeze jobs. Packer can be set either mechanically or hydraulically. It supports the squeeze pressure and avoids back flow.
Sliding
Sliding is the process of drilling without rotating the drill string. The bit still rotates as it is connected to a motor. Sliding is carried out when attempts are being made to adjust the well trajectory. While drilling a directional well with a motor, the bit is run on a bent sub and hence is at an inclination rather than being vertically down. The bit is oriented in the required direction and is rotated through the motor without rotating the string. This makes it possible to drill ahead with a bit pointing in a specified direction.
Short Drill Collar
Short Drill Collar, also known as Pony Collar is a simply as shorter version of a drill collar. It can be either plain or spiral. Short Drill Collar is used in the string to adjust the spacing between the stabilization points or other tools as needed.
Service Loads
Service Loads in the tubular design represent worst-case axial loading due to all selected burst and collapse service loads as a function of depth along with thermally induced axial strains.
Separation Factor
"Separation Factor" also known as "Error Ratio" is used for assessing the collision risk of two wellbores. It is calculated as a ratio of center-to-center distance and the sum of semi-major axis of error ellipse of the two wellbores. The separation Factor of 1 indicates that the error ellipses of the two well bores touch each other. A separation Factor of less than 1 means that error ellipses overlap and a Separation Factor of more than 1 means that the ellipses don't overlap.
Pony Collar
Pony Collar is simply a shorter version of a drill collar. It can be either plain or spiral. A pony Collar is used in the string to adjust the spacing between the stabilization points or other tools as needed.
Well Abandonment
Well abandonment refers to the process of permanently suspending operations in a well. It is a process of permanently abandoning a well by setting a set of abandonment plugs. Usually, when a well is drilled to the intended target depth and after evaluation, if it is determined that the well will not be completed for production in near future, the well is abandoned. A set of cement and/or mechanical plugs are placed in the well to ensure complete isolation as per regulatory requirements. Every company has its guidelines and policies for well abandonment. The type and number of plugs depend on the type of well and expected reservoir pressure, fluid, etc.
A well can be temporarily suspended as well if it is planned to complete, produce or reenter in the future. Offshore, a Mud Line Suspension (MLS) system is installed to be able to tie back the well in the future once the platform is installed. A corrosion cap is also installed on the top of the well to protect tieback threads and to avoid any debris getting into the well. The Corrosion Cap can be removed and retrieved before tying back the well to the platform.
Non-magnetic Drill Collar
As the name suggests, "Non-Magnetic Drill Collar" is a drill collar made of a non-magnetic material. If magnetic survey instruments are run in the hole, they encounter magnetic interference from regular drill collars which causes errors in measurements of the earth's magnetic field. Hence "Non Magnetic Drill Collars" of sufficient length need to be run as part of the Bottom Hole Assembly for accuracy of survey readings. Non Magnetic Drill Collars are made of austenitic stainless steel and are usually non-spiral.
Multi-lateral Well
Multiple laterals are drilled from one main wellbore. Multi-lateral technology increases reservoir exposure and drainage. It helps reduce the field development cost.
Magnetic North
Earth has got North and South poles but its geographic and magnetic poles do not coincide. The north end of a compass is equivalent to the north end of a magnet, which is attracted to the south end of an external magnet. In our case, the external magnet is the earth’s magnetic field meaning the north end of our compass points towards the earth’s magnetic south pole, which is located near geographic north.
Magnetic Declination
Since 'Magnetic North' and 'True North' do not coincide and refer to two different points on Earth, a correction factor needs to be applied for the readings of the tools that refer to Magnetic North. Magnetic Declination is this correction factor and is defined as the angle between Magnetic North and True North. Magnetic Declination changes with time and location.
Junk Sub
Junk sub is a sub with box-down and pin-up tool joints. A skirt is fitted in the middle portion extending to the box end. This skirt acts as a basket to collect junk that is too heavy to be circulated out. Bleed holes are provided in the skirt for the mud to exit the skirt and return to the circulating system. The junk sub is run directly above the bit.
Jar
The jar is used in the string for generating heavy blows to help release stuck pipes. Jars can be classified as Fishing jars or Drilling jars. They can also be classified based on operating mechanism as Mechanical or Hydraulic Jars. The mechanism inside the jar allows to build up high energy level in the string by way of stretch of slack off weight and makes it release suddenly to create heavy blows.