Glossary
Downhole Motor
Conventional drilling operations rotate the drill bit by turning the entire drill string at surface. A downhole motor simply utilizes the rig's circulation system and the hydraulic power of the drilling fluid to rotate the adjacent drill bit without the associated energy losses of the drill string interaction with the wellbore. |
Drilling Fluid
Fluid circulated through the wellbore during drilling operations to cool the drill bit, remove rock cuttings, prevent the borehole walls from caving in and constrain high pressure formation fluids. In a liquid, non-aerated state, the drilling fluid or "mud" enables the transmission of hydraulic pressure pulses from a downhole Measurement While Drilling (MWD) device to the surface. |
Dynamic Data Management (DDM)
Also known as Well Site Data Management (WDM). Electronically recording, processing and presenting surface and downhole information produced while drilling oil and natural gas wells. The oil and natural gas clients use this information on a real-time basis during drilling at the rig site or later for analysis. This information is often accessible on a real-time basis through a direct data connection or on a daily basis via the Internet. |
Dynamic Pressure Device-2 (DPD-2)
Ryan's Dynamic Pressure Device-2 (DPD-2) provides real-time annular and internal bore pressure information, which enables the determination of drilling fluid Equivalent Circulating Density (ECD). The DPD tool is powered by lithium batteries enabling its use either for monitoring downhole pressure during tripping or for leak-off tests, which determines the maximum pressure the open hole formation can sustain without fracturing or losing circulation. The tool has no moving parts and is equipped with its own memory to store data. |
Electromagnetic (EM) Communication Technology
EM communication technology utilizes low frequency radio waves, rather than traditional hydraulic pulse telemetry, to transmit data from downhole to the surface. Ryan's EM communication technology is unique in that it can be used during conventional, underbalanced, horizontal and directional drilling operations and is fully retrievable and re-seatable. |
Equivalent Circulating Density (ECD)
This is the drilling fluid density that would be required to produce the same effective borehole pressure resulting from the combination of fluid density, circulatory pressure and cuttings loading of the drilling fluid in the wellbore. |
Gamma Steering Instrument (GSI)
Ryan's Gamma Steering Instrument (GSI) uses an advanced processing of sensor data combined with an oriented "window" through which natural gamma ray formation measurements are recorded. This focusing technique allows the operator to monitor formation changes adjacent to the borehole, enabling the operators to adjust the well path and optimize its position in the zone of interest. |
Horizontal and Directional Drilling
Refers to intentionally drilling a non-vertical wellbore at a closely controlled, predetermined angle and direction through the use of special downhole equipment. Such well bores may initially be vertical, but are deviated to reach a specific target or to expose the wellbore to a larger portion of the reservoir. |
Hydrostatic Pressure
The pressure exerted by the density of drilling fluids in the wellbore. |
Logging While Drilling (LWD)
Refers to the technology that records (logs) characteristics while drilling. This information provides the client with more accurate real-time information about the surrounding geology, leading to more informed decisions on well path trajectory and reservoir characteristics. |
Measured Depth (MD)
The actual distance measured along the axis of the borehole from the zero depth reference point to the depth of interest. |
Measurement While Drilling (MWD)
Refers to a technique of making downhole measurements of borehole position, toolface orientation, formation parameters and drilling information using sensors located in the bottom hole assembly adjacent to the drill bit. These measurements are made during drilling and can be recorded downhole and/or transmitted to surface. |
Pulse Telemetry System
Pulse telemetry is a method by which information is communicated from the wellbore to the surface. The MWD downhole device creates encoded hydraulic pressure pulses. The information is then converted into an electrical signal at surface and decoded. |
Total Depth (TVD)
Typically the measured depth to the bottom of the wellbore. |
True Vertical Depth (TVD)
The vertical distance from a reference elevation to a subsurface point of interest. |
Underbalanced Drilling
The process of drilling a well with a fluid column exerting less pressure than is exerted by the reservoir fluids. This process is often performed using gases (eg. nitrogen) to reduce the density of the drilling fluid column. |
Well Site Data Management (WDM) System
Electronically recording, processing and correlating surface and downhole information produced while drilling oil and natural gas wells. The oil and natural gas clients use this information on a real-time basis during drilling at the rig site or for post drilling analysis. With the RigWatch system, information can also be accessible on a real-time basis through a direct data connection or on a daily basis via the Internet. |
