EMpulseTM MWD SystemEMpulse electromagnetic measurement-while-drilling (EM MWD)system allows operators to drill and survey wells independentlyof rig hydraulics. Bit pressure drop, flow rates, and drilling fluidand formation loss are irrelevant to EM technology, creatingsubstantial savings in drilling time and project costs. EM MWDsaves an average of two to five days per well due to fastersurvey times and fewer limitations on hydraulics, compared to mud pulse MWD and steering tools.
The EMpulse system has no moving parts, deriving powerfrom long-life batteries instead of a mud-driven generator. The tool propagates an electromagnetic wave along the drillstring to surface, where data is detected and decoded by a surface transceiver. This method allows survey informationto be transmitted regardless of drilling fluid properties.
Electromagnetic surveys do not require extra rig time, unlikemud pulse surveys (which take an average of 3–5 min.) orsteering tools (which take an average of 25 min. to complete a transmission cycle). Once a connection is made, drillingresumes immediately.
EMpulse system is user friendly to drillers because of the system’sability to operate independent of the rig’s circulating system.
Current generation EM MWD transmits real-time data fromdownhole to surface:
Weatherford International Ltd.515 Post Oak Blvd., Suite 600Houston, Texas 77027 USATel: 713-693-4000weatherford.com
• The tool is especially applicable for drilling permeableformations since it is unaffected by drilling fluid loss.
• EM telemetry also is well suited for underbalanced drillingsince it does not require a homogenous fluid column for data transmission.
Applications
Antenna
MWD
MWD
BatteryBattery
Gamma Ray
Gamma Ray
Stinger-mountedconfiguration
Top-hangerconfiguration
Antenna
• Simple, rapid installation at the wellsite.Surface equipment can be installed in lessthan one hour without any modifications to rig equipment.
• Reduced tool inventory/mobilization. EMpulsesystem is a sonde-based design configuredfor use in a full range of non-magneticdrillstring tubulars and hole sizes.
• Two-way communication with the MWD tool.The fundamental advantage of EMpulsesystem is the downlink ability that allowsoperators to communicate instructions to the downhole instrumentation while drilling proceeds. Uplink and downlinkcommunications are completely independentof rig or drilling activity.
• Drillstring optimization. Survey data can be recorded in 15 sec while the drillstring is stationary, which is less than normalconnection time. This reduces the possibilityof differential sticking or hole sloughing thatcan result from extended periods withoutcirculation or pipe movement.
• Reduced survey/connection times. Due to the system’s independence from drillinghydraulics, there is no lag time or need tocycle the pumps for synchronization purposeswhen survey data is being transmitted or tore-sync after anomalous drilling hydraulicsincidents. This also reduces the risk of awashout when transmitting a survey.
• Reduced fishing/lost hole cost. The latestgeneration of EM-MWD allows, in certainbottomhole assembly (BHA) configurations,the ability to wireline-retrieve the EM MWDelectronics.
• Improved reliability. EMpulse system is builtentirely with solid-state electronics designedto operate in harsh drilling environments, suchas air/mist, foam and multiphase underbalancedhorizontal drilling applications.
• Gamma ray measurement. EMpulse systemcan be equipped with a real-time gamma rayprobe. Data is transmitted in real time andalso recorded in downhole memory.
• Annulus pressure. EMpulse system also can beequipped with a real-time annular pressuresensor to measure downhole pressure conditionson any rig while drilling, circulating, monitoringlost circulation or during shut-in conditions.
• GABIS. This short sub can be mounteddirectly above the bit to provide real-timeinclination and gamma ray near the bit.
• Oriented gamma ray. This sensor providesreal-time high-side and low-side gammameasurements while rotating, along with real-time total gamma ray.
MWD/LWD
EMpulseTM MWD System
Weatherford International Ltd.515 Post Oak Blvd., Suite 600Houston, Texas 77027 USATel: 713-693-4000weatherford.com
The sonde- based EMpulseelectromagneticMWD system is easily tested at the rigsite. Simpleinstallation in theBHA minimizestime required on the rig floor.
In low-pressure formations and lost circulation zones, EM MWDsaves significant drilling time compared to steering tools andmud pulse MWD systems.
Average time savings per type of system usedSteering
toolMud pulse
MWD
EM MWD
Average connection time (min) Average survey time (min) Average drilling time (hr/d)
Features, Advantages and Benefits Options
Weatherford products and services are subject to the Company’s standard terms and conditions, available on request or at weatherford.com. For more information contact an authorized Weatherford representative. Unless noted otherwise, trademarks and service marks herein are the property of Weatherford. Specifications are subject to change without notice. Weatherford sells its products and services in accordance with the terms and conditions set forth in the applicable contract between Weatherford and the client.
