Schlumberger

RADAR Ranging Service

Overview Library

Real-time analysis and advanced ranging

The RADAR real-time analysis of drilling and advanced ranging is a cost-effective solution for well twinning and providing an azimuth in areas of magnetic interference. Our specially trained ranging experts interpret the magnetic interference from nearby wells, employing survey packages from conventional MWD tools. Continuous, real-time measurements during drilling, together with 3D images and well projections, are used to determine the distance and direction of adjacent wells. Borehole trajectories can be accurately placed with quality indicators improving confidence in the results. The operator always has control of the well, and access to the target well is not required during or after drilling. No special downhole tools are required.

Steam-assisted gravity drainage (SAGD) applications

The RADAR service provides an innovative method of drilling SAGD wells that eliminates the traditional well-twinning operation requirement for simultaneous access to both injection and production wells.

The technology allows precise, extremely close positioning of parallel boreholes. In situ thermal extraction processes, such as SAGD, typically require wells to be from 4 to 6 m apart. Our experts run the RADAR service to estimate the distance and position of the injection well with respect to the closest part of the production well. Because this is done continuously in real time during drilling, the well can be placed accurately, avoiding any collision with the production well during the landing process. The service is used to maintain a consistent distance from the target well, with the ability to locally diverge from parallel if necessitated by geological conditions.

Benefits

  • Increases ROP with real-time transmission of data during drilling and no tripping to run a wireline tool
  • Reduces risk by eliminating the need for intervention in, or access to, the target borehole
  • Decreases mobilization time because the MWD equipment is often already on the rig
  • Improves the economics of drilling avoidance and relief wells, as well as injection wells for SAGD applications

MWD survey in areas of magnetic interference applications

The gravity MWD service provides an azimuth in areas of magnetic interference, which traditionally only a gyro-based survey could provide.

The gravity MWD system uses two separate accelerometer packages in the MWD bottomhole assembly (BHA) to provide an azimuth change between the two accelerometers. These measurements are then accumulated to determine the azimuth of the wellbore at any location and in any magnitude of magnetic interference. It is based on simultaneous measurement made with two sets of rigidly connected, tri-axial accelerometer assemblies. In general, two tri-axial accelerometer and magnetometer (survey) packages are deployed in the MWD BHA, allowing the operator to monitor magnetic interference. When magnetic interference is encountered in the wellbore, the system can be switched in real time into gravity MWD mode and then returned to standard MWD mode as soon as the interference is cleared, providing an accurate MWD survey through the entire section.

Benefits

  • No need to rig up and run wireline gyro survey or additional surface equipment
  • No requirement for additional manpower, reducing HSE
  • No risk of stuck pipe during wireline operations
  • Reduced nonproductive time at the rig site

Applications

  • Providing an MWD survey inside or near casing
  • Orientating off a whipstock or cement plug
  • Drilling past a fish or in close proximity to other wells
  • Providing an azimuth in any area of magnetic interference

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