While many operators prefer to design relief well (RW) plans using an active magnetic ranging (AMR) tool, it is important to understand the environmental limitations. One common misunderstanding of AMR performance is that the tool is not feasible in highly resistive formations. In fact, ranging at such resistive conditions has a negative impact on the AMR tool detection range; however, ranging operations utilizing AMR can still be achieved by using specific procedures based on different drilling conditions.

The most common type of highly resistive formations encountered in RW design is salt. Salt formations affect the capability of current penetration into the resistive media between a RW and a target well (TW). Without sufficient current, too small of a magnetic field is created on the target well, thus weak or no field to be measured at the AMR tool in the RW.

This paper presents various approaches addressing different types of salt formations to optimize the RW design and ranging plan, as well as reduce the impact of the salt formation on the AMR signal. In such salt formations, the physical formation properties and the corresponding proximity to a planned interception point at the RW will determine the required optimized mitigation techniques Field operators can only attain accurate magnetic ranging measurements for the RW operations using the methods highlighted in this paper.

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