3D Inversion Practice For Crosswell Electromagnetic Surveys in Horizontal Wells in Saudi Arabia

A crosswell electromagnetic (known also as DeepLook EM) survey was deployed to map oil and water distribution in a naturally fractured reservoir in Saudi Arabia, between a 1 km long horizontal water injection well and a 1 km long horizontal producer, 1.3 km away. Although high quality data provides a solid foundation for interpretation, 3D inversions of crosswell EM data collected from horizontal wells are very challenging. Many factors can affect the inversion results, especially the starting model and the inversion constraints. This paper reports the process to select and refine the starting models and choose constraints based on existing geological and geophysical information. We also demonstrate the impact of starting models and constraints on the final inverted conductivity structure.