Joint inversion of borehole electromagnetic and sonic measurements
نویسندگان
چکیده
New-generation electromagnetic (EM) and sonic logging tools are capable of measuring multi-frequency multi-component data at multiple depths of investigation. This allows us to image the formation around the borehole by using an inversion method. A method is developed for directly obtaining porosity and fluid saturation distributions by simultaneously inverting borehole EM and sonic measurements. This joint inversion reduces the nonuniqueness of determining porosity and fluid saturation distributions, which can not be achieved with either sonic or EM inversion only. We show that the inversion algorithm can accurately obtain porosity and water saturation distributions around the borehole including the zones invaded by the mud filtrate, oil-water contacts, and as well as the dipping structures.
منابع مشابه
A Multiplicative Regularized Gauss-newton Algorithm and Its Application to the Joint Inversion of Induction Logging and Near- Borehole Pressure Measurements
Due to the ill-posed nature of nonlinear inverse problems of borehole geophysics, a parameterization approach is necessary when the available measurement data are limited and measurements are only carried out from sparse transmitter-receiver positions (limited data diversity). A potential remedy is the joint inversion of multiphysics measurements. A parametric inversion approach has desirable a...
متن کاملInversion of surface and borehole gravity with thresholding and density constraints
Minimum-structure inversion has been widely used in both hydrocarbon and mineral exploration for decades. However, models obtained with this method typically exhibit smooth variation of physical properties and smeared-out boundaries, and may not give detailed information about the target being investigated. In this paper we present a constrained joint inversion of surface and borehole gravity t...
متن کاملData-adaptive Resolution Method for the Parametric Three-dimensional Inversion of Triaxial Borehole Electromagnetic Mea- Surements
We develop a new adaptive inversion procedure: Dataadaptive Resolution Inversion (DRI) method, which eliminates the need of selecting a parameterization prior to inversion. Instead, one performs a hierarchical search for the correct parameterization while solving a sequence of inverse problems with an increasing dimension of parameterization. A parsimonious approach to inverse problems usually ...
متن کاملFourier series expansion in a non-orthogonal system of coordinates for the simulation of 3D-DC borehole resistivity measurements
We describe a new method to simulate 3D borehole resistivity measurements at zero frequency (DC). The method combines the use of a Fourier series expansion in a non-orthogonal system of coordinates with an existing 2D goal-oriented higher-order self-adaptive hpfinite element algorithm. The new method is suitable for simulating measurements acquired with borehole logging instruments in deviated ...
متن کاملEffect of borehole stress concentration on compressional wave velocity measurements
Formation elastic properties near a borehole may be altered from their original state due to the stress concentration around the borehole. This could lead to a biased estimation of formation elastic properties measured from sonic logging data. To study the effect of stress concentration around a borehole on sonic logging, we first use an iterative approach, which combines a rock physics model a...
متن کامل