Abstract
With the world's increasing energy demand, it has become more crucial to safely and efficiently maximize recovery from existing assets. In this effort, there are compelling reasons for focusing on clastic reservoirs where horizontal wells are drilled to maximize reservoir contact and drainage area. In this environment, well placement and real-time petrophysical evaluation are the keys to maximizing net- to-gross ratios.
Technology has recently evolved toward the adaptation of a multi-disciplinary approach and integration of real-time answer products to address formation evaluation challenges. To this end, Saudi Aramco has introduced into their lateral operations the slim size LWD spectral gamma ray in combination with the multi-functional logging while drilling (LWD) technology.
By measuring a formation's three naturally occurring radioactive components: potassium (K), uranium (U), and thorium (Th) in real-time, petrophysicists can identify clay mineral types in addition to the standard evaluation. This information allows for more accurate formation evaluation through reliable optimizing petrophysical modeling of mineral and fluid types and volumes. It also minimizes uncertainty on the volume of shale (Vsh) estimation, which has an impact on the effective porosity calculations.
From real-time 16-bin spectral gamma ray data and X-Y magnetometers to track the detectors azimuthal position, a high resolution image is preferred — over the standard gamma ray — for properly identifying target entry and for optimizing well trajectory in clastic formations where the lithology changes vertically and laterally.
