GeoSteering in Complex Channel Sand Architecture, a Reality Now with High Definition Deep Directional Multi Boundary Detecting Technology: Case Study From Greater Burgan Field, Kuwait

Abstract

The primary reservoirs in the Greater Burgan Field in Kuwait is the Lower Cretaceous Burgan Sands. Burgan sands are divided into five major units which consist of stacked, massive fluvial channels and some units mostly consist of delta distributary channels and bays in a tidal delta setting grading to shallow marine. These are discontinuous both laterally and vertically. Channel sand geometry in geosteering perspective often sums up to discontinuous patches of sand lenses at differing stratigraphic levels. Maximizing net pay in a channel sand reservoir is known to be a very challenging task for the geosteering domain. Navigating a drainhole through such geometry requires precision geosteering technologies that can map multiple reservoir boundaries with high accuracy enabling precise forward designing wellbore trajectory with respect to the dynamic reservoir geometry. Deep directional distance to boundary "DTB" technology revolutionized the whole concept of geosteering in this regard by enabling proactive geosteering for the first time in industry. Introduced in 2005, it features the capability of detecting reservoir boundaries up to 15ft around the wellbore and achieved great success all over the world through proactive geosteering in thin reservoir layers and maximizing the percentage reservoir contact. However, this technology is limited to mapping only 2 layers, above and below the tool, up to a distance of 15ft around wellbore. It cannot detect a third layer beyond the two layers surrounding it. High definition deep directional multi boundary detecting technology is a noble advancement on the first generation Distance to Boundary technology. With significantly improved signal to noise ratio, supported by a robust and new multilayer stochastic inversion algorithm that incorporates a whole gamut of measurements, principally from 3 firing frequencies (100kHz, 400kHz and 2Mhz), this technology extends its capability by mapping multiple boundaries up to 20ft around the wellbore. This paper examines a case study from the Greater Burgan Field, Kuwait where the extended capability of this technology has yielded exemplary results in navigating wellbores through very complex channel sand geometry with very sharp local dip changes and varying thicknesses. Extreme geosteering is finally made possible with this fit-for-purpose technology in complex subsurface environments, lowering construction risk while maximizing net pay for each well drilled.