Toe-To-Heel Waterflooding. Part ll: 3D Laboratory Test Results

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA new waterflooding process, Toe-To-Heel Waterflooding (TTHW) was developed, partly based on recently developed thermal toe-to-heel displacement processes: THAI and CAPRI. TTHW is a novel oil recovery process utilizing a horizontal producer (HP) and a vertical injector (VI). The HP has its horizontal leg located at the top of formation, while its toe is close to the VI, which is perforated at the lower part of the formation.TTHW realizes a gravity stable displacement, where water/oil mobility ratio becomes less important, and its detrimental effect on sweep efficiency is diminished. The main advantage of TTHW process is that the water always breaks-through at the toe, following which water cut gradually increases.A systematic investigation of the TTHW process in a Hele Shaw laboratory model mimicking a simulated porous medium showed that the process substantially improved the vertical sweep efficiency as compared to conventional waterflooding. Following these semi-quantitative tests, a more comprehensive 3-D model testing was undertaken in order to investigate the overall sweep efficiency of the process. The 3-D model consists of a metal box filled with glass beads and saturated with oil at connate water saturation; the thickness of "oil layer" is 16 cm and the length is 42 cm. Oil was displaced with a high salinity brine, either in a toe-to-heel configuration, or in a conventional array, using only vertical wells.A staggered line drive was used, by injecting water in two vertical wells located at one side of box and producing oil through either a horizontal producer with its toe close to injection line, or by using a vertical producer located at the horizontal producer's heel position. Several TTHW tests were carried out at different injection rates. For a given injection rate, the TTHW results were compared to those of conventional waterflooding tests. For the same amount of water injected, the ultimate oil recovery increased by a factor of up to two, as compared to that for conventional waterflooding. Numerical simulation models successfully matched the observed performance in the laboratory.All in all, the results of laboratory investigations and numerical simulations show that the novel TTHW process is sound, and can be further optimized.

State of the Art of Western Canadian Heavy Oil Water Flood Technology

“…Turta et al, presented 3 'toe to heel' water flooding papers from 2002 to 2004; advancing from a Hele Shaw model 9 to a 3D lab model 10 , and then to field scale numerical simulation results presented results at the 2004 Annual SPE/DOE Symposium on IOR 11 . Several assumptions listed in these papers likely severely limit the applicability of this technology.…”

Optical measurement of pore scale velocity field inside microporous media

“…A common practice is to replicate the porous media by creating a micro-model of packed sand or glass beads inside a flow cell and to study transport processes by flow visualization techniques (Dawe et al 1992;Turta et al 2003). Santosh et al (2007) used similar flow visualization technique to determine waterflood profiles during oil recovery for horizontal and vertical well configurations.…”

Experimental and Numerical Investigations of Waterflood Profiles with Different Well Configurations

“…Many researchers carried out visualization studies to study important phenomenon such as viscous fingering, etc. Exhaustive literature in this aspect is summarized by Santhosh et al 2 Further, the results of short distance oil displacement (SDOD) experiments using toe-toheel waterflooding (TTHW) 3 using a visual cell have been proved to give satisfactory results with three-dimensional laboratory scale experiments 4 and field scale simulations. 5 Cinar et al 6 performed flow visualization experiments to study the cross flow effects in layered porous media.…”

“…However, none of these have reported the flow patterns with injection and production wells placed inside the visualization pack. Though Turta et al 4 carried out a visualization experiment with wells placed between two plates kept at a distance of 0.01 cm to visualize Hele-Shaw flow, their work does not provide much information about fluid flow patterns. Inspired by their work, this paper presents flow visualization experiments with injection and production wells placed inside porous media contained within a cell.…”