Abstract

In 1984 Redford1 published a paper with a similar title which outlined 60 years of field experience in recovering bitumen from Athabasca by in situ methods, commented on what had been achieved and outlined the more promising recovery processes for different geological ettings.

This paper covers the period from 1984 to the present. It outlines and discusses the eight field pilots which have been conducted since then or were not completely reported in the first paper. These are: The Texaco Horizontal Well Project, The Canterra Kearl Lake Project, The Gregoire ake In Situ Pilot, PCEJ Stoney Mountain Electrical Preheat Project, PCEJ Hangingstone Steam Stimulation Pilots, UTF HASDrive Pilot, Steepbank HASDrive Pilot and UTF SAGD Pilots. The potential for in situ recovery from thabasca is discussed taking into account the experience gained over the last 70 years. The aper concludes with some observations on the tatus of developing in situ recovery from Athabasca and where future progress is needed.

Introduction

The Athabasca oil sands deposit in many ways is the jewel in the crown of oil sand deposits. Its huge reserves and its thick pays with high porosity, permeability and bitumen saturations have made it a tempting target. Yet 10 years ago, 60 years of extensive experimentation both in the field and the laboratory had not yielded a commercial process and only one technically successful field pilot. 10 years ago it could be said that we had learned to ask the right questions but did not yet have the right answers.

A lot has changed in the past 10 years. The technology base laid down in earlier years has born fruit and we have seen the completion of several successful pilots and the demonstration of one technology which promises the dream of those early pioneers - low cost, reliable in situ bitumen recovery from Athabasca, This paper outlines the field experience over those last 10 years, discuses it and comments on where we stand.

Texaco Athabasca Horizontal Well Project

In 1980 Texaco, using a slant rig, drilled three horizontal wells in shallow oil sands (overburden 72 metres, pay 63 metres) at their pilot site south of the Fort McMurray airport. These wells Figure 1) had about 400 metres of horizontal section located near the base of the deposit and were completed open hole with a 0.76 mm keystone slotted sand exclusion liner. A production tubing extended approximately half way down the horizontal section. The project was supported in the late stages by the Alberta Oil Sands Technology and Research Authority (AOSTRA) which has now been merged into the Oil Sands and Research Division (OSRD) of the lberta Department of Energy.

The recovery concept tested was similar to that used in the Petro-Canada MAISP project2,3 with steam stimulation of the outside wells followed by steam drive from the centre well to he two outside wells.

The pilot experienced severe difficulties from the start due to two of the major reasons for pilot failure in Athabasca; reservoir heterogeneity and sand exclusion.

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