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Abstract The Pelican Lake heavy oil field located in northern Alberta (Canada) has had a remarkable history since its discovery in the early 1970s. Initial production using vertical wells was poor because of the thin (less than 5m) reservoir formation and high oil viscosity (600 to over 40,000cp). The field began to reach its full potential with the introduction of horizontal drilling and was one of the first fields worldwide to be developed with horizontal wells. Still, with primary recovery less than 10% and several billion barrels of oil in place, the prize for EOR is large. Initially, polymer flooding had not been considered as a viable EOR technology for Pelican Lake due to the high viscosity of the oil, until the idea came of combining it with horizontal wells. A first – unsuccessful – pilot was implemented in 1997 but the lessons drawn from that failure were learnt and a second pilot met with success in 2006. The response to polymer injection in this pilot was excellent, oil rate climbing from 43bopd to over 700bopd and remaining high for over 6 years now; the water-cut has generally remained below 60%. This paper presents the history of the field then focuses on the polymer flooding aspects. It describes the preparation and results of the two polymer flood pilots as well as the extension of the flood to the rest of the field (currently in progress). Polymer flooding has generally been applied in light or medium gravity oil and even today, standard industry screening criteria limit its use to viscosities up to 150cp only. Pelican Lake is the first successful application of polymer flooding in much higher viscosity oil (1,000-2,500cp) and as such, it opens a new avenue for the development of heavy oil resources that are not accessible to thermal methods.
Abstract Very few papers describe waterflood projects in heavy oil reservoirs, and even less that involve the use of horizontal injectors and producers. A few years ago, Beliveau presented a review of waterfloods in viscous oil in several pools mostly in Canada and demonstrated that excellent results can be obtained in most cases, but he mostly focused on pools with vertical wells. The purpose of this paper is to present results of several heavy oil waterfloods in Canada that use horizontal producers and injectors. The production performances of eight heavy oil pools where waterflood has been implemented using horizontal wells have been studied. The pools are thin and bottom water is present in some of them; oil viscosity ranges from a few hundred to a few thousand centipoises. The overall performances of each flood will be discussed and compared to other heavy oil pools where waterflood is implemented with vertical wells. In addition, more detailed analyses will be performed in some patterns to better evaluate the impact of bottom water, well length, spacing and other factors on the flood performances. As could be expected, water breakthrough is generally fast, within a few months from the beginning of injection; but more surprisingly, Water Oil Ratio can often remain stable for long periods of time. Ultimate recovery is expected to vary from a few percents OOIP to over 20%OOIP. Similarly, to waterfloods with vertical wells, a large portion of the reserves can be recovered while producing at high Water Oil Ratio. This paper will present results of several waterfloods in heavy oil reservoirs in Canada which use horizontal wells. There are very few such field cases in the literature thus the information provided will be of interest to engineers who are considering waterflood as a follow-up to primary production in heavy oil reservoirs developed with horizontal wells.
Copyright 2014, Society of Petroleum Engineers This paper was prepared for presentation at the SPE EOR Conference at Oil and Gas West Asia held in Muscat, Oman, 31 March-2 April 2014. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohi bited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright. Abstract Chemical EOR methods such as polymer flooding and ASP (Alkaline-Surfactant-Polymer) are generally not considered suitable for oil viscosities over one or two hundred cp (polymer) or even less (SP/ASP). However this perception is changing, in particular due to field results obtained from a number of chemical EOR pilots or full field floods implemented in Canada in higher viscosity oil in the past few years. Canada is a country well-known for its heavy oil production; recovery processes such as Cold Heavy Oil Production with Sand (CHOPS) and Steam Assisted Gravity Drainage (SAGD) have been invented there. However cold production is limited in terms of the level of recovery it can achieve and thermal techniques also have limitations in particular when reservoirs are thin. Thus Canadian companies have been pursuing chemical EOR to increase recovery in those types of reservoirs. The aim of this paper is to review some of the Canadian projects for which public information is available. Several mostly unpublished projects will be discussed in details, and conclusions will be drawn on the applicability of chemical EOR methods in heavy oil.
COMPLEX WELL ARCHITECTURE, IOR AND HEAVY OILS Gérard Renard and Eric Delamaide, Institut Français du Pétrole, 1 and 4, Avenue de Bois-Préau, Rueil-Malmaison, France; Rob Morgan and Jean-Pierre Fossey, CS Resources Limited, 29th Floor, 645 - 7th Avenue S. W., Calgary, Alberta, T2P 4G8, Canada Abstract. In the last few years, new developments in drilling technology have allowed drilling and casing of multiple lateral wellbores from a single, horizontal or vertical, primary wellbore. Initially, multiple laterals were drilled for primary production to take the laterals cost effectively to the oil, increasing the reservoir exposure (and productivity) and accelerating recovery. Nowadays, these wells are paving the way to new possible complex well pattern architectures. In combination with revisited Improved Oil Recovery (IOR) or Assisted Gravity Drainage (AGD) processes, they can provide economical means to produce a part of the huge reserves of heavy or viscous oils in place all over the world. The general concerns while implementing IOR or AGD processes are: the reservoir conformance (pattern confinement), the sweep eficiencies (area1 and vertical) and problems of injectivity and/or productivity. This paper presents the consequences of using new technologies to gain access to a reservoir in conjunction with well established recovery mechanisms and mobility enhancements to produce low mobility hydrocarbons. Synergy between new well architectures and various processes (IOR or AGD) to improve recovery is presented in detail. Applications to actual field cases are provided to illustrate the potential of this synergy. Finally, specific prob- lems related to multiple lateral wells are outlined. INTRO D U CTIO N The ever-growing interest in heavy oil resources can be easily explained by their size, potential as a future world energy supply, and because geographi- cally they have a strategic distribution in comparison with the distribution of conventional light and medium world oil reserves. World reserves of heavy ["API < 20 (>934 kg/m3)] and extra-heavy ["API < 10 (> 1000 kg/m3), ,u < lo4 mPa - s] crude oils and natural bitumen ["API < 10 (> 1000 kg/m3), ,u > lo4 mPa . s] are estimated' to about 100 Giga- tonnes (GT). Major reserves are located in Canada, Venezuela and Former Soviet Union (Fig. i). Canada's natural bitumen reserves are mainly in the Athabasca region. The FSU natural bitumen resources are concentrated in the Volga-Ural and East Siberia. Venezuela has most of its heavy oil and bitumen in the Orinoco Belt. The cumulative pro- duction as of today is close to only 7 GT (Fig. i), with a major part produced by Venezuela and U.S.A. While these reserves are approximately equal to the identified reserves of conventional crude oil accredited to the Middle East' (96 GT), their contri- bution to the world supply is low, less than 5%. Until recently, this could be explained by the fact that unconventional r
Summary The Pelican Lake heavy-oil field in northern Alberta (Canada) has had a remarkable history since its discovery in the early 1970s. Initial production by use of vertical wells was poor because of the thin (less than 5 m) reservoir formation and high oil viscosity (800–80,000-plus cp). The field began to reach its full potential with the introduction of horizontal drilling and was one of the first fields worldwide to be developed with horizontal wells. However, with primary recovery at less than 10% and 6.4 billion bbl of oil in place (OIP), the prize for enhanced oil recovery (EOR) is large. Initially, polymer flooding had not been considered as a viable EOR technology for Pelican Lake because of the high viscosity of the oil, until the idea came of combining it with horizontal wells. A first—unsuccessful—pilot was implemented in 1997, but the lessons drawn from that failure were learned and a second pilot was met with success in 2006. The response to polymer injection in this pilot was excellent, with oil rate increasing from 43 BOPD to more than 700 BOPD and remaining high for more than 6 years; the water cut has generally remained at less than 60%. Incremental recovery over primary production is variable but can reach as high as 25% of oil originally in place (OOIP) in places. This paper presents the history of the field and then focuses on the polymer-flooding aspects. It describes the preparation and results of the two polymer-flood pilots, as well as the extension of the flood to the rest of the field (currently in progress). Polymer flooding has generally been applied in light- or medium-gravity oil, and even currently, standard industry-screening criteria limit its use to viscosities up to 150 cp only. Pelican Lake is the first successful application of polymer flooding in much-higher-viscosity oil (more than 1,200 cp), and as such, it opens a new avenue for the development of heavy-oil resources that are not accessible by thermal methods.