North Slope Heavy-Oil Sand-Control Strategy: Detailed Case Study of Sand Production Predictions and Field Measurements for Alaskan Heavy-Oil Multilateral Field Developments

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe North Slope of Alaska has billions of barrels of heavy oil residing in largely undeveloped reservoirs. Despite this large volume of heavy oil in place, the majority of reserves development on the slope to date has been focused on light crude. However over the past 20 years Arco, BP, Conoco and now ConocoPhillips have begun to develop the North Slope's vast heavy oil resource base. Recently a sand/solids control study was undertaken by ConocoPhillips and BP in order to determine the most economic strategy for solids control and well design in future heavy oil developments.The study was integrated across companies, organizations and discipline boundaries in order to include completion, rock mechanics, laboratory research, drilling, reservoir, geological, operations, facilities and field personnel. With this diverse team, actual solids production and solids predictions were investigated from a number of different perspectives. Solids production predictions were made based on core measurements, log analysis, simulators that predict formation failure and sand production rate, laboratory core flow tests, 2 years of field shakeout data, and multiple field measurements of solids production. Probabilistic predictions were then generated based on these investigations rather than deterministic "best guesses" for the economic analysis. These different methods for predicting solids production will be discussed and illustrated in this case study.The study and ensuing strategy determined that sand management or using non-sand exclusion slotted liners and sand tolerant facilities was the highest value development scenario over the life cycle of the North Slope Heavy Oil Developments.

Prediction of Wellbore Stability Using 3D Finite Element Model in a Shallow Unconsolidated Heavy-Oil Sand in a Kuwait Field

“…This was achieved using Mohr Coulomb shear failure criterion applied to available triaxial tests data. Similar results have been reported for heavy oil sands elsewhere in the literature (Vasquez et al, 1999;Burton et al, 2005). 3) effective confining pressure in F1B sand exhibiting shear failure at 10% axial strain was used as a basis for this approach.…”

Environmental Challenges of Heavy Crude Oils: Management of Liquid Wastes

“…The Gran Field in the Norwegian Sector of the North Sea uses a combination of water-injection (waterflood) and gas pressurization and lift to produce heavy oil (19ºAPI) from a low pressure reservoir at a depth of 1700 m below the seabed in a water depth of 128 m (4). Water alternating with gas (WAG) is being evaluated for production of the less viscous heavy crude oils from the West Sak and Schrader Bluff formations on the North Slope of Alaska, where the largest untapped heavy oil resource in the United States is located (5). Cyclic steam stimulation (CSS), sometimes called huff and puff, has been used for many years in Canada, Venezuela, and elsewhere to enhance recovery of conventional and moderate viscosity heavy crude oil from the formation (6,7).…”

Coupled Reservoir and Geomechanical Modeling of Sand Production in Waterflooding of Heavy Oil Reservoirs

“…There are 7 to 15 billion of barrels of oil in place (Burton et al, 2005) and hundreds of millions of barrels potentially recoverable. The less viscous of the heavy oil sands are currently being produced from the Orion and Polaris reservoirs in the Greater Prudhoe Bay Unit and also at the adjacent West Sak and Milne Point reservoirs.…”

“…Geomechanical modelling has been identified as a method to improve the economics of the North Slope heavy oil production. In a parametric study by a coupled reservoir/geomechanics simulator, the authors have attempted to analyze the influence of different (Burton et al, 2005) operational controls in water flooding operations in order to mitigate the MBE occurrence and the respective production impact.…”

“…The producing wells are generally horizontal with slotted liner completion. The slotted liner allows some sand production but has better economics due to higher productivity and lower well costs than a sand control completion (Burton et al, 2005).…”