Experimental Fireflood in a Very Viscous Oil-Unconsolidated Sand Reservoir, S.E. Pauls Valley Field, Oklahoma

Abstract

This field produces 8000 cp 100 API oil by natural water drive from an unconsolidated sand reservoir about 100 feet thick. Nearly all wells produced 10–50% sand initially, declining later to 0.1–2%, regardless of completion method. Apparently this production of sand created inter-connecting "worm hole" porosity extending at least between wells on porosity extending at least between wells on 10-acre spacing. Some of the evidence for this during primary production was:near-gauge caliper surveys of open hole sections after production of large volumes of sand;rapid movement of injected water and tracers between wells; andproduction of Jelflake lost circulation material from two wells following its use in workover and deepening of a third well. Air was injected below the oil-water contact in an edge well as a partial test for spontaneous ignition in a peripheral fireflood. In about four months some offset wells were converted to flowing after breakthrough of "air" devoid of oxygen but also containing very little carbon dioxide. When produced "air" reached high oxygen containing test was stopped. Later a structurally high 'Well was ignited. Extremely rapid travel of carbon dioxide to 2 offset wells was also indicative of inter-connected "worm hole" porosity created by production of sand. The fireflood stimulated two offset wells such that total field production increased from 100- to 170 BOPD previously to a maximum 400 BOPD six months later and averaged 310 BOPD for the 16 months of air injection. Cumulative average air-oil ratio was 6 Mcf/bbl. Although the test was physically successful, abnormally high physically successful, abnormally high producing well operating expense precluded producing well operating expense precluded continuing operation and expansion of the project. project Introduction The Southeast Pauls Valley Field, Garvin County, Oklahoma, producing from the oil Creek Sand at a depth of 4300 feet, 'Was discovered in March, 1955. Since it produces very viscous oil from unconsolidated sand, operating problems have been severe.

Production froide des huiles visqueuses. Première partie : Observations sur champ

“…Un article (Elkins, Morton et Blackwell, 1972), le premier dans la littérature qui semble mentionner la possible existence de wormholes au sein du milieu poreux, a trait au champ de Elk Creek en Oklahoma (USA).…”

“…La première publication suggérant l'existence de chenaux de haute perméabilité date de 1972 (Elkins, Morton et Blackwell, 1972). Dans cette référence, une injection de traceur dans un puits a été observée dans un puits voisin distant de 120 m après 52 h (2,64 m/h).…”

Modelling of Sand Production From Wells On Primary Recovery

“…Several heavy oil producers (1)(2)(3)(4)(5) have recognized that producing sand with oil significantly enhances primary recovery. The widespread use of progressive cavity pumps has been a key factor in making the Cold Production process economical by reducing the damage to wells caused by the pumping of sand.…”

“…The widespread use of progressive cavity pumps has been a key factor in making the Cold Production process economical by reducing the damage to wells caused by the pumping of sand. Elkins et al ( 1 ) were among the first to suggest that high permeability channels, which they called wormholes, develop in oil formations when sand is also produced. The wells were located in the Southeast Pauls Valley Field, Gavin County, Oklahoma.…”

“…All investigators report the production of large quantities of sand: 700 m 3 (Elkins et al ( 1 ) ), 580 m 3 (McCaffrey and B o w m a n ( 3 ) ), 500 m 3 ( Y e u n g ( 7 ) ), and 560 m 3 (Metwally and S o l a n k i ( 5 ) ). These investigators all report high sand cuts at the start of cold production: 10% to 50% (by volume) during one month (Elkins et al ( 1 ) ) , 30% to 40% during two weeks (McCaffrey and Bowman (3) ), 20% to 30% (Yeung (7) ).…”