METHOD FOR EXTRACTING LAYER-ZONE-WISE HETEROGENEOUS FORMATION OF HIGHLY VISCOUS OIL OR BITUMEN Russian patent published in 2007 - IPC E21B43/24 

FIELD: oil industry, possible use during extraction of layer-wise and zone-wise heterogeneous formation of highly viscous oil or bitumen.

SUBSTANCE: product multi-mouth horizontal well is built with additional side boreholes passing below argillaceous seam. Above the extracting two-mouth horizontal well, in parallel to it, force two-mouth horizontal well is built with ascending additional branching boreholes, which are driven through argillaceous seam in ascending manner. Penetrability zone is created between wells due to forcing of water heat carrier into both wells. After creation of penetrability zone, heat carrier is fed only into force multi-mouth horizontal well, and product is extracted from product multi-mouth horizontal well. Dryness degree of forced steam (gas fatness) is periodically alternated. Firstly, steam with low dryness degree (large gas fatness) is forced in to increase pickup of force multi-mouth horizontal well and share of incidental water in extracted product, and then high dryness degree steam is forced in (low fatness gas), volume of which is determined on basis of forcing pressure increase, which is maintained at level not exceeding the vertical crack opening pressure. Product is extracted via product multi-mouth horizontal well until full extraction of productive formation. When limited area argillaceous seams are present, in accordance to invention, from horizontal borehole of product well, additional side boreholes are driven in ascending manner through argillaceous seam, vertical wells are additionally drilled, passing through argillaceous seam, while vertical wells are used as transport channel for filtration of steam (gas) above the location of argillaceous seam and creation of steam (gas) of oil pool, and also as means for moving extracted product downwards.

EFFECT: increased speed of warming, increased coverage of bed across area and vertical, increased oil yield and decreased energy costs of thermal effect induction process.

3 cl, 1 tbl, 1 ex, 1 dwg