It is important to note that heavy oil-producing sand’s lithology and grain size are not entirely continuous along its length, as i. It may be influenced by shale intercalations or non-permeable formations that impede the constant flow of oil towards the drainage radius of the well. Now, effective thermal stimulation in wells subjected to steam injection depends on the thermal chamber’s optimal distribution and displacement along the entire net oil sand section. For this, it is of utmost importance to perform a detailed analysis of the petrophysical properties of the reservoir or study area and thus determine the optimal injection points in the most prospective zones with high porosity and permeability values.
THERMAL COMPLETION FOR SELECTIVE STEAM INJECTION
According to previous studies of temperature monitoring in horizontal wells with steam injection in heavy oil reservoirs, heat is not evenly distributed along the producing section. At Nakasawa Resources, we have paid particular attention to the well completion (injector/producer) design to ensure an efficient sweep of the steam chamber and thus improve well productivity.
To achieve this, it is essential to position the injection points in the most prospective zones by installing a system consisting of high thermal insulation pipes, zone separator packings with expansion joints, and steam distribution valves.
The valves can be operated mechanically or hydraulically. The degree of opening will depend on the percentage distribution of steam along the entire producing section to guarantee an efficient sweep and a greater delivery of calorific power to the reservoir.
With this innovative design, we enlarge the thermal chamber and improve the wells’ productivity in percentage values exceeding 300% of additional crude produced.
The increase of the recovery factor in tertiary recovery processes of heavy crude oil depends mainly on optimizing extraction techniques. In the case of steam injection, the uniform sweep of the producing zone will guarantee the increase of oil production by delivering a higher calorific power to the reservoir.
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