Abstract

Application of proper technologies in the heavy and extra-heavy oil field of the Orinoco Oil Belt of Venezuela has led to significant improvements in oil production during the last 30 years. However, the many cold production methods tested in the area have achieved a maximum recovery of only 20%. Increasing the recovery factor remains a priority for the oil industry and has led to the testing of hot production methods, such as steam-assisted gravity drainage (SAGD).

SAGD uses two parallel horizontal wells, one drilled above the other, with continuous steam injection to achieve recovery efficiencies up to 60% in many heavy and extra-heavy oil fields worldwide. Magnetic ranging technologies are used to maintain precise separation along the trajectory of the two wells, which is critical for the effectiveness of SAGD technique. If the horizontal wells are too close, the steam will rapidly migrate to the production well. If there is excessive separation, gravity drainage will not occur.

A national Venezuelan operator determined that SAGD technology is applicable in the San Tome area of the Orinoco heavy-oil Belt and proposed to drill a pair of SAGD wells in the U1, 3 MFB-53 reservoirs to evaluate the effectiveness of the technology to recover an additional 2 MMBB. Increasing the recovery factor to 38% in the area affected by injection with a rate of 1,500 BNPD and holding it for 3 years will determine the success of the technique in the Orinoco Oil Belt.

This publication will describe the characteristics and production history of the Bare Reservoir, as well as the implementation of SAGD drilling techniques in the development of related fields. Specifically addressed will be how the precise pre-planning and execution of the separation and alignment between the two existing wells was achieved using active magnetic-ranging technology. Finally, production results will be presented and explained.

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