A well selection method of CO₂ huff and puff in heavy oil reservoir with edge and bottom water based on water cut

¹ The Unconventional Oil and Gas Institute, China University of Petroleum, 18 Fuxue Road, Changping, Beijing 102249, China
² The School of Petroleum Engineering, China University of Petroleum, 18 Fuxue Road, Changping, Beijing 102249, China

^* Corresponding author: ltjcup@cup.edu.cn

Abstract

The water cut of heavy oil reservoir with edge and bottom water rises rapidly and the recovery degree of crude oil is low. CO₂ huff and puff is an effective measure to improve the recovery of this kind of reservoir, and scientific well selection is the premise of the measure effect. Because the existing well selection methods of CO₂ huff and puff in heavy oil reservoir with edge and bottom water mostly take the oil increase of oil well as the evaluation index, ignoring the characterization of well water cut after huff and puff, it is unable to accurately screen all potential wells. Therefore, a quantitative well selection method of CO₂ huff and puff in heavy oil reservoir with edge and bottom water based on water cut is proposed. The method is based on fuzzy comprehensive evaluation theory and analytic hierarchy process, and takes the water cut after CO₂ huff and puff as the evaluation index. Several groups of typical models are designed to screen the sensitive factors and laws of CO₂ huff and puff well selection in heavy oil edge and bottom water reservoir from three aspects of geology, water production law and technology. Than the judgment matrix is established. There is little interference from human factors in the process of well selection, and the rationality of the method has been verified by the effect of field actual well measures. This method is helpful to improve the well selection method system of CO₂ huff and puff in this kind of reservoir, and is a reasonable supplement to the existing well selection method which takes the oil increment as the only evaluation index.