Efficiency analysis of 30-stage fracturing in a horizontal well to oil rims based on through-barrier diagnostics

Abstract

© 2019, Society of Petroleum Engineers Cost-effective reservoir development of oil rims such as Novoportovskoe field requires improving of existing fracturing methods on a way to increase recovery factor. One of the approaches includes the implementation of special completion with renewable fracturing sleeves as well as increasing the number of fracture ports over horizontal wellbore (Belov and others, 2018). This allows to increase profitability from one side, but from the other side, considering the complexity of oil rims geology, this increases the risks of early gas and water breakthrough from the gas cap and water contact respectively via hydraulic fractures induced to untargeted intervals. Generally, the efficiency of implemented well completion design is evaluated based on conventional production logging, however, high resolution and sensitive well diagnostics are required in case of a high number of fracture ports. An additional challenge is associated with diagnostics of flow in the reservoir behind the liner and completion components integrity evaluation such as packer and fracture sleeves. The better diagnostics is applied the more efficient production profile optimization can be done. The paper describes the through-barrier diagnostics concept and shows a case of the performed survey in a horizontal well to oil rim with 30-stage hydraulic fracturing based on through-barrier diagnostics. Two surveys were conducted: the first survey was done at an early stage of well production, then workover was performed based on the first survey results revealing several zones with high GOR and high water cut. The second survey was conducted after the workover. Additionally, the paper describes a novel method on high GOR and high WC zones identification from spectral acoustic data analysis based on machine learning.