Abstract

The key opportunity of Novoportovskoye Field is hydrocarbon reserves, which remain undeveloped. In this field, significant oil reserves directly underlie massive gas caps. Economic efficiency in such geological conditions is based on the use of new technologies for the maximum extension of field infrastructure loading.

This paper reviews prerequisites and cases of multilateral well drilling technologies as an efficient EOR method at Novoportovskoye Field. The paper summarizes the results of drilling of nine multilateral wells.

The strategy of multilateral well completion at Novoportovskoye Field increased the level of complexity defined by technology advancement for multi-laterals (TAML). First, a multilateral well with an openhole lateral was drilled. This openhole section collapsed when the well was brought into production at the target drawdown. Therefore, the second stage was to construct a multilateral well with cased main bore and lateral using TAML-1 technology.

A version of TAML-1 technology developed by a Russian manufacturer was adapted and implemented at this stage.

Several sidetracking methods were tested to reduce the rig time and multilateral well construction costs. Application of rotary steerable systems (RSS) for sidetracking instead of conventional rotary assemblies and downhole motors enabled to reduce the average sidetracking time from 70 to 30 hours. The record time of sidetracking using RSS was 16 hours.

The history of Novoportovskoye Field development demonstrates a continuous trend towards increasing horizontal section lengths from 1,000 to 1,500 and 2,000 meters. The cumulative multilateral well drilling experience enabled construction of a well with four laterals with a total length of horizontal sections of 4,411 meters. It was the first well with four laterals in Russia built according to TAML-1 technology.

As compared to conventional horizontal wells, the highest initial incremental oil rates were registered in multilateral wells drilled in the Jurassic Yu2-6 interval and the Cretaceous NP2-3 interval of the Novoportovskaya Formation. Considering that the share of the Yu2-6 interval in the oil reserves of Novoportovskoye Field is 46% and the share of the NP2-3 interval is 17%, the operator decided to increase the share of multilateral wells to develop these intervals.

The project objective for 2018 - 2020 is to increase the number of cased holes, to separate laterals to the maximum possible distance, and to improve the completion level to TAML-4.

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