Multivariant Well Placement and Well Drilling Parameters Optimization Methodology. Case Study from Yamal Gas Field

Abstract

More and more oil and gas fields are moving into the third stage of development - the stage of production decline. Oil and gas operating companies are looking for the most effective ways of production stabilization and extending the period of well exploitation. The most frequently used approach of improving exhausted reservoirs performance is reducing the pace of pressure and hydrocarbons production decline by well workovers and horizontal sidetracks drilling. The most widely used type of new producing wells trajectory in low - and medium-amplitude gas fields, which include most of the Western Siberia gas reserves, is horizontal completion. According to the analysis carried out by two major Rosneft scientific centers, in oil saturated reservoirs with thickness less than 20 meters, the efficiency of horizontal wells with 300 meters length is 1.6-4 times higher than for directional wells, depending on the reservoir thickness and permeability. In gas saturated formations, the efficiency of horizontal wells performance relative to the directionally drilled wells in similar geological conditions is 3-6 times higher. As the consequence of scientifically based well performance analysis the volume of horizontal wells drilling and horizontal side track completions at the assets of PJSC "NK "Rosneft" significanty increased as for the period from 2016 to 2021, Figure 1.