Innovative solutions in construction of deep industrial brine, oil and gas wells in deformable fractured reservoirs

Abstract

The paper deals with the methodological features of drilling and completion of wells in the fractured natural reservoirs containing oil and gas accumulations with different reservoir pressures of fluid-pressure systems from abnormally high to abnormally low. The authors had studied the fluid-pressure systems of industrial lithium-bromine brines, oil and gas fields and accumulations in the south of the Siberian platform for the period from 1983 to 2019. The article summarizes the main results, including new technical solutions protected by the Russian Federation patents. The authors proposed and patented a series of new technical solutions for the immediate consolidation of natural permeable fractures during the primary opening of the reservoir by drilling, as applied to a fractured reservoir. The main task of the study is to preserve the permeability of the fractured system in the bottomhole formation zone under the action of compressive stresses (rock mass) that increase with the formation of a drawdown cone, primarily in the bottomhole formation zone with the increase in the drawdown (ΔP) above critical values. Such an area is the bottomhole formation zone within a radius of the first meters around the well that penetrated the fractured reservoir. Practice has proved that the use of innovative solutions through the advanced consolidation of permeable fractures in the bottomhole formation zone (of fluid-producing oil- and gas-bearing, water-bearing reservoir) in the open (initial natural) state ensures the preservation of natural permeability of natural filtering fractures of the reservoir with the fluid system reservoir pressure from anomalously low to abnormally high. The solution ensures constant permeability of the fractured filtration system throughout the cleaning cycles of the bottomhole formation zone rocks from drilling mud, obtaining of the true calculated hydrodynamic parameters based on the results of well testing in the modes of the “steady-state production method” and well flow rate (productivity) stabilization under further well operation.