Conductivity Enhancement and Productivity Restoration of Deep North Kuwait Jurassic Gas-Condensate Well by Using Effective HRMA Stimulation Technique

摘要

Achieving sustainable gas and condensate production from carbonaceous North Kuwait Jurassic Gas (NKJG) reservoirs has been challenging due to multi-dimensional inflow/outflow complications under restrictive operating downhole conditions. Production from the NKJG reservoirs has strategic importance for the State of Kuwait, where the formations are deep and sour, and produce gas-condensate and volatile oil, in which the produced fluids contain from 2 to 8% H2S and 1 to 3% CO2. High reservoir pressure of up to 12,000 psi is widespread trapped below an over-pressured salt structure. NKJG reservoirs have high temperature of ~275°F and have been recently completed with monobore completions, to optimize overall commingled well performance and to ensure operational optimization of future well interventions. Differential depletion has had significant consequences in well and reservoir management including the design and execution of stimulation treatments, particularly the “high rate matrix acidizing (HRMA)” applications. In addition, vertical variations in lithological and mechanical rock properties contribute to drilling challenges which are progressively exacerbated as the deepest zones continue to produce most of the hydrocarbons whereas other potential horizons are not exploited at similar rates. Monobore completions have been deployed so that each flow unit could be segregated and stimulated separately, starting from the bottom, moving uphole as each stage is treated, activated, tested and isolated using drillable bridge plugs. After all zones are completed, the bridge plugs are drilled out using coiled tubing mills and commingled production is established from all zones.