A Workflow to Estimate Critical Drawdown Pressure Utilizing 1-D Geomechanics Modelling

Abstract

The active mobility of sand particles during the production phase has put extra burden on the efficiency of hydrocarbon extraction for both oil and gas. It plays a significant role on completion design during the drilling phase. Minimizing the effect of sanding has been a major topic to tackle due to the added operational costs and time associated. Unconsolidated sand reservoirs are vastly affected worldwide due to the nature of sand particles accompanying hydrocarbon during the production phase. Sand production poses potential risks for surface and subsurface equipment within the completion design. The objective of this paper is to estimate and quantify the potentials of sand production and wellbore instability using 1-D Mechanical Earth Model (MEM). A clear workflow of the utility of raw petrophysical and 1-D geomechanics modelling data is showcased to aid production and completion operational personnel. Excessive stress concentrated around the wall of a borehole can cause the release of sand particles into the hydrocarbon stream. This process poses risks for drilling and completion operations as it affects the productivity of a well along with potential equipment damage. Unconsolidated sand reservoirs are prone to rock failure which induces the mobility of sand particles. Stress orientation regimes are properly captured by assessing the orientation of current petrophysical data. Acoustic data is also reviewed for proper in-situ rock strength property calculation. Formation pressure testing is vital to the process to estimate pore pressure gradients. Once MEM is finalized, Critical Drawdown Pressure (CDDP) is analytically calculated using the linear elastic methodology to predict sand production. The use of 1-D MEM sand management analysis to predict critical drawdown pressure is vital to avoid equipment damage and production limitations associated with sand production in a weakly consolidated reservoir. A workflow to produce an in-depth critical drawdown pressure analysis captures the changes that might occur for a perforation completion over time as it undergoes depletion. A representation of sand potential prediction and critical bottom-hole flowing pressure as a function of reservoir pressure is to be illustrated in a single depth format which allows for sensitivity analysis. This paper examines the direct impact of the analytical estimation of critical drawdown pressure as a guide to predict the potentials of sand production intervals within a certain reservoir. The mechanical properties, petrophysical raw data, and depletion status are the ingredients to produce a thorough analysis to guide drilling, production, and completion personnel to minimize sand production effects operationally. Further improvement to the model can be made by the integration of production data and reservoir properties that are captured over time.