A GEOMECHANICAL APPROACH FOR PREDICTING SAND PRODUCTION IN OIL AND GAS WELLS

ABSTRACT

The production of formation sand, is a prevalent problem associated with most oil deposits in the world and predicting or controlling the production of this sand is an even harder problem given the technical, operational and economic challenges associated with it. Majorly, sand production effects affect safety, well or field economics and continuous production and a whole lot more. This has prompted the continued search for solutions to mitigate sand production in the oil and gas industry over time. The control of this formation sand is one of the principal producing problems of oil and gas fields. Predicting whether a well will produce fluids without producing sand has been the goal of many completion engineers and research projects. In order to provide the needed technical support for a sand control strategy, it is necessary to predict the conditions at which sanding might occur. As a result, sand prediction forms the basis for major reservoir development plan. The aim of this study is to predict sand production potentials in a field using a geomechanical approach or Mechanical Earth Model (MEM) which relies on petrophysical log data obtained from a well within the field as input data. Our 1-D MEM utilizes a workflow that develops sand failure mechanisms, first creating the mechanical stratigraphy of the reservoir rock; followed by overburden stress, estimating the pore pressure, rock strength, rock elastic properties, and horizontal stresses of the reservoir rock with reference to the depth of stratigraphic column from compressional slowness, shear slowness, density, porosity and shale volume. These results show the mechanical stratigraphy of unconsolidated sandstone and shale distribution in the reservoir and breakdown pressures, sanding interval analysis, critical drawdown pressure profile and sand failure zones. Based on careful observation of these results, it is therefore possible to predict the wellbore intervals with high sand production potentials within the reservoir formations.