Foam Properties Requirements for Proper Hole Cleaning While Drilling Horizontal Wells in Underbalanced Conditions

摘要

This paper summarizes an extensive experimental programrndeveloped at PETROBRAS R&D Center, as part of the JIPrnnamed “Lightweight Fluid Drilling from Floating Platforms”.rnThe lab work steps include foaming agent selectionrn(considering optimum concentration and salt/oilrncontaminants), rheological characterization of foams,rndevelopment of a flow loop to test foam carrying capacity inrnhigh angle wells, definition of test procedure and matrix,rnbesides discussion and analysis of results. Besides, based onrnresults obtained from a numerical simulator, a comprehensivernand useful model for predicting hole cleaning while drillingrnunder-balanced or near balance with foams is proposed. Afterrnabout 50 bed tests performed in PETROBRAS cuttingsrntransport flow loop, correlations were proposed to predictrncuttings bed erosion capacity in horizontal wells as functionsrnof foam quality. Based on the experiments and on arnmechanistic model for cuttings transport, foam rheology andrnstability requirements for drilling vertical, inclined andrnhorizontal wells in underbalanced and near balance conditionsrnwere established.