| Popis: |
The North Slope of Alaska has billions of barrels of heavy original oil in place (OOIP) residing in largely undeveloped reservoirs. Despite this large volume of heavy oil in place, the majority of reserves development on the slope to date has been focused on light crude. However over the past few years, operators have begun to develop the North Slope's vast heavy oil resource base. Recently, an optimum drill-in-fluid/formation damage minimization study was undertaken by ConocoPhillips, BP, and its partners in order to determine the optimum reservoir drilling fluid for the heavy oil sands in order to maximize well productivity and project value. This paper will provide an in-depth look at the drilling fluid design, laboratory testing, and productivity analysis associated with determining the optimum reservoir drill in fluid (RDF) for the West Sak, horizontal, multi-lateral, extended reach, field development. Lab test results to be reviewed will include: Crude Compatibility Lubricity (steel to steel & rock to steel) Shale Stability General Rheology Mud Filtrate invasion tests with core to determine Return Perm Filtercake Removal tests w/ceramic disk tests to determine return permeability and removal effectiveness With the lab test results, well productivity calculations will illustrate why an oil based mud (OBM) was determined to be the optimum drill-in-fluid for West Sak. Lab tests and inflow performance modeling show injectivity and productivity improvements associated with reducing water based filtrate invasion and permeability reduction due to water and ineffective filtercake removal. Results show that the overall process of integrating the drill-in-fluid, completion design, inflow performance modeling, and operations procedures should be considered a best practice and an example of how an integrated study ultimately provides a field development with the best project value. Using the current field development economic model, this process added reserves, improved project NPV & IRR and maximized project economics |
