Refining Geology W ith the Bit: An Innovative Approach to Well Design and Geosteering

摘要

Maximizing bitumen recovery from thermal horizontal wells requires optimal placement of the wellbore close to the bottom of the reservoir. Canadian Natural Resources Ltd. Is collaborating with Halliburton to utilize logging while drilling (LWD) techniques to achieve optimal well placement in relatively thin heterogeneous reservoirs of the Clearwater Formation in its commercial cyclic steam stimulation operations in east central Alberta, Canada. Halliburton’s StrataSteer3D ? service is used both prior to, and during, drilling in real time to plan, model, and steer the horizontal well. Resistivity, and gamma ray are monitored in real-time to detect the base of the reservoir during horizontal drilling and thereby geo-steer the well one meter above the reservoir base. Real-time data are used to recalculate well plans as new surveys and petrophysical data are acquired. Data collected are integrated using DecisionSpace ? for 3D geological modeling and well planning. Geological surfaces are revised while drilling and are applied to successive wells. Log responses are also characterized and correlated to the known area geology. This method of using the bit to steer by, and refine, the geology results in a reduction in overall drilling time by eliminating the need to intentionally ‘tag’ the bottom of the reservoir. Wellbore completion is also improved by ensuring maximum steam contact with the reservoir. The precision of vertical wellbore placement is increased thereby giving greater confidence in subsequent reservoir performance characterization.