Case History: Successful LWD Formation Evaluation and Drilling for Petro-Canada, at Wilson Creek, Alberta

摘要

Conventional horizontal drilling in thin pay zones relies primarily on the on-site interpretation of geological samples and gamma ray data in order to confirm that the bore is in the target formation. Three issues make this process difficult. First, sample lag and processing time can slow down the making of timely decisions related to the steering of the well. Second, it is difficult to infer porosity from gamma data without the availability of high quality, reference porosity data during drilling. Third, positioning a horizontal well within the sweet spot in a thin reservoir requires extensive working knowledge of area's geology; such knowledge is not always available. By utilizing the azimuthal litho density (ALD~(TM)) tool in combination with the compensated thermal neutron (CTN~(TM)) tool, and the resistivity and gamma ray logs for two wells, Petro-Canada was able to increase the percentage of a well drilled in the targeted porosity layer by geo-steering the well in real time. Precisely-controlled geo-steering in thin pays zones allows for optimum penetration of preferred porosity zones. A combination of formation-evaluation-while-drilling tools generated high quality wellbore images. These images revealed bore hole spiraling that is caused by drilling with conventional BHAs. This paper discusses the use of extended gauge bits and matched mud motor technology to minimize borehole spiraling to improve wellbore quality. The combination of geo-steering while drilling and Fulldrift~R drilling suite technology allowed the wellbore to be optimally positioned in the zone of interest and increased the percentage of net pay drilled.