APPLICATION AND INTERPRETATION OF MULTIPLE ADVANCED LWD MEASUREMENTS IN HORIZONTAL WELLS

摘要

Over the last 20 years, the oil industry has seen a dramatic increase in the complexity and the reach of production wells. These advances have been made possible by the introduction of sophisticated rotary steerable drilling and formation evaluation systems, enabling Hydro and other operators to place wells into targets in a more accurate and cost-efficient manner than ever before. This environment has placed an increased reliance on Logging-While-Drilling (LWD) measurements. In this paper, we will review a number of high-angle and horizontal wells drilled and logged on one of Hydro's mature North Sea fields and how the application of a number of advanced LWD technologies have enhanced answers through acquiring comprehensive formation evaluation data in a single run. The LWD technologies that will be presented range from standard measurements such as Gamma Ray (GR), multiple propagation resistivity, neutron porosity and density to real-time GR and density imaging, formation pressure and mobility and acoustic LWD compressional and shear measurements in both fast and slow formations. During late stages of field development where bypassed oil is to be drained, the data acquisition program will change substantially to acquire relevant information to ensure both optimal wellbore placement and maximum hydrocarbon drainage. Maximum available technology on LWD is applied to such complex horizontal and extended reach wells. The economic advantage with respect to time saving operations in the high-cost environment of the North Sea is obvious. The wells that are drilled in these offshore brownfield environments would not be possible without the high level of accuracy available from LWD tools today. The real-time aspect of LWD data acquisition is key to delivering answers while drilling that reduce reservoir and drilling uncertainty. Also, handling of the data in real time to ensure service quality and pro-activity, along with the post-processing of LWD data, are discussed and illustrated with examples to demonstrate the value of these technologies in achieving the goal of optimized reservoir access and productivity. The benefits from accessing the data while drilling will be discussed, including how real-time formation pressure measurements identify type of reservoir fluid early in the drilling process, as well as lithostratigraphic and petrophysical interpretation in horizontal wells to determine key petrophysical parameters, structural interpretation from LWD imaging and acoustic LWD including soft rock shear input to improve seismic resolution and well tie.