Integrating Horizontal Wells in 3D Geological Model Using Sequence Stratigraphic Framework in Braided Channel Complex of the Changbei Gas Field, Ordos Basin, China

摘要

Multi‐lateral horizontal wells are applied in Changbei Field to maximize economic development of tight gas sandstone reservoir. Reservoir models utilized for well planning were largely controlled by vertical wells. However, after drilling many horizontal wells, the reservoir model is required updating with horizontal wells to improve well placement and planning of the remaining horizontal wells. One of the prime challenges was effective and correct incorporation of horizontal well data into the reservoir model, this was particularly challenging in Changbei’s braided channel complex with high reservoir heterogeneity. Horizontal well objectives in Changbei Field are to drill 2km dual lateral wells into clean Quartz Arenite Sandstones that were deposited in high to moderate energy facies and avoid low energy and abandonment facies which are typified by dirty sandstone (lithic quartze arenites), carbonaceous claystone and shale. This objective has biased well data to the better reservoir quality in horizontal wells compared to vertical wells and subsequently results in significant deviation of facies distribution and reservoir properties. By integrating all data available including core, thin sections, wireline log, mudlog, outcrops and analogues data, this paper takes braided channel of Changbei tight gas field as an example on methodology of incorporating horizontal well data based on high‐resolution stratigraphic correlation. The result has a significant impact on Changbei Field Development Planning. The clarity in main sand reservoir distributions (QA Sand) has improved horizontal wells placement and planning to be more efficient and cost effective. This improvement has been proved by better history matched with production data and better predictability while drilling horizontal wells.