Abstract

The planned production attainment, and correspondingly economical feasibility of hydrocarbons production in BP16 suite in Vostochno-Tarkosalinskoe (VTSM) field directly depends on successful placement of horizontal section. The reservoir is highly heterogeneous and Well Placement is utilized not only to maximize the reservoir exposure, but also for supplementary exploration and understanding of the complex geological settings. The information obtained in the process of Well Placement is used with the purpose of detailed geological modeling, which defines further field development plan.

BP16 suite is represented by turbidites, which dictates application of modern logging while drilling (LWD) technologies and Well Placement techniques. However, all previously utilized technologies have reached their limit in their capability of formation description. More specifically, significant lateral variations make utilization of standard triple combo measurements (Gamma Ray, resistivity, density and neutron) insufficient. Multiple unconformably deposited layers and localized bodies create a considerable challenge for interpretation of azimuthal data (images) and pose some limitations on the inversion of directional electromagnetic (EM) measurements, obtained while drilling with the bed boundary mapping tool.

The new multiple boundary delineation technique was used while drilling to improve understanding of the layers extent, apparent dip and unconformable bedding. This technique is based on the stochastic inversion of extended set of deep EM measurements. The inversion resolves for formation electrical anisotropy, formation dip and allows for mapping of multiple boundaries in real time.

This paper is describing the experience of drilling horizontal wells in the VTSM field, where the multilayer inversion technology was used for Well Placement for the first time in Russia. The new technology was utilized not only for Well Placement, but also to obtain detailed information on geological settings around the wellbore. Geological modeling was later rectified based on this information and used for field development plan justification and formation pressure maintenance (FPM).

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