With the advent of new age real time drilling technologies, the amount of data generated downhole has increased tremendously. Complemented by superior telemetry, the ability to transfer data uphole has increased by many folds too. With the introduction of new generation geosteering and reservoir mapping applications, it is possible now to integrate conventional logs with deep directional electromagnetic resistivity and advance formation evaluation measurements for accurate bed mapping, real time assessment of reservoir quality, structural dip calculation and forward planning trajectory – all in an integrated and single platform. The result is informed decisions and highly optimized results. The paper will discuss on a case study using this innovative integrated platform where geologists, drillers and geosteering engineers worked in sync to come up with the best possible real time decisions for optimum well design and placement, in a clastic reservoir, reducing overall well construction risks and negotiating the challenges of undesired geological events like trajectory drilling through a fault.
The interpretation of deep directional electromagnetic propagation measurements via highly sophisticated inversion algorithms gives information on the spatial position of the wellbore w.r.t reservoir boundaries. The remote detection of boundaries up to 20 ft around wellbore, gives us the edge for trajectory forward planning by predicting upcoming structural trend, in other words called Proactive GeoSteering. Conventional logs combined with high end measurements like spectroscopy, sigma, source less density and neutron provide accurate real time formation evaluation while drilling which enhance decision making of geo-steering process. Availability of these high-end technologies would allow operators to place horizontal well as close as possible to top reservoir, optimizing long term well performance by minimizing attic oil and delay water production.
The case study represents how latest state of the art real time drilling technologies coupled with advance geosteering techniques successfully helped overcoming various geological uncertainties encountered while drilling a horizontal well. Unexpected minor sub-seismic fault was successfully mitigated which avoid undesired non-productive time and lost productivity of the well. The results were very encouraging in terms of well production, and optimum placement of the horizontal well which will enhance long term recovery.
This paper provides new insight on successful application of multi boundary mapping technique in optimizing well placement in top part of the reservoir and offers approach for drilling horizontal wells in similar case of complex clastic reservoir. The technique also discusses mapping of sub-seismic faults that cannot be identified by normal seismic data, and how to mitigate subsequent risk of the fault.