Advanced multilateral well drilling & completion requires the application of innovative technologies while drilling to place the well in sweet spots by managing all the geological uncertainties. The smart level-4 multilateral well with dual stacked lateral was drilled by integrating advanced Real-Time geo-steering formation characterization along with geochemical, advanced gas analysis and seismic data interpretation.The Burgan reservoir consists of vertically stacked channelsands associated with geological heterogeneities along with series of fault networks connected to the aquifer at the bottom. The reservoir contains ultra-high water mobility with down hole oil viscosity of about 40cp enhances water breakthrough and requires customized ICD and ICV completions to enhance dry oil production and maximize oil recovery. Real-time geo-steering performed on Multi-lateral well by utilizing advanced technologies including High resolution Geochemical Analysis has been utilized in Real-Time to identify "geochemical proxies" and allow geochemical steering, distance to boundary tool using 4 resistivity curves with deep spacing Geosignal, At-bit measurements and density image to correct well positioning and locating faulted areas. The pre job planning had two components such as: (i) building a geosteering model based on offset well logs, geological and geophysical information and (ii) preparation of geochemical model based on XRF analysis of core chips from offset wells. The later model was calibrated through logs and utilized further to predict key rock attributes such as: (a) detailed lithological variations generally beyond the resolution of LWD logs, (b) detailed mineralogy to determine the diagenetic overprint and (c) depositional environment of different Burgan sand facies. Continuous interpretation and integration of XRF and petrophysical analysis supported by LWD data was a key factor for real-time geosteering operation. Such integrated approach also resulted in successful placing the wells with maximum reservoir contact and also was very instrumental for (i) isolation of potential trouble zones, (ii) segmentation of horizontal sections and (iii) optimization of nozzle sizes of the ICDs and hence planning of smart completion designs.

The Middle Cretaceous Upper Burgan and Wara sandstone reservoirs in the Minagish field are exhibiting variable clastic depositional settings ranging from fluvial, fluvio-tidal to tidal wave sands. The sand bodies are highly heterogeneous in terms of the stratigraphic architecture implying extensive lateral facies variations, stacked sand bodies and varying petrophysical properties. Modeling the target sand channels and optimizing subsurface well placement and geo-steering requires high resolution geological and seismic data integration in order to minimize uncertainities related to correlations of multiple auto-cyclic ravinement surfaces, channels geometry and sub-seismic fault network. Within Upper Burgan and Wara sand bodies there are different lobes that have varying degree of minerals like glauconite, pyrite and hematite with other cementing materials such as calcite and dolomite. The presence of glauconite has a strong impact on petrophysical evaluation, whereas the presence of shale poses several challenges during geosteering. Geostatistical modeling for sand distribution were integrated using seismic data, core and sedimentological models, electrofacies and petrophysical intrepretations. High resolution seismic data including pre-stack depth mighration and pre-stack simultaneous inversion have been utilized with well log curve shales and elastic impedance to trace accurately the good quality sand. High resolution sequence stratigraphic model were attempted on this complex Upper Burgan and Wara formations. The formation evaluation and geosteering challenges were addressed to ensure the successful drilling and completion of horizontal producers. The wells drilled in this complex settings are geostreed with high definition inversion based distance to boundary technology having a higher precision and accuracy of resistivity contrasts. Formation capture cross section (sigma) saturation was of great value in "mixed lithologies" of Upper Burgan and Wara as resistivity frequently polarized from the proximity to bed boundaries and in these portions traditional resistivity logs proved ineffective for saturation evaluations. In addition the real time permeability estimation using spectroscopy analysis was very beneficial to ICD design.