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Extended reach and highly deviated wellbores enable operators to intersect multiple reservoir targets with a single wellbore, a capability that would not have been possible had the well been drilled vertically. The driver for drilling these kinds of wells is to reduce the total cost of developing a field. With advances in drilling motors and rotary steerable systems, drilling these types of wells has become common, but there are still challenges in acquiring sufficient formation evaluation data. Often these wells are drilled in already producing fields where depleted zones will be encountered. This, coupled with the high deviation makes wireline conveyed evaluation risky and expensive, in particular since these well types typically require pipe conveyed wireline operations. Logging while drilling (LWD) tools have been able to provide sufficient petrophysical data for the better part of two decades. It is only in recent years that it has become possible to acquire formation pressure data while drilling and thereby provide critical answers to operator asset teams with regards to fluid type, well-to-well connectivity, and depletion trends. In a drilling campaign in Southeast Asia two highly deviated wells and two extended reach wells were drilled and evaluated successfully using LWD technology both for petrophysics and also formation testing, with an ultimate economic advantage to the operator compared with wireline logging. A formation pressure while drilling (FPWD) service was used to measure formation pressure and record fluid gradients. This paper details the operator's objectives, perceived challenges, operations planning, and the ultimate execution and real time support that made this application of FPWD technology a success.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWithin the Saudi Aramco organization, complex reservoir formation evaluation is regarded as a key discipline -fulfilling a critical role in maximizing production and facilitating accurate estimation of reserves. The timely acquisition of high quality and detailed petrophysical properties of the various reservoirs in Saudi Arabia is central to this role. Towards this end, Saudi Aramco Reservoir Description Division (RDD) introduced a new-generation multi-functional LWD (Logging-While-Drilling) technology into Saudi Arabia, has been directed to evaluation of on-shore complex carbonate reservoirs.The traditional LWD measurements of propagation resistivity, gamma ray, density and neutron porosity along with advanced gamma ray capture spectroscopy measurements into a single compact collar. The electronic pulsed neutron source required for the spectroscopy measurements also provides a much improved neutron porosity measurement 1 . This technology has been used in a number of Saudi Aramco horizontal wells in carbonate and clastic reservoirs. The data from these wells has been comprehensively evaluated. The results of the evaluation of the data acquired by the new tool and conclusions about the tool's introduction into Saudi Arabia are summarized in this paper.

TX 75083-3836, U.S.A., fax +1-972-952-9435

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