With many horizontal open hole completions beyond the reach of coiled tubing, the need arises for a reliable conveyance system to access the wells. Several types of tractors are available for cased-hole well completions. These tractors can be run in specific hard formation open hole horizontal wells, however all types failed in accessing openhole wells in softer formation. Open-hole completions in carbonate formations have been quite challenging for tractors. Initially designed for cased-hole applications the major technical challenge is gripping in a soft formation with sufficient radial force to provide a required tractoring force whilst not slipping. The major gripping/slipping issues have been faced in formations with an Unconfined Compressive Strength (UCS) of less than 5000 PSI. A new innovative design has been introduced that addresses the needs for logging these openhole horizontal wells in soft formations. Several phases took place in the development; such as design, laboratory testing, field testing, evaluation, upgrades and modifications. The latest design was first tested in hard formations prior to the unique challenge of logging horizontal open hole wells in relatively soft formations. Fields where the new design was tested were considered a real challenge for all logging conveyance methods. Successful operational results have been achieved for the first time worldwide. This paper describes the whole process history from challenge to success, giving clear steps towards successful logging of openhole soft formation horizontal wells. Discussed are the evaluation that led to the new tool design, tool design overview, laboratory and field tests, selection criteria of the candidate wells, review and screening of the well candidates and operational results. Introduction In December 2002, a successful testing of a cased-hole reciprocating tractor was performed in openhole hard formation horizontal wells in Saudi Arabia. The engineering design of this tractor was based on cams that grip the inner wall of the casing or openhole formation. The same design failed in a soft formation test due to the low Unconfined Compressive Strength (UCS) of the formation. The low strength allowed the cams to dig into the formation and lose the gripping force. After several tests, it was decided that any formation with UCS below 5000 psi would be considered as soft formation for this purpose, Figure 1 shows the UCS of the two different types of formations. The same tool design also faced problems in nonuniform shape of openhole boreholes. A complete redesign of the Tractor concept was necessary.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe need for a safe and cost effective conveyance method in horizontal well logging increased with the increase in the number of horizontal wells and their horizontal section length. Coiled tubing was initially used for conveyance, however it has a limited reach and the operations are complicated with some operational risks, demanding logistics and higher cost.The inchworm tractor was tested and evaluated in various horizontal well completions such as cased hole, slotted liner, gravel packed, ESP, open hole, and multilateral wells; with long horizontal sections. The tractor was also tested in open hole completions where the formation unconfined compressive strength (UCS) varies from 150 to 23,000 psi.Logging wells with soft formations was the most challenging task. The tractor design was modified to be able to initiate and maintain tractor movement in the soft formation. This paper will cover the test results of the inchworm type tractor such as effectiveness of conveyance, quality of logged data, maximum logged horizontal section and cost saving. It will also discuss the limitations of this technology. The screening process of suitable candidates as well as pre-job planning will be summarized.

Saudi Arabia is blessed with the world's largest onshore and offshore reservoirs. Currently Saudi Aramco is aggressively pursuing production increment ventures, one of the main components being the development of stringers which are present among all the major offshore oil fields. One of the technology contributions to Saudi Aramco's effort is proactive geo-steering using Directional and Deep Resistivity technology to maximize the net sand delivered from each well. The drilling of development wells in sand stringers involves very thin and sinuous targets. These targets are the channel sand stringers and contain a substantial amount of hydrocarbons. Optimal well placement is a requirement for these very thin reservoirs in order to drain them in a cost effective manner. Conventional well placement has met with limited success in stringers and thus resulted in low production figures. PeriScope has persistently proven that a proactive well placement technology can be translated into maximum reservoir contact, minimum well-bore tortuosity and a facilitator for optimal production. Due to the uncertainty that is inherently present in the distribution of the channel sands, the prediction of the azimuth of channel meander can now be confidently solidified with new deep and directional electromagnetic measurements. By detecting the upper and lower conductive shale boundaries the wells can be steered in this very challenging environment of channel sands. In the past two years Directional and Deep resistivity technology has delivered over 110,000ft of challenging reservoir to Saudi Aramco. This has also been an enabler for multi-segment collaborations and is now seen as a premium well placement service within Saudi Arabia. This paper will highlight how these innovative technologies have impacted the stringer sand reservoir development in multiple offshore oil fields of Saudi Arabia. Introduction With the growing demand for energy, pressure is mounting to improve recovery factors and extract as much hydrocarbon as possible from complex and challenging reservoirs. This is coupled with the fact that many of the easy oil and large thick reservoirs of Saudi Arabia have been already drilled and now smaller, thinner and more complex reservoirs are being considered for development. One of these developments is of Khafji stringers on structure flanks of several offshore fields.

This reference is for an abstract only. A full paper was not submitted for this conference. Abstract The emergence of extended reach horizontal drilling technology offers unique opportunities for improved hydrocarbon recovery. There has been a steady progression in the vertical depth and horizontal departure length of ERD wells. In Saudi Arabia, development drilling programs increasingly require directionally drilled well trajectories to reach the bottom hole targets. Recent developments in horizontal well-placement and drilling technology enabled us to successfully drill and geosteer one of the longest openhole power water injector wells in Saudi Arabia. Complexities in the placement of this extended reach well located on the flank of a field included : a target that was characterized by high formation dip andno offset well control, leading to the reservoir having unknown structural dip and azimuth. It is also common for ERD-well paths to cross faults, sometimes with unfavorable displacements and orientations. Advance geosteering methods using 3D visualization and real-time borehole images were utilized to detect a sub-seismic fault, and successfully side track and steer the well to remain in good porosity for the entire horizontal section. Real-time images enabled an accurate depiction of the formation dip. Combined with 3D structural modeling updates, this approach proved invaluable in successfully placing this extended reach borehole.

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