fax 01-972-952-9435. AbstractNew tools for Formation Testing While Drilling (FTWD) were introduced to the market less than two years ago. They are used in an increasing number of wells in a wide range of operating environments. The tools are capable of performing accurate tests in the dynamic drilling environment of rotary and rotary steerable drilling. They measure formation pressure and some provide formation mobility estimations in real-time. The application expands formation testing into extended reach drilling where pipe conveyed wireline testing is of high risk. It also allows formation pressure testing in boreholes where drilling risk or hole stability exclude conventional data acquisition. During FTWD operations circulation is maintained at all times to insure wellbore integrity. This presents a challenging dynamic environment for accurate formation pressure measurements.In this paper, the application of an FTWD tool in conjunction with a mud motor is described within an even more challenging environment, due to motor rotation and associated drillstring vibrations, as no circulation bypass valve was used. The Baker Hughes INTEQ TesTrak tool was capable of performing accurate formation pressure and mobility measurements with an overall success rate of over 80% in an extreme pressure and vibration environment. Pressure and mobility test results will be shown and compared to conventional wireline logging results from nearby wells. Mobility data, which are calculated downhole and transmitted to surface in real-time, are compared to previous well test data from neighboring wells. The FTWD mobility data showed a good match with reservoir simulation and core data, and even better agreement than the data derived from conventional wireline measurements.In this application the FTWD tool was run in combination with a triple combo LWD suite. This allowed real-time reservoir evaluation as well as optimizing pressure point selection during on-site formation evaluation. No additional wireline logs needed to be run afterwards and the hole could be cased immediately.

Drilling Exploratory and Appraisal wells can be challenging especially when faced with narrow mud weight / formation breakdown gradient windows and the potential for rapid pressure ramps. Operators engaged in the search for, and production of, hydrocarbon reserves in Tertiary basins are frequently confronted with complications associated with over pressured (abnormally high fluid pressure) formations. This is particularly the case in some of the Offshore Assets of Addax Petroleum. The problems associated with these formations are of direct concern to the combined activities of all phases of operations, which include geophysical, drilling, geological and petroleum engineering, thus the knowledge of the pressure distribution of a given area of operations would greatly reduce the magnitude of many of these complexities and in some cases, would completely eliminate them. This paper presents how the use of the Baker Hughes INTEQ "TesTrak™" tool has been used to measure formation pressures while drilling (before switching off pumps to make connections). On one exploration well, it was observed the well flowed when the pumps were switched off to make a connection, thus indicating the Equivalent Circulating Density (ECD) was providing the overbalance over the formation pressure. It is also important to note that there has been a transition in optimizing the efficiency and functionality of this tool where the the Bottom Hole Assembly (BHAs) have been re-configured with the TesTrak™ being run "upside down" so that the formation pressure measuring probe would be closer to the bit and thus enable the earliest possible formation pressure information, minimizing the likelihood of a pumps off event. The process of automatic cycling of the pumps, which was required to toggle the tool back to drilling mode was minimized (only with full knowledge and agreement of all involved in drilling operations), after it was observed how dangerous it can be loosing the the over-balanced supplied by ECD. To maximize the advantage of having the logging tool read formation pressures real time, the TesTrak™ has been used to take formation pressures to verify prognosed pressure transition zones such that the mud weight can be adjusted to suit the actual pore pressure measured.The TesTrak™ tool is presently also being used by Addax Petroleum for data gathering while drilling development wells eliminating the need to run wire-line or pipe conveyed logging in highly deviated and horizontal wells. This has saved rig time and drilling operations costs in addition to enhancing drilling efficiency. It has also improved well-site safety, helped optimize decision making and decreased the risk of differential sticking.

Directional drilling control in top-hole sections through very weak shallow sediments is challenging. The formation tends to wash out, reducing steering control. The lack of reliable steering results in well kick-off-points planned deeper than optimal, especially for extended-reach wells or under multi-well platforms where early well separation is advantageous. Additionally, when drilling in close proximity to existing wells, well collision risk increases. As a result of these challenges, a major operator and international service company have developed, and proven, a hybrid drilling technique enabling reliable steering control in sediments which previously proved difficult to directionally drill through. The technique employs an automated rotary steerable system (RSS) and gyro-while-drilling tool operating in a directional jetting mode without rotation. The wells are drilled from an offshore platform through dual conductors. In addition to the well collision risks normally associated with multi-slot platforms, dual conductors mean that the second well drilled from each conductor is initially in very close proximity to the first well. Until this technique was developed, the top-hole sections were drilled with steerable motors because RSS were unable to steer consistently in the very weak shallow sediments. When the collision risk was passed, and the formations became firm enough for the RSS to operate, the steerable motor bottom hole assembly (BHA) was replaced with the RSS. The hybrid RSS jetting technique provides several advantages; a single BHA run can drill to section TD, shallower kick-offs are possible and predictable steering control reduces the risk of collision. The lower energy of the non-rotating jetting system is also believed to reduce damage to an offset well in the event of collision. The paper explains how the hybrid system was developed, and describes how it is applied and optimised in practice with real examples. Opportunities for further research are presented which may enable offset wells to remain on production, saving significant production loss and avoiding risk associated with well shut-in and start-up.