fax 01-972-952-9435. AbstractDuring the past 7 years, rotary steerable drilling technology has emerged from prototype status to a standard application world wide. This paper focuses on the latest generation integrated Rotary Closed-Loop System which now enables the industry to benefit from this technology in hole sizes from 5 7/8"-18 ¼". The paper discusses the integrated BHA concept and the sequential implementation of additional BHA components. Modular positive displacement motors placed immediately above the steering device simultaneously gives another step change in drilling performance while reducing casing wear and extends the drilling envelope. The paper provides an insight into applications where the integration into the rotary closed-loop BHA, of real-time Logging While Drilling (LWD) formation pressure measurements and real time acoustic property services has complimented, or indeed eliminated the need for, wireline logging runs.Using such an integrated Rotary Closed-Loop System in the Norwegian Troll Field created incremental production revenue of 6 Billion USD.

This paper describes the design criteria and operational experience with a new, second-generation Rotary Closed Loop System (RCLS). Rotary Closed Loop Systems are clearly revolutionizing the way in which oil & gas wells are drilled. During the past 5 years the technology has emerged from prototype status to a standard application in locations with good infrastructures such as the North Sea and the Gulf of Mexico. In remote areas with more challenging logistics such as West Africa, Asia Pacific, and South America, the use of rotary steerable technology has been very limited. Based on the accumulated experience with a leading system, a new generation of Rotary Closed Loop System has been introduced specifically for remote operating areas. These areas have a relatively poor infrastructure, difficult logistics and some experience extreme environments. The paper describes the technological challenges that had to be overcome for the standard application of Rotary Closed Loop Systems in remote areas and illustrates the advantages to the oil & gas industry with some exemplary case histories. Introduction Rotary Closed Loop System (RCLS) drilling technology was first introduced to the North Sea in early 1997. The technology was ground breaking at that time without any significant parallels. It has been as revolutionary to the drilling industry as the introduction of Measurement While Drilling (MWD) or Steerable Motor technology was in the late 1970's and mid 1980's. The complexity of these new systems has been a significant challenge when it came to their wide spread use. In areas with short supply chains and good infrastructure like the North Sea, the new technology has widely replaced conventional directional drilling technology. It has become the standard drilling system for many fields in the 12. 1/4 inch to 8. 1/2 inch hole sections. To continue the expansion of the use of this technology, new system requirements were defined. These new system requirements are aimed at helping the industry explore and develop oil & gas resources more economically throughout the world, including the most remote areas. Design Criteria for the New Generation Rotary Closed Loop System The first generation RCLS has successfully replaced conventional directional drilling methods (such as steerable motor and MWD/LWD systems) in many fields. However, this has primarily been limited to high cost offshore operating areas with high activity and good infrastructure. This is a result of the fact that demand has continued to rapidly grow with new systems being added to the operating areas having an established infrastructure. As operators gained confidence in the technology, the demand spread to all areas of the world where high operating costs drive the need for developing oil & gas reserves more economically. A continuation of the high growth rate for RCLS applications is therefore still expected. Experience in the maintenance of the 1st generation product, in its field application, and in the build up of the supporting infrastructure to maintain and operate the system, led to a requirement for a new RCLS generation. Step change in reliability The first generation system has reached a reliability level comparable to the conventional directional drilling technology with steerable motors in combination with Measurement While Drilling / Logging While Drilling technology. The data shows that the reliability rapidly improved in the first two years of commercial application, Fig. 2. For the years 2000 and 2001, the reliability of the system has stabilized at a level of 75 to 80 % for the probability of successful runs. This trend indicates that no further significant increases are to be expected without major changes to the existing system. This has led to the first major design criteria for a new generation system - to achieve a step change in reliability. Step change in reliability The first generation system has reached a reliability level comparable to the conventional directional drilling technology with steerable motors in combination with Measurement While Drilling / Logging While Drilling technology. The data shows that the reliability rapidly improved in the first two years of commercial application, Fig. 2. For the years 2000 and 2001, the reliability of the system has stabilized at a level of 75 to 80 % for the probability of successful runs. This trend indicates that no further significant increases are to be expected without major changes to the existing system. This has led to the first major design criteria for a new generation system - to achieve a step change in reliability.

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Wireline formation pressure testing has been routinely used as a valuable reservoir characterization tool and its results are generally well-regarded. On the other hand, LWD formation pressure testing, initially introduced primarily as a drilling safety and equivalent circulating density (ECD) optimization tool, has yet to fully prove its effectiveness in reservoir evaluation, due to perceived data acquisition challenges. Today, re-entry drilling is used in many aging oil and gas fields to target the remaining hydrocarbon. Formation pressure, fluid gradients and the determination of whether or not compartments are in communication are important information when analyzing such reservoirs in real time for optimum wellbore placement. The cost efficiencies of acquiring formation pressure data while drilling are becoming more influential in the operator's technology selection process, but should not come at the cost of reduced data accuracy or data usability. This paper discusses new techniques and technologies that facilitate gaining a better understanding of the subsurface while drilling. These include a smart test function, which reduces formation shock while pressure testing in microDarcy formations and avoids sanding in highly unconsolidated formations. Performing optimized test sequences improves the accuracy of the pressure and mobility data and leads to higher operating efficiency. Further to this, LWD pressure testing on wired pipe yields a data density previously only found on wireline. The introduction of extended test times of up to 40 minutes broadens the scope of LWD pressure testing into traditional formation pressure testing applications, such as compartmentalization evaluation or fluid gradient analysis. Longer test times and testing on wired pipe precede future fluid sampling while drilling. Benefits for drilling and subsurface teams are equally important and one of the reasons why LWD formation testing has become a cross-functional discipline. Case histories from the Middle East will be used to highlight the recent technology advances and applications. Pressure Testing in Highly Unconsolidated Formations One of the extreme challenges for formation testers is pressure testing in highly unconsolidated sand formations due to different reasons, varying from formation strength over pad size and formation break-in during testing. Furthermore, the testing procedure has a big influence on the success of a pressure test. In the following sections, we discuss these effects in more detail.

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