Managed pressure drilling (MPD) is a technique used to drill wells when conventional rotary techniques are inadequate. MPD technology enables narrow-window and severe-loss wells to be drilled by controlling bottomhole pressure (BHP) and through early detection of any influx or losses. This paper discusses a campaign involving three wells drilled in the Brazil presalt area using MPD technology and analyzes lessons learned. Operational procedures are primary to the analysis; however, kick detection and system logic are also discussed, as this case represents the first use of the new MPD technology in a deepwater presalt scenario. The MPD system can be divided basically into two parts: (1) the flow deviation system, which enables a closed loop to be created to control flow deviations and (2) the pressure management system, which controls BHP by opening and closing an automated choke and measuring flow out. The pressure management system is enhanced by surface equipment, such as an automated choke and Coriolis meter, and the control software that receives all the information to control choke opening and closing analyzes data to detect and control any kicks or losses. This paper focuses on the surface equipment and software applied and discusses the results, challenges, and savings resulting from MPD technology use.

Drill-stem testing (DST) is a proven method for reservoir characterization, which is important when designing well completion, future development strategies, and stimulation needs. If the completion designer has the ability to acquire accurate knowledge of fluid behavior as the hydrocarbon is produced to surface, decisions concerningcompletion strategies and expectations during well life can be greatly facilitated. The capability to collect a single-phase sample also is critical to reservoir modeling, as is achieving correct analysis of collected reservoir fluidswith accurate data collection frombottomhole gauges. Samples must remain as single-phase fluid samples during recovery, and introducing high-pressure nitrogen behind the sample helps maintain sample pressure. By monitoring nitrogen-charge pressure in the sampler carrier, the exact time the samplers are fired is known. Thus, monitoring gauges will show any abnormality such as whether the annulus was pressurized or if the samplers were fired at an unwanted moment. By integrating the sampler carrier gauge with a wireless acoustic data-acquisition system, status and confirmation of success of the trigger device are provided. Also, casing-pressure limitations are reduced by actuating downhole tools using acoustic telemetry instead of annulus pressure. This paper discusses offshore field operations in Brazil to illustrate the importance of correlating gauge data from sample well fluids with a wireless acoustic telemetry system, and also, how the successful application of a wirelessly controlled DST work string composed of a data-acquisition system, an acoustically controlled tester valve, and samplers can significantly improve well-testing strategies.

Flexible riser systems are widely adopted by the industry as solutions to interconnect subsea equipment and pipelines to floating production units. Their unique ability to withstand motion and their ease of installation make flexible riser systems a favorable solution when compared to conventional rigid riser systems. Historically, the integrity of flexible risers has been an issue and it is therefore critical that risers are designed and qualified according to the current continually challenging operating conditions. Flexible riser integrity management and complex riser qualification processes have consequently become the main focus for major operators in guaranteeing the safety of offshore operations to reduce the risk of human, environmental and material losses. The industry has requested several qualification tests to verify the manufacture of the new flexible risers, e.g. a dynamic fatigue test, which is required to qualify the flexible pipe for deepwater installation. A means of monitoring the flexible riser response is also required in order to record the integrity of the riser and assist operators in identifying and implementing suitable remedial action, ranging from inspection plans through to riser replacement, as necessary. Based on these requirements, Pulse Structural Monitoring developed an armour wire failure monitoring system and, after extensive testing including offshore tests, validated the system through a full-scale dynamic test cycled to damage 1.0 (safety factor 10), performed by Wellstream. This test continued for more than one year and validated the monitoring system that was able to detect 100% of the wire breaks. This paper presents the results and conclusions from the blind test conducted to qualify the monitoring system. The results demonstrate that the monitoring system was able to detect the wire breaks caused during the full-scale dynamic test and would be a suitable solution to employ on flexible risers to detect failures in the field. Introduction Flexible risers are responsible for oil and gas transportation of approximately 80% of Brazilian offshore production and are mainly used in highly dynamic loaded environments, where outstanding fatigue performance is essential. Flexibles are commonly used in today's harsh ultra deepwater developments and play an outstanding role in deepwater offshore operations worldwide. Given that the depths are increasing where flexibles operate, environmental conditions are becoming ever more challenging, and the engineering challenges in designing and manufacturing risers are also increasing. There are more than 1,200 flexible risers currently in use offshore Brazil whilst over 1,000 flexible risers are operational in the North Sea. A complex engineering process takes place for the design and fabrication of flexible risers, based on presumptions about environmental loading conditions and the specific requirements of the application over its lifetime. As production expands into increasingly deeper water depths, more advanced riser designs and qualifications are required from offshore operators.

The new era of hydrocarbon production and exploration has required continual technical change to enable the challenges presented by the more hostile environments into which exploration has now moved to be resolved. The new Brazil well environments include not only high-pressure, high-temperature (HP/HT) wells, but also extreme high-pressure, high- temperature (extreme HP/HT) wells. To test these wells, the projects have depended on improvement in available technology, since formation evaluation jobs now are required for the more difficult conditions in the high-pressure, high- temperature (HP/HT) wells. The definition of HP/HT well environments are those with bottomhole pressures above 10.000 psi and bottomhole temperatures above 300° F. When environments have bottomhole pressures above 15.000 psi and temperatures above 350° F, the wells are considered as extreme HP/HT. Until recently, downhole tools available for standard projects could function efficiently to approximately 350° F and up to 10,000 psi of pressure. However, special tools are now available for 450° F and 15,000 psi of differential pressure conditions. These tools could possibly function in higher pressures and temperatures, but often, the drill-stem test (DST) string design is limited by the capabilities of other components in the string. Challenges also concern memory gauges, which can work in temperatures of 400° F and 30,000 psi of absolute pressure, but real-time gauges available can only reach 350° F. For HP/HT wells, therefore, mechanical pressure and temperature gauges had to be used. There were also other challenges for downhole tools since the well-fluid type could cause some inconveniences such as solids decantation and low-pressure transmissibility that would affect the valves. Special attention also is required for the elastomers used, since they must be compatible with well fluids and temperatures. Now, however, thanks to the development of new technology, a formation evaluation job can be performed in extreme HP/HT wells, since tools and elastomers have now been developed that perform in a 20,000-psi and 400°-F environment; for 350°-F jobs, real-time downhole gauges are available; for 700°F wells, mechanical pressure and temperature gauges can provide P&T data that can be exported as an ASCII file, thanks to the new chart-reading capabilities now available. In Brazil's ultra deep wells, the projects now include formation evaluation jobs in HP/HT wells. This paper will discuss how formation evaluation jobs can be performed satisfactorily in extreme HP/HT wells with up to 20,000-psi and 400°-F environments by changing operational procedures for the tools and elastomers presently available. This paper discusses lessons learned that have provided: information for testing in extreme environmentswhich gauges are appropriate for specific conditionshow to perform a DST by adapting special procedures for use in hostile environment. The improved technology and information concerning testing in extreme environments have enabled improved drill stem testing operations to be performed in the extreme HP/HT reservoirs in Brazil using these methods.

Hydrocarbon exploration and production has ventured into deeper, more corrosive environments, requiring continual technology changes to address the challenges presented by the new environments into which the oil field has moved. Testing technology has had to redefine the operating envelopes for its tools in order to meet the new requirements. Not only high-pressure and high-temperature tools have been needed, but more debris-tolerant tools have been needed as well. This paper discusses the application of downhole testing tools in formation evaluation jobs in extremely hostile environments; these include testing in such conditions as: Ultra-deep waterExtreme high-pressureExtreme high-temperatureDebris presence. Ultra-deep-water wells are those that have at least 10,000 feet of water depth, and HP/HT well environments include those with bottomhole pressures above 10,000 psi and bottomhole temperatures above 300°F. When environments have bottomhole pressures above 15,000 psi and temperatures above 350°F, the wells are considered as extreme HP/HT. Many testing operations have been severely challenged by these scenarios, as downhole tools available for standard projects only were capable of functioning efficiently to approximately 350°F and up to 10,000 psi of pressure. Now, special tools are available for conditions with temperatures of up to 450°F and 30,000 psi of hydrostatic pressure with maximum 15,000 psi of differential pressure. In addition, a new generation of more debris-tolerant tools is available. The improved tools have enabled high-quality well testing to be performed safely, and when the tools are used in wells where solids problems are not anticipated, and unexpected debris does occur, they can avoid the unexpected rig time previously required to clean the well, further enhancing economic efficiency. Debris-tolerant tools also have allowed fracturing and acid operations to be performed with a test string, and with the same string, the well can be opened to a well-testing operation without compromising the functioning of the downhole tools. Subsea equipment also has required adaptation to harsh environments. A major engineering/service company has now developed new subsea safety-tree equipment to be placed inside the BOP stack; with this new equipment, the fracturing operation and the drill-stem testing can be performed in the same trip, since the safety valve system has the capability to maintain integrity when functioning in heavy proppant, high pressure, and high pump-rate conditions. This capability saves time and adds economic value as well as increased safety features to the jobs. This paper will discuss the innovations to testing technology as well as how formation evaluation jobs now can be performed satisfactorily in extremely hostile wells using the improved technologies. Best practice information that has now been gained concerning testing in extreme environments will also be presented.