As exploration has moved into deeper, more hostile environments, drill-stem testing (DST) has had to address new challenges related to testing in these ever-changing, more demanding environments. These new scenarios have required continuous technology innovations to enable DSTs to meet the additional needs inherent to the deeper offshore environments. Testing technology has had to find solutions for these conditions, while maintaining cost optimization and operational safety, both of which present continuous concerns. One strategy has been to reduce the use of electrical cables in the well and minimize the application of pressure to the annulus. This paper presents the industry's first fully acoustic telemetry controlled and monitored real-time drill-stem testing (DST) operation performed in a deepwater environment. The fully acoustic controlled operations included:• Opening tester valve for flow • Closing tester valve for build up • Opening circulation ports • Actuating downhole samplers • Acquiring real-time pressure and temperature data.This job was performed in the pre-salt region of southeast Brazil from a semi-submersible rig at 7,053-ft water depth in a well that was17,600 feet deep. In this DST, a completely wireless acoustic system was used to control the downhole tools, and as such, had to actuate the tester valve, the circulation valve, and the bottomhole fluid sampler, while acquiring real-time bottomhole pressure and temperature data. This was the first time that this type of operation had been attempted in deep-water conditions. Acoustic telemetry systems usually can help optimize operational cost because of their capability to access quickly real-time data pertinent to the reservoir evaluation; because of this capability, immediate well-timed decisions or changes to operations can be made. The fully wireless system (acoustic wireless transmission across the subsea safety tree and its components) provided the operator with acoustic feed-through response, which enabled troubleshooting from the surface and capability to change the "next steps" for the DST quickly.This paper also discusses how the use of these tools elevated testing operations to a higher performance level and improved quality standards.

The Drillstem Test (DST) is an important process used to gain knowledge and understanding about a reservoir, from identifying the characteristics of its oil and gas, to production planning, extending as well to the commercial viability of the entire reservoir. Since 1920, the need to better understand reservoir conditions has driven numerous technology developments throughout different generations. These technologies have helped define reservoirs in harsh conditions. Through the continued search for innovative DST solutions for the challenging deepwater scenario, a new generation of DST tools was successfully achieved. This technological package of downhole tools were influenced mainly by the communication method applied. The acoustic telemetry system is the backbone of the downhole tool network system, providing an efficient and effective bi-directional communication link between the data acquisition computer in the rig control cabin and the tools located down hole. This paper presents how wireless acoustic control of drill-stem test tools can improve cost efficiency and safety in DST operations by: Reducing risks associated with the use of annulus pressure to actuate downhole toolsReducing casing-pressure limitations by using lower applied annulus pressureReducing and, in some cases, eliminating the use of wireline operations in the wellAcoustic signal not affected by mud weightAllowing optimization of the operations by providing real time data monitoringAllowing accurate status feedback and diagnostic from the down hole tools, reducing uncertaintiesReducing the duration of each period of the operation can potentially reduce rig timeAdding redundancy capabilities (tools can operate with means other than acoustic as backup)Comparing with wireline based systems in allowing real-time data acquisition during all the periods of the operationReducing number of personnel necessary in the rig by allowing remote access and analysis of the data The system was first-time deployed in a semi-submersible rig in a pre-salt region of southeast Brazil. The fully controlled operations included: Opening tester valve for flowClosing tester valve for buildupOpening circulation portsActuating downhole samplersAcquiring real-time pressure and temperature dataTransmitting real-time data to customer officeAnalyzing data in real-time This paper will discuss how this new full telemetry acoustic system elevated testing operations to a higher performance level, improving cost efficiency and safety in DSTs for deepwater application.

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The paper discusses how a new burner can solve environmental challenges in well test applications by reducing the quantity of fallout, providing better control of the burning operation, and allowing operators to adjust to changes in the well/weather conditions. In order to conduct successful well tests, substantial amounts of oil must be brought to the surface, and in most instances, the safest and least expensive method of disposal is to burn the produced oil. A quality smoke-free burn and drip-free operation is enabled through an innovative advanced nozzle design installed in this new oil burner. The nozzle can precisely control the flow of oil and air through the burner allowing, for the first time, closure with no unburned fuel escaping. The nozzles are operated remotely and powered by an integrated pneumatic system using the combustion air supply. The system permits control over each individual nozzle, enabling operators to adapt to varying flow conditions to maintain efficient and flawless performance. A wide range of tests were conducted, including combustion zone gas sampling and fallout testing. Over a three week testing period, the new burner flawlessly executed full-scale burns and provided on-the-fly nozzle control, burner head rotation, and instant drip-free shutdowns. The new burner demonstrated its capability to shut down all ten nozzles from their full capacity in three tenths of a second with no visible unburned hydrocarbons or drips. The new burner achieved a 99.99952% fallout efficiency; this is 14.58 times more efficient than any other current oil burner product offering. In addition to the exceptional fallout efficiency, it also delivers 99.4% combustion efficiency and 99.5% destruction efficiency allowing the calculation of CO2 emission rates, which during testing was found to be 41Lbs/MMBtu. The first operation was conducted offshore in Brazil where this new burner demonstrated the capability to control, monitor, and react to changing well conditions for approximately three days without issue. It flowed in excess of 6,700 bbls, preventing a minimum of 69.48 liters of fallout from entering the sea. A total of 32 jobs were performed with the new burner system from December 2014 to January of 2018 with a 100% success rate without contamination/fallouts. The totally eliminated fallout volume, compared with the second most efficient burner system available in the market, is 2653.22 liters after burning a total of 257,490 bbl of hydrocarbons. In 60% of the field jobs, the burner was rotated to accommodate wind direction or to improve burning efficiency. If a different burner system had been used, the burner efficiency would have lessened or, in a worst case scenario, the operation could have been delayed and the well shut in until wind direction changed sufficiently to allow the burning operation.