New Subsea Safety Tree for Extreme Environments Successfully Meets Challenges in Brazil for Drill-Stem Testing/Fracturing Jobs

Marcancola, Fernando; Nolasco, Hugo; Barcelos, Rita; Rubio, Luciano Espinosa

doi:10.4043/24440-ms

Cited by 2 publications

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“…This additional time could result in increased costs per trip of more than USD 1 million. The newly developed SSST also reduces the steps traditionally performed during a fracture job pumping procedure because it can eliminate two trips (48 hours), which equates to a savings of more than USD 2 million per job (Rubio et al 2013).…”

Section: Subsea Safety System Tree For Fracture Jobsmentioning

confidence: 99%

Case Study: Hydraulic Fracture Treatment with Proppant During Drillstem Tests with Same Temporary Completion String

Engel

Azevedo

Marcancola

2015

SPE Latin American and Caribbean Petroleum Engineering Conference

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Historically, a fracture treatment with proppant is performed with a dedicated workstring connected to downhole completion equipment (such as a permanent packer, a tubing seal receptacle (TSR), or a locator assembly). This paper discusses offshore field operations in Brazil to illustrate how surface and downhole equipment, including a temporary completion string, were capable of meeting these challenges for hydraulic fracturing using ceramic proppants, followed by an acid job before a drillstem test (DST), which saved at least 6 days of rig time.When performing a DST with a temporary completion string, there are risks associated with using this type of fracturing treatment these mechanical tools can lock up if they are operated with proppant still packed in the operating sections (such as the tester valve and circulation valve). It is recommended that during the job the tool operation should be minimized to the absolute minimum because proppant can be packed in other areas of the tools. Halliburton performed extensive testing before the operation to determine the erosional limits of the DST tools; as a result of this testing, the maximum flow rate of the fracturing process was limited to 23 bbl/min. In this treatment, debris-tolerant valves, rather than standard valves were used. The debris-tolerant valves were specifically designed and tested to manage more debris.The well-test surface equipment was made of a solid-tolerant design, including a choke manifold (high abrasion tolerance), a four-phase separator, which was used to separate the solids, and surge tanks that are suitable for managing well flow that contains solids. Additional atmospheric tanks were provided in the test plant as part of a contingency plan to store fluids in the event of a high concentration of solids or/and untreatable fluid, which cannot be discarded or burned; sensors for solids were installed downstream from the choke manifold.During the hydraulic fracturing operation, 2,760 bbl of fracturing fluid containing the 20/40 mesh size proppant was pumped at a rate of 23 bbl/min with a maximum concentration of 6 lbm/gal. During the fracturing job, a screenout occurred, and the contingency plan was followed, removing most of the proppant inside the string. The well-testing plant received 130 bbl of the fracturing fluid at the surface during the cleanup of the well. The DST tools were fully functionable after the fracture treatment, and the test was successfully performed.The main objectives of well testing included the characterization of the reservoir (primarily, all variables to calculate the productivity index and the reservoir fluid (specific gravity (SG) of oil and gas/oil ratio (GOR). A stimulation technique is commonly used to increase the PI, and in some cases, with exploratory wells, the stimulation and well testing are combined to gather information to determine the effectiveness of the technique and whether or not this method is sufficient to make the block lucrative. One of these stimulation techniques is hydraulic fracturing, whi...

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Section: Subsea Safety System Tree For Fracture Jobsmentioning

confidence: 99%

Case Study: Hydraulic Fracture Treatment with Proppant During Drillstem Tests with Same Temporary Completion String

Engel

Azevedo

Marcancola

2015

SPE Latin American and Caribbean Petroleum Engineering Conference

Self Cite

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Downhole Testing Tools in Extreme Environments

Marcancola

Pontes

Adriano

2014

SPE Latin America and Caribbean Petroleum Engineering Conference

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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.

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New Subsea Safety Tree for Extreme Environments Successfully Meets Challenges in Brazil for Drill-Stem Testing/Fracturing Jobs

Cited by 2 publications

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Case Study: Hydraulic Fracture Treatment with Proppant During Drillstem Tests with Same Temporary Completion String

Case Study: Hydraulic Fracture Treatment with Proppant During Drillstem Tests with Same Temporary Completion String

Downhole Testing Tools in Extreme Environments

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