Coiled Tubing and Jointed Tubing Hybrid-String Well Intervention: Design, Testing, and Case History

We have developed a time-tracking test method for pressure buildup tests of horizontal wells to reduce the costs associated with testing wells. The time-tracking test method requires several tests that are performed chronologically from the midsection of the horizontal wellbore to the kickoff point. The purpose of time-tracking tests is to determine the production conditions of horizontal wells that allow the tests to be conducted at the kickoff point. Two horizontal wells associated within a sandstone oil reservoir were specifically chosen to determine how our time-tracking test method is to be implemented. The two wells had completely different production conditions. One had a small gas rate and a large water cut, whereas the other had a large gas rate and a small water cut. We recorded and analyzed the tested pressure data at numerous wellbore positions along the same horizontal well. Then, we interpreted the tested pressure data and compared the test results at different points along each well using the test curve shape and the interpretation parameter values. Through comparisons of the two wells, we found that the well-test curve shape and the interpretation results of tests performed above the kickoff point were completely different from those of the tests at the midsection of the horizontal wellbore under the conditions of a large gas rate and a small water cut. If a horizontal well has a small gas rate and a large water cut, the well can be tested at the kickoff point in the well using the wireline. We recommend that field petroleum engineers adopt the time-tracking test method to judge whether their horizontal wells should be tested at the kickoff point.

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Downhole Mixing Fracturing Method Using Coiled Tubing Efficiently: Executed in the Eagle Ford Shale

Lindsay

Flores

Ables

2012

All Days

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The increased demand for natural gas from shale plays in the US has forced the industry to be more efficient and develop innovative methods for fracture-stimulation optimization. Pinpoint-fracturing methods represent a divergence from the conventional methods with minimal optimization needed to help maximize reservoir volume. Multiple-interval completions can be performed efficiently so that all intervals receive the designed proppant volumes, one interval at a time. To accomplish this efficiency, coiled tubing (CT) is used to hydrajet perforate intervals for individual fracturing treatments at predesigned depths. Using various methods, CT depths can be corrected to actual depths, resulting in the precise placement of the perforations. Proppant plugs are used not only for isolating previously stimulated intervals, but also for maximizing the near- wellbore (NWB) conductivity necessary for long-term production performance. These fracturing methods do not require removing the CT from the well between treatments, and contingencies for early screenout can be remediated immediately with minimal impact to overall completion costs. Treating intervals individually substantially reduces the amount of hydraulic horsepower required onsite. The latest pinpoint-fracturing technique provides maximum engineering flexibility in the executionof these treatments by allowing downhole control of the proppant schedule; this can be used to optimize the stimulated reservoir volume (SRV) on- the-fly, in real-time, and with downhole control. The process also incorporates large-OD CT. A recent 25-interval completion in the Eagle Ford shale demonstrated the process and is discussed in this paper.

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Coiled Tubing and Jointed Tubing Hybrid-String Well Intervention: Design, Testing, and Case History

Cited by 4 publications

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Hydraulic Unit Equipment Features

Hydraulic Unit Equipment Features

Time-tracking tests and interpretation for a horizontal well at different wellbore positions

Downhole Mixing Fracturing Method Using Coiled Tubing Efficiently: Executed in the Eagle Ford Shale

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