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Date submitted2020-07-02
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Date accepted2021-02-16
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Date published2021-04-26
Development of viscoelastic systems and technologies for isolating water-bearing horizons with abnormal formation pressures during oil and gas wells drilling
Article provides a brief overview of the complications arising during the construction of oil and gas wells in conditions of abnormally high and abnormally low formation pressures. Technological properties of the solutions used to eliminate emergency situations when drilling wells in the intervals of catastrophic absorption and influx of formation fluid have been investigated. A technology for isolating water influx in intervals of excess formation pressure has been developed. The technology is based on the use of a special device that provides control of the hydrodynamic pressure in the annular space of the well. An experiment was carried out to determine the injection time of a viscoelastic system depending on its rheology, rock properties and technological parameters of the isolation process. A mathematical model based on the use of a special device is presented. The model allows determining the penetration depth of a viscoelastic system to block water-bearing horizons to prevent interformation crossflows and water breakthrough into production wells.
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Date submitted2019-01-23
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Date accepted2019-03-17
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Date published2019-06-25
Development of the composition of the process fluid to eliminate bit seizure
- Authors:
- E. A. Rogov
During well construction, one of the most complicated types of accidents is the bit seizure as a result of which oil and gas companies incur significant losses due to the abandonment of a portion of the drill string in the well, cutting of an additional wellbore, and sometimes loss of the well. In the case of the elimination of seizure due to packing a positive result can be achieved by pumping portions of the process fluid into the seizure area. Destruction of the packer during the physicochemical effect of the process fluid, in general, allows for complete or partial softening of the packer, changing the pressure in the seizure area and significantly reducing the force required to release the stuck tool. The article presents the results of laboratory studies on the effect of various compositions of process fluids on the packer to eliminate the bit seizure. The effectiveness of the packer destruction was estimated by reducing the tangential stresses after the physicochemical effect of various compositions of process fluids for the same period. A 10% aqueous solution of hydroxyethylidene diphosphonic acid with an addition of 0.5% surfactant alpha olefin sodium sulfonate is recommended as a process fluid to eliminate packer seizures.