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Abstract One of the features of the drilling in YaNAO area is the long section of permafrost. This feature impacts on different technological processes of well constructing. Drilling fluid cools in the annular opposite permafrost without circulation in particular. This feature should be considered in the development of the mud program with oil based muds. Non-aqueous based fluid is the drilling fluid of choice to drill ERD wells. They make it possible to drill long sections even with the unstable formations. But they have some features, such as quite high rheology and its temperature dependence. The oil-based mud formulation which allows to decrease temperature dependence of rheology was applied in April – July of 2011 on Yurkharovskoye field. Lab research, extensive computer modeling and hydraulic simulations were performed to take into account temperature and pressure conditions of the north of YaNAO. Main features and results of the new OBM formulation field application are described. Comparative data of the rheology-temperature profiles of formulations used in other regions of Russia are presented in the paper. The experience of new OBM formulation application in ERD drilling on Yurkharovskoe field provided in the paper can assist with planning and project execution of OBM implementation in Arctic areas.
The magnetorheological fluids (MRF), or magnetic field responsive fluids, are a combination of magnetically polarizable particles in a carrier fluid. This type of fluid has the ability to modify their rheological properties under the influence of a magnetic field. The generation of a tunable pressure drop could have the potential to controlling fluid losses while drilling and cementing in narrow operating windows and to provide a tunable fluid barrier that could work as a packer. Using the reduced form of the Navier-Stokes equation and a model to estimate the yield stress of the fluid based on the magnetic field strength, it is possible to determine the pressure drop caused by the fluid behavior.
Khvoshchin, P. (Lukoil-Engineering Limited PermNIPIneft Branch Office ) | Lyadova, N. (Lukoil-Engineering Limited PermNIPIneft Branch Office ) | Iliasov, S. (Lukoil-Engineering Limited PermNIPIneft Branch Office ) | Nekrasova, I. (Lukoil-Engineering Limited PermNIPIneft Branch Office ) | Garshina, O. (Lukoil-Engineering Limited PermNIPIneft Branch Office ) | Kuznetsov, A. (Lukoil-Komi)
The pdf file of this paper is in Russian.
This work is devoted to the solution of the problem of well drilling on the sediments of the Devonian system known to lots of the world and Russian oil-and-gas regions. The well drilling on the Devonian sediments, especially with the horizontal borehole, is difficult due to the lithological composition and peculiar geomechanic properties of the clay formations composing the drilling intervals. This work covers the approach to solving the problem of keeping the Devonian sediments stability, starting from the integrated study of core of the problem intervals through the end of the testing of the developed technology concepts.
Hydrocarbon-based muds and relating invert emulsions are concerned to be unsurpassed in terms of keeping borehole stability, nevertheless they have got some disadvantages concerning the significant change in their structure-rheological properties during the change in thermobaric conditions. The solution of the stated problems is in the usage of the reagent, described in this report, which is aimed to regulate the rheological profile of the system under high bottom-hole temperature conditions. Due to the nano-size of the polymer particles, contained in the reagent, the filter cake is formed to colmatage micropores and microfractures in the formations as well as to prevent their spread.
The work covers the results of the practical-field testing of the improved invert-emulsion drilling mud formula at Kharyaginskoe oilfield. The leading foreign service company that conducted the drilling mud during the building of the horizontal wells at this oilfield before, has faced the problem connected with the loss of bore hole walls stability while opening the Devonian sediments at the zenith angles more than 60 degrees. The use of the drilling mud formula, presented in the report, has given the opportunity to avoid the problems stated above.
The field testing results, presented in the report, can be useful for the choice and reasoning of the drilling mud formula while constructing horizontal wells on the Devonian sediments by other companies especially those of them working in the Komi Republic and in the Nenets Autonomous District.