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Well drilling in permafrost regions: dynamics of the thawed zoneстатья
Дата последнего поиска статьи во внешних источниках: 8 декабря 2021 г.
- Авторы: Eppelbaum Lev, Kutasov Israel
- Журнал: Polar Research
- Том: 38
- Год издания: 2019
- Издательство: Norsk Polarinstitutt/Norwegian Polar Institut
- Местоположение издательства: Norway
- Первая страница: 1
- Последняя страница: 8
- Номер статьи: 3351
- DOI: 10.3402/polar.v38.3351
- Аннотация: In cold regions, warm mud is usually used to drill deep wells. This mud causes formation thawing around wells, and as a rule, is an uncertain parameter. For frozen soils, ice serves as cementing material, so the strength of frozen soils is significantly reduced at the ice–water transition. If the thawing soil cannot withstand the load of overlying layers, consolidation will take place, and the corresponding settlement can cause significant surface shifts. Therefore, for long-term drilling or oil/gas production, the radius of thawing should be estimated to predict platform stability and the integrity of the well. It is known that the physical properties of formations are drastically changed at the thawing–freezing transition. When interpreting geophysical logs, it is therefore importantto know the radius of thawing and its dynamics during drilling and shut-in periods. We have shown earlier that for a cylindrical system the position of the phase interface in the Stefan problem can be approximated through two functions: one function determines the position of the melting-temperature isotherm in the problem without phase transitions, and the second function does not depend on time. For the drilling period, we will use this approach to estimate the radius of thawing. For the shut-in period, we will utilize an empirical equation based on the results of numerical modelling.
- Добавил в систему: Лев Виленович Эппельбаум