УТЯЖЕЛЕННЫЙ ИНВЕРТНЫЙ ЭМУЛЬСИОННЫЙ РАСТВОР С РЕГУЛИРУЕМЫМ РЕОЛОГИЧЕСКИМ ПРОФИЛЕМ ДЛЯ СТРОИТЕЛЬСТВА ГОРИЗОНТАЛЬНЫХ СКВАЖИН

Abstract

This article is devoted to the solution of the problem of well drilling on the sediments of the Devonian system. 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. The approach to solving the problem of keeping the Devonian sediments stability is considered. The results of the integrated study of core of the problem intervals, new formulas of invert emulsions and field tests are presented. Invert emulsions are 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 authors propose to use 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 article covers the results of the research and practical-field testing of new invert-emulsion drilling mud formulas at Kharyaginskoe oilfield which is situated on the territory of the Nenets Autonomous District of the Arkhangelsk Region within Timan-Pechora oil and gas bearing province (TPP). The use of the drilling mud formula, presented in the report, has given the opportunity to avoid the problems connected with the loss of borehole walls stability while opening the Timan-Sargaev sediments at the zenith angles more than 60 degrees. Due to the elimination of the time of the difficulties liquidation we managed to reduce the total time of horizontal well construction on the Devonian sediments more than 20 days.