Удосконалення теоретичних засад і технічних засобів для проведення спрямованих свердловин великого діаметру

Abstract

Дисертація присвячена удосконаленню теоретичних засад і технічних засобів для підвищення ефективності проведення свердловин великого діаметра з використанням двох породоруйнівних інструментів, а саме долота і розширювача. Для спрощення виконання розрахунку КНБК з двома породоруйнівними інструментами, розроблено методику яка складається з 4-х етапів і зводиться до їхнього циклічного повторення через певний інтервал. Запропоновано принципово нову методику проектування траєкторії свердловини. Ця методика передбачає максимальне використання природнього викривлення та застосування спрощених (неорієнтованих) компоновок низу бурильної колони. Для вимірювання величини ексцентриситету на розширювачі розроблено прилад у вигляді перехідника, який дозволяє визначити величину і напрям ексцентричного зміщення РШ відносно пілотного стовбура і зенітний кут свердловини в площині формування ексцентриситету.

Диссертация посвящена совершенствованию теоретических основ и технических средств для повышения эффективности проведения скважин большого диаметра с использованием двух породоразрушающих инструментов, а именно долота и расширителя. Для упрощения выполнения расчета КНБК с двумя породоразрушающего инструментами, разработана методика которая состоит из 4-х этапов и сводится к их циклического повторения через определенный интервал. Предложено принципиально новую методику проектирования траектории скважины, с участком бурения ствола большого диаметра в верхнем интервале. Эта методика предусматривает максимальное использование естественного искривления и применения упрощенных (неориентированных) компоновок низа бурильной колонны. Для измерения величины эксцентриситета на расширители разработан прибор в виде переводника, который позволяет определить значение и направление эксцентричного смещения РШ относительно пилотного ствола и зенитный угол скважины в плоскости формирования эксцентриситета.

The dissertation is devoted to the development of theoretical bases and technical means for increasing the efficiency of drilling large diameter wells using two rock cutting tools, namely, a bit and an underreamer(UR). In the construction of deep wells, it is often necessary to descent of casing strings with a diameter more than 324 mm at considerable depths. Therefore, it is necessary to drill large diameter borehole, in particular with diameters greater than 393.7 mm. The optimal solution is to use stepped bottom holeassemblance (BHA), that is, the BHA with two rock-cutting tools, namely the pilot's bore, to specify the direction of drilling and underreamer to form the main bore. The use of these BHA for drilling large diameter hole allows us to increase the technical and economic performance by increasing rate of penetration, which is associated with a smaller area of contact of each of the rock-cutting tools compared to the solid-state drilling method. The main condition for deepening the wells is the creation of an axial load on the whip, and in the case of using both the bit and the underreamer, it is necessary to determine the proportion of load that affects each of the rock-cutting tools. The main factors that influence the distribution of the load between the bit and the underreamer are their contact area with the rock, the number and diameter of the cutters on each of them, the number of teeth on the layers and the time of contact of the tooth with the breed. The difference of milling ability of the bit and underreamer, the differences in the area of their lateral contacting surfaces, as well as the difference in lateral forces on each of the rock-cutting tools, leads to an uneven lateral impact of the bit relative to the underreamer, and as a consequence of the appearance of an eccentric shift of the main bore relative to the pilot. This fact allows to control the trajectory of the wellbore due to the prediction of the work of a certain BHA. To simplify the calculation of the BHA with two rock-cutting tools, a four-step technique has been developed and reduced to cyclic repetition through a certain interval. The sequence of the calculation according to the methodology is as follows: determination of the distribution of the weight on the bit and underreamer, determination of lateral forces arising as a result of the change of stressed-deformedstate, determination of lateral forces that arise as a result of geological factors, calculation of the resulting lateral force, determination of the extentof eccentricity on the underreamer, determination of thecurving intensity and inclination angle. A fundamentally new method of designing a well trajectory with a section of large diameter in the upper range is proposed. This technique involves the maximum use of natural distortion and the application of simplified (non-oriented) BHA. The main idea of this technique is that the design of the trajectory of the well is carried out in the direction from the center of thebottom-hole target. This approach allows to determine the depth at which you need to change the type of BHA from the non-oriented to the oriented, and determine the optimum depth of completion of drilling intervalusing steppedBHA. In the course of well drilling, the hardness, the anisotropy of rocks and the angle of incidence of layers that make up its cut does not always coincide with those geophysical measurement that were carried out earlier on neightboring wells, the value of the actual diameter of the hole will be larger than the diameters of the rock-cutting tools, and the distribution of the weight on bit and underreamer may differ from the calculated values. This discrepancy will cause a difference in the actual eccentricity with the calculated value and, as a result, the wellbore will be drilled with a curving intensity that is different from the design. It is advisable to use a device that will allow the measurement of these parameters in the well drilling process, without the need for additional round-trip operations. To solve this problem, the device was developed as an adapter, which can be included in the stepped BHA directly under the underreamer and allows determining the azimuth and direction of the eccentric displacement of the UR relative to the pilot bore and the inclination angle of the well in the plane of eccentricity formation.