Optimization of Hot-Water Drilling in Ice with Near-Bottom Circulation

Hot-water drilling in ice with near-bottom circulation is more advantageous than traditional hot-water drilling with all-over borehole circulation in terms of power consumption and weight. However, the drilling performance of this type of drill has been poorly studied. Initial experiments showed that drilling with single-orifice nozzles did not proceed smoothly. To achieve the best drilling performance, nozzles with different orifice numbers and structures are evaluated in the present study. The testing results show that a single-orifice nozzle with a 3 mm nozzle diameter and a nine-jet nozzle with a forward angle of 35° had the highest rate of penetration (1.7–1.8 m h−1) with 5.6–6.0 kW heating power. However, the nozzles with backward holes ensured a smoother drilling process and a larger borehole, although the rate of penetration was approximately 13% slower. A comparison of the hollow and solid thermal tips showed that under the same experimental conditions, the hollow drill tip had a lower flow rate, higher outlet temperature, and higher rate of penetration. This study provides a prominent reference for drilling performance prediction and drilling technology development of hot-water drilling in ice with near-bottom circulation.

Progress and development of particle jet drilling speed-increasing technology and rock-breaking mechanism for deep well

Increasing drilling speed and efficiency of hard formation for deep and ultra-deep well is one of the international recognized drilling problems and key technologies to be tackled urgently. Particle jet impact drilling technology is an efficient non-contact rock-breaking method to overcome slow drilling speed, which has great development and application potential in drilling speed-increase of hard formation and deep well. High efficiency drilling technology and rock-breaking speed-increase mechanism in high temperature, high pressure and high hardness formations of deep and ultra-deep wells were mainly focused and keynoted in this paper. With extensive investigation of domestic and foreign literature, the working principle, key technical devices, deep-well-rock mechanical characteristic, unconventional constitutive model and rock-breaking mechanism of particle jet impact drilling technology were analyzed, which proved the feasibility and high efficiency for deep and hard stratum, and also, dynamic failure mechanism of rock needs to be elaborated by constructing the constitutive model with high temperature and pressure. Meanwhile, the major problems to be solved at present and development direction future were summarized, which mainly included: miniaturization of drilling equipment and individualization of drilling bit; optimization of jet parameters and the evaluation method of rock-breaking effect; establishment of mechanical property and unconventional constitutive model of deep-well-rock; rock-breaking mechanism and dynamic response under particle jet coupling impact. The research can help for better understanding of deep-well drilling speed-increasing technology and also promote the development and engineering application of particle jet impact drilling speed-increase theory and equipment.

Dual gradient drilling: a pilot test of decanter centrifuge for CAPM technology

The article is about problem of drilling deepwater oil and gas wells that consists in complicating and increasing cost of their well design due to narrowing mud window at different depths. The authors analyse drilling technology developed and applied in practice of offshore drilling with a dual gradient drilling, which allows drilling significant intervals without overlapping an intermediate casing string. Based on analysis of these technologies and taking into account their disadvantages the authors proposed and tested a new drilling technology of dual gradient drilling with placement of all necessary innovative equipment on drilling platform. Keywords: managed pressure drilling; deepwater drilling; offshore drilling; dual gradient drilling; riser; oil and gas exploration in sea.

Analysis of the deep drilling technology in unstable formations at the Semyrenky gas condensate field

The paper presents a general overview of deep drilling in unstable formations at the Semyrenky gas condensate field of the Dnipro-Donetsk Trough, including well design, bottom hole assemblies (BHA), drilling conditions, and drilling muds. Problems encountered during drilling for production casing of Wells 72- and 75-Semyrenky using high-speed drilling methods are analyzed. The relationships between the rate of penetration and disturbed rock stability, volume excess and depth, as well as consistent empirical patterns in changes in mud properties and depth are established. With these technical and economic performance indicators for well drilling are given, elements of a borehole stability management strategy were defined, the principles of mud selection for drilling through problem zones are validated. The paper discusses the requirements to a mud hydraulics program to reduce the erosion of borehole walls, specific borehole preparation techniques, such as reaming and gauging, for drilling in problem zones, and alternative options to ensure borehole stability. Keywords: borehole stability; statistical models; hole gauging; hole geometry; drilling mud; BHA.

Effects of Drilling Technology on Mini-Implant Primary Stability: A Comparison of the Mechanical Drilling and Femtosecond Laser Ablation

Objectives: Primary stability is a fundamental prerequisite in predicting the prognosis of a mini-implant (MI) as a skeletal anchorage. This study aims to evaluate the influence of implant site preparation technology on the primary stability of MI.Methods: A total of 108 bovine cortical bone samples were fabricated to three thicknesses (0.5, 1.0, and 1.5 mm). For each thickness group, the samples were divided into three subgroups: I (without site preparation), II (site preparation with a mechanical drill), and III (site preparation with femtosecond laser ablation). After MI insertion into these samples, the pull out strength of MI was measured by lateral pull out tests.Results: For the 0.5 mm thickness samples, the lateral pull-out strength was 9.9±2.7 N in subgroup I, 6.7±2.1 N in subgroup II, and 15.2±2.6 N in subgroup III. For the 1.0 mm thickness samples, the lateral pull-out strength was 39.3±2.5N in subgroup I, 38.2±2.7N in subgroup II, and 46.3±1.7 N in subgroup III. For the 1.5 mm thickness samples, the lateral pull-out strength was 73.9±4.8 N in subgroup I, 70.1±2.8 N in subgroup II, 75.0±2.2 N in subgroup III. No signs of carbonization or substantial cracking were visible in any of the bone samples.Conclusion: Site preparation with laser ablation significantly improved the lateral pull-out strength over mechanical preparation and control (no site preparation) in thinner cortical bone samples (1.0 and 0.5 mm). Such improvement in lateral pull-out strength decreases as the samples become thicker and diminishes in thick (1.5 mm) cortical bone samples.

FINITE ELEMENT ANALYSIS OF TOOLS FOR DEEP DRILLING TECHNOLOGY

Using the ANSYS software package, the issues of strength of the drill head and temperature distribution were considered, the design of a modern tool for deep hole drilling was analyzed, and modal analysis was carried out to exclude possible resonance phenomena.

Increase of dynamic stability of a basis at operation of the compressor equipment of the Abazіvka unit of complex gas preparation

The object of research is the basis of the compressor equipment of the complex gas treatment plant at the Abazivka field and the strengthening of the base soils with soil-cement elements, which are proposed to be arranged with the use of drilling technology. The research area is located on the territory of the current Abazivka Integrated Gas Preparation, near the village of Bugaivka, Poltava region, Ukraine. Abazivka Integrated Gas Preparation receives products from wells in Abazivka and Sementsivske deposits. It is proposed to carry out the reconstruction of Integrated Gas Preparation, which includes strengthening the foundation of the compressor model C1004-JGT/2-1 manufactured by «Propak» (Alberta, Canada). The amplitudes of oscillations of the compressor foundation were determined at a speed of 1400 rpm at the appropriate site with geological conditions. The magnitudes of oscillations and subsidence of the compressor foundation of the Abazivka complex of complex gas treatment were investigated experimentally. When determining the amplitudes of oscillations of the compressor foundations, only the amplitudes of oscillations in the direction parallel to the sliding of the pistons were calculated, and the influence of the vertical component of the perturbing forces was not taken into account. It is established that the amplitude of horizontal-rotational oscillations of the upper face of the compressor foundation relative to the horizontal axis exceeds the maximum allowable. It is substantiated that soil cement is a sufficiently strong and waterproof material that can be used to strengthen the base during the construction of equipment foundations. The possibility of application of the technology of application of soil-cement piles, made by brown-mixing technology for strengthening the base under the foundation of the compressor, is described and investigated. It is proposed to reinforce the base with rows of soil-cement elements, which will increase the modulus of deformation of the base, which is represented by loam, light to 14.3 MPa. In the case of strengthening the base, the amplitude of horizontal-rotational oscillations of the upper face of the compressor foundation is much less than the maximum allowable 0.1 mm. The subsidence of the foundation at reinforcement of the base, which does not exceed the maximum allowable value, is determined. Soil-cement elements are proposed to be arranged according to the drilling technology.

First Oman Implementation of Pressurized Mud-Cap Drilling Improves Drilling Efficiency and Sustainability

Drilling with a gas cap over the Natih formation in Oman often results in excessive flat time. Using the current dynamic fill equipment to deal with kick and loss scenarios leads to extensive nonproductive time on the rig. Managed pressure drilling (MPD) is a well-established drilling technology, and diverse variants exist to suit different requirements. All those variants use the rotating control device (RCD) as a common piece of equipment, but their procedures are different. The pressurized mud-cap drilling (PMCD) technique in the Natih formation replaces the need for traditional dynamic filling technology. The PMCD application enhances the drilling and completion processes by reducing flat time when total downhole losses are experienced. This paper elaborates on PMCD as a proven drilling technique in total loss scenarios when drilling with it for the first time in the Natih formation in Oman. It describes the PMCD process, the associated equipment, and the results of the inaugural application in the Qalah field.

New Steering Technology Using Pulsed Arc Plasma Shockwave: Plasma Pulse Steering Technology

Steering drilling technology can achieve precise control of wellbore trajectory, and related technologies have been widely used in the field of petroleum drilling. This paper proposed a new steering drilling technology based on the Pulsed Arc Plasma Shockwave Technology (PAPST),Plasma Pulse Steering Technology (PPST). PAPST transforms electric energy into mechanical energy by discharging electrodes, which can break rock. On the basis of PAPST, PPST can precisely control the discharge time and break the rock in the specified direction at the bottom of the well, so as to realize guided drilling. First, the discharge mechanism and guiding mechanism of the PPST were studied separately. Then, the discharge control model of PPST was established to explain the feasibility of using this technology to achieve drilling guidance. Finally, to verify the actual effect of this technology on rock breaking, an experiment was carried out with self-developed experimental equipment. Through the study of the mechanism and discharge control model of PPST, it is considered that it is feasible to use this technology to achieve guidance in theory. The experimental results show that the sandstone samples were damaged and a large area of pits appeared after the shockwave, and the ultrasonic penetration test results showed that there was damage inside the rock. As the number of impacts increased, the rock damage became more severe and fracture occurred. Therefore, it is feasible to apply PPST to the directional fracture of bottom hole rock. In summary, this technology has very good application prospects. For the first time, this paper proposed the idea of applying PAPST to steering drilling. Through the research on the steering mechanism and the experiment, the feasibility of this technology was proved and the theoretical basis was provided for the application of this technology in the field of oil drilling.