Hydraulic Radial Drilling Using a Rotary Hydraulic Nozzle Aimed at Increasing the Exploitation of Deposits

Abstract

The exploration and development of new hydrocarbon deposits face increasing challenges, primarily driven by the shift away from hydrocarbons towards renewable energy sources like shallow geothermal deposits, wind farms, and photovoltaics. This shift necessitates finding solutions that minimize environmental impact and enable increased energy extraction from existing or decommissioned fields and wells. This paper explores the possibility of excavating from potentially depleted fields, where a significant portion (up to 85%) of the reservoir’s resources remain unrecoverable due to low reservoir energy. To address this, secondary and tertiary exploitation methods are proposed involving the supply of external energy to increase the pressure in the reservoir layer, thereby enhancing resource exploitation. One of the suggested tertiary methods involves reaming the deposit with multiple small-diameter radial holes using a hydraulic drilling nozzle. The entire process comprises several key components, including the coiled tubing unit (CTU), high-pressure flexible hose, window drilling kit for casing pipe, kit for positioning the exit of the hydraulic drilling head from the casing pipe, anchor, and hydraulic drilling head attached to the end of the high-pressure flexible hose. This method aims to increase the contact between the reservoir layer and the wellbore, potentially leading to an increase in or initiation of exploitation in certain deposit scenarios. The described method presents an environmentally friendly approach, eliminating the need for drilling new boreholes and offering cost-effective access to resources in decommissioned deposits with insufficient reservoir energy for self-exploitation. The applicability of this method to extract methane from coalbed seams is also mentioned in this article. In a separate article, the authors detail the design of a hydraulic drilling nozzle specifically for reaming the reservoir layer.

Hydraulic Drilling Nozzle Design and Research

“…However, knowledge of the maximum ranges of the fluid jets at the appropriate injection pressure emanating from the outlet holes of the rotary head with different hole diameters is essential. The method for determining the range of the fluid jet at which volumetric hydraulic fracturing of the tested rock formation still occurs is presented in the study [15]. The developed rotary hydraulic nozzle has been thoroughly investigated.…”

“…In the case of hydroabrasion, the focus is often on the energy consumed to create a fissure in the rock [11], expressed as the ratio of energy to the product of the depth and width of the fissure and the velocity during the fissure cutting process. In classical drilling, we refer to the total drilling energy TSE (total specific energy), expressed as the sum of the energy rotational motion, the movement of the drill string, and the hydraulic energy required to drill a unit volume of rock during the drilling process [12][13][14][15]. In the 1960s, a patent [16] was already granted for a drill utilizing the hydraulic energy of a liquid jet combined with the addition of abrasive material.…”

“…The openings in the interchangeable tips were made cylindrical with diameters of 0.4, 0.5, 0.6, 0.7, 0.8, 1.0 and 1.2 mm. The range of jets flowing out of the openings with different diameters was determined during the tests of the hydraulic fracturing efficiency of the test head equipped with one central front opening and six openings made on the side of the cylinder, into which tips with appropriately calibrated diameters of outlet openings were screwed [15]. Given the jet range obtained during the tests of the jet flow from openings of varying diameters, the maximum point is determined along the red line, where the energy of the jet flowing out of the opening allows for volumetric rock hydraulic fracturing, as shown in Figure 3.…”

“…The maximum range of the jet flowing out of the designed opening and its projection onto a plane parallel to the cross-section in a direction perpendicular to the axis of the rotating head allow for the determination of the effective range of the jet and the radius from the axis of the rotating head to the diameter of the propagated hole. The design of the rotary head begins by assuming an angle of inclination of the outlet hole 1 with respect to the axis of the rotary head and along line A at the chosen angle plotting a line with the length of the stream reach allowing volumetric mining of the rock equal to 10 cm for a given diameter of the outlet hole (in our case it is a 0.8 mm diameter hole at a discharge pressure P = 40 MPa [15]). Then, from a point 10 cm away on line A from the head face, The maximum range of the jet flowing out of the designed opening and its projection onto a plane parallel to the cross-section in a direction perpendicular to the axis of the rotating head allow for the determination of the effective range of the jet and the radius from the axis of the rotating head to the diameter of the propagated hole.…”