Drilling Technology Research Articles

Safe and efficient drilling and completion technology for deep shale gas in Sichuan and Chongqing

The world is rich in coalbed methane (CBM) resources and has broad exploration and development prospects. In this paper, first, the technical difficulties of drilling and completion in deep shale formations in the Sichuan and Chongqing region is systematically summarized. Second, a systematic evaluation was conducted on the optimization of temperature resistance performance and trajectory control technology of the rotary guidance system. Third, evaluation and economic analysis were conducted on the experimental effects of different technologies. Results show that: (a) the optimization technology for temperature resistance performance of integrated high-temperature resistant guide head and surface cooling equipment has been formed, which can effectively reduce the circulation cooling time and improve drilling efficiency. (b) Real time measurement of underground engineering parameters and monitoring and evaluation of wellbore cleanliness can reduce drilling risks, while achieving quantitative evaluation of drilling fluid gas content. (c) Assisted by real-time optimization technology of mechanical drilling speed based on underground surface engineering parameters, the acceleration effect has been significantly improved.

Hydraulically Fractured Horizontal Wells: A Technology Poised To Deliver Another Energy-Related Breakthrough of Enormous Scale

_ The development of efficient technologies for drilling and hydraulically fracturing horizontal wells has enabled the US to more than double hydrocarbon production since 2005 (Fig. 1), thereby providing unprecedented levels of energy security for America. America’s doubling of hydrocarbon output has also held down the price of energy worldwide, and by doing so, accelerated global economic growth. And it has helped reduce the greenhouse gas (GHG) intensity of energy production by backing out “dirtier” forms of energy, such as coal. Energy security—economic growth—reduced GHGs vented to the atmosphere: That’s a winning combination. One that America and many other countries have benefitted from immensely. Given the enormous positive contributions, it is worth noting that 20 years ago, few if any in our industry foresaw the immense potential of this technology, seeing it as being only applicable for extracting gas from ultratight reservoirs like the Barnett Shale, if they were aware of the technology at all. This oversight caused many companies to wait too long before deciding to pursue unconventional reservoirs and caused several of the “shale gas” pioneers to be late in recognizing that hydraulically fractured horizontal wells (HFHWs) could also be successfully applied in liquid-rich plays such as the Eagle Ford and Permian Basin. These are plays that today deliver far more value than that derived from the gas-prone reservoirs that comprised the initial suite of targets. And while events have proven beyond a doubt that HFHWs are a powerful tool for economically extracting hydrocarbons from both gas-prone and liquids-rich unconventional reservoirs, it seems likely that many in our industry are overlooking a third significant application of this technology: The use of HFHWs to extract heat from the Earth’s crust that can be utilized to generate electricity. Old Story, New Horizon What makes this third application particularly compelling as an investment opportunity is that the primary physical challenge that needs to be overcome to achieve attractive rates of return is strikingly similar to that which the oil and gas industry had to surmount to make both gas and liquids-rich unconventional reservoirs economic. The key to success in all of these cases boils down to an ability to create via hydraulic stimulation a sufficiently large amount of conductive, connected, fracture surface area. With this, one can reliably expect per-well production rates to be economic given the extremely slow rate at which hydrocarbons—and heat—move through unconventional reservoirs and the hot, dry, basement rocks that contain the bulk of the world’s geothermal resources. That converting from vertical to horizontal well geometries was critical for unlocking the potential of unconventional hydrocarbon reservoirs is now obvious, with this switch having allowed petroleum engineers to increase per-well fracture surface areas by several orders of magnitude. This move increased per-well flow rates by similar amounts (i.e., from subeconomic flow rates from hydraulically fractured vertical wells (HFVWs) to flow rates of thousands of BOE/D from HFHWs.

Rig Automation Empowers Well Construction in Ecuador

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 216249, “Digital Innovation of Well-Construction Process in Ecuador Through Rig Automation,” by Karen Peña, Kevin Etcheverry, and Hugo Quevedo, SPE, SLB, et al. The paper has not been peer reviewed. _ Artificial intelligence (AI)-based digital drilling technology was implemented in two mature fields in Ecuador that represent 33% of the country’s oil production. The drilling campaign’s main strategy included the deployment of a novel automation solution on two rigs, resulting in the optimization of the well-construction process. In the complete paper, the authors present the results of implementation of a rig-automation solution applied to 20 wells in 2022. Scope of the Digital Solution The authors detail the validation, optimization, and implementation of a drilling software to automate work flows and the installation and commissioning of associated hardware components. The following key indicators and objectives were established: - Validation of drilling-software work flows - Achievement of a 75% average in automation control - Improvement of rate of penetration (ROP) by 5% - Reduction of pre- and post-connection times by at least 30% - Real-time tuning of parameters - Training of all personnel involved in the use of the drilling-software package - Installation and commission of hardware components Drilling-Software Implementation The digital solution is an advanced software system that brings automation capabilities to drilling rigs, analogous to the different levels of automation found in automobiles. By drawing a parallel to car automation, one can better understand the system’s functionality and benefits. Level 1 consists of task automation, comparable to automatic driving features such as cruise control. In this context, the drilling software takes on the role of automating specific tasks within the drilling process. Level 2 involves process automation, similar to a car’s ability to autonomously park itself. The digital solution automates selected processes in drilling operations that enable efficient and precise execution. Level 3 encompasses adaptive automation, akin to a self-driving car that dynamically adapts to its surroundings. The drilling software continuously analyzes the real-time conditions of the wellbore and suggests optimal drilling parameters based on proprietary algorithms that leverage the well-known DeTournay model principle. The drilling software actively controls four key rig machines: the drawworks, topdrive, automated driller, and mud pumps. The solution adjusts drilling parameters intelligently, optimizing the drilling process and improving overall efficiency and drilling stability.

Construction of an acoustic information transmission system of a horizontal directional drilling device

Currently, the constant growth in the volume of the horizontal directional drilling procedure dictates the improvement of the drilling technology and the technical requirements. One of the important technical requirements for the horizontal directional drilling device is the transmission of information about drilling parameters to the operator (depth, rotation angle, inclination angle). The solution to this problem is possible with the help of measuring systems installed inside the drilling head. Traditionally, in real drilling conditions, three communication channels are distinguished: electrically conductive, hydraulic and electromagnetic, each of which has some advantages and disadvantages. The use of acoustic waves excited in the internal space of the drilling head and propagating in the material of the drilling column to the receiver allows to eliminate the disadvantages of the listed communication channels and ensure the highest quality horizontal directional drilling procedure. The paper investigates the acoustic method of information transmission in a horizontal directional drilling device. An acoustic system for positioning a drilling tool has been developed, which provides the transmission of information about the coordinates of the drilling head. The acoustic channel of information transmission has been studied in terms of constructing its structural components: the design of the probe-transmitter (electromechanical transducer) has been developed, as well as the hardware of the system. In order to determine the requirements for the modulator-demodulator of signals of an acoustic information transmission channel, the propagation of an information package was simulated taking into account the resonant properties of the converter using the Multisim circuit simulation program. Thus, the use of an acoustic system for monitoring and transmitting information about the positioning of the drilling head makes it possible to abandon expensive contact methods for determining the position of the drilling head, which give point information and require a lot of time. The proposed acoustic information transmission channel allows for tight acoustic contact between the protective container and the drilling column to eliminate power losses, increases the efficiency of the device and reduces the loss of a useful signal during its propagation and also simplifies the operation of the device. As a result, the developed acoustic system provides an opportunity to perform the highest-quality horizontal directional drilling procedure with the necessary requirements for the volume of transmitted information and stability of operation in complex noise-signal conditions, which eliminates the disadvantages of previously used methods.

Reviewing the advancements in offshore drilling technologies in the USA and their global impact

This study provides an overview of the significant advancements in offshore drilling technologies within the United States and their consequential global impact. As the world's leading innovator in the energy sector, the USA has played a pivotal role in shaping the future of offshore drilling, pushing the boundaries of technological capabilities and fostering sustainable practices. The review begins by highlighting the evolution of offshore drilling technologies in the USA over the past decade. Innovations such as advanced drilling rigs, smart sensors, and real-time data analytics have revolutionized the industry, enhancing operational efficiency, safety, and environmental sustainability. These technological breakthroughs have not only increased the depth and reach of offshore drilling but have also significantly reduced exploration risks and minimized the environmental footprint. The global impact of these advancements is explored, emphasizing the ripple effect on international energy markets, geopolitical dynamics, and environmental stewardship. The USA's expertise in developing cutting-edge technologies has been instrumental in influencing global industry standards and best practices. International collaborations, knowledge exchange, and technology transfer have facilitated the adoption of these advancements in offshore drilling practices across the globe. Furthermore, the study addresses the role of regulatory frameworks and industry collaborations in shaping the trajectory of offshore drilling technologies. The USA's commitment to stringent safety and environmental regulations has set a benchmark for responsible offshore exploration, influencing other nations to implement similar standards. The study concludes by highlighting the future prospects and challenges in offshore drilling technologies. As the energy landscape continues to evolve, the USA remains at the forefront of research and development, driving innovation towards cleaner, more efficient, and sustainable offshore drilling solutions. The ongoing collaboration between industry stakeholders, government bodies, and research institutions is crucial for addressing emerging challenges and ensuring the continued positive global impact of USA's advancements in offshore drilling technologies.

Optimization of double layered horizontal directional drilled ground heat exchangers by water injection into the borehole

Ground Heat Exchangers (GHEs) drilled using Horizontal Directional Drilling (HDD) technology have been proven to be a cost-efficient way of installing ground source heat pump systems (GSHP). They can also be installed in places where conventional horizontal ground heat exchanger (HGHE) would not be possible e.g., due to lack of land.In this research, a double layered horizontal borehole was installed as a GHE in Saga City, Japan. The two holes had a diameter of 114.3 mm and a length of 59 m and 56 m, respectively, while reaching depths of 5 m and 9.5 m. A polyethylene pipe with an outer diameter of 60 mm was inserted as a borehole heat exchanger (BHE). In March 2022, a two days thermal response test (TRT) showed the influence of rainfall on the system. A numerical model developed in FEFLOW based on the GHE dimension and the region's geology was validated using the measured temperatures of the heat medium at the return point and outlet of the GHE during the TRT. The validated model was then used to carry out sensitivity analysis examining different conditions of water injection into the borehole. The result of the sensitivity analysis showed that water injection into the borehole can improve the performance of the system and reduce the temperature change of the heat medium. Varying the injection rate can improve performance to a certain degree and the injection point has a strong influence on the performance. The injection temperature was also found to play a role in the performance, but even high temperatures in the case of heating showed significant improvement. Lastly, the influence of permeability was investigated and showed that impermeable layers are more favorable for injection compared to permeable layers.

Functional Gels and Chemicals Used in Oil and Gas Drilling Engineering: A Status and Prospective.

Research into functional gels and chemicals and their applications represents a cutting-edge international field of study. For example, investigating how they can be applied in oil and gas drilling (and extraction engineering) and developing novel functional chemical materials for the oil field could provide innovative solutions and technological methods for oil and gas drilling and extraction operations. Through a literature analysis, this paper presents a review of the current research status and application scenarios of different types of functional gels and chemicals, both domestically and internationally. The classification and preparation principles of various functional materials are systematically outlined and the current applications of functional gels and chemicals in oil and gas drilling and extraction engineering are introduced. These applications include drilling and plugging, enhanced oil recovery, water plugging, and profile control. The formation mechanisms and application scenarios of different types of gels and chemicals are also analyzed and summarized, with a discussion of their prospects in oil and gas drilling and extraction engineering. We broaden the scope of functional gels and chemicals by exploring new application fields and promoting the development of different types of gels and chemicals in a more intelligent direction.

Simulation and Analysis of a Split Drill Bit for Pneumatic DTH Hammer Percussive Rotary Drilling

Reverse circulation impact drilling has the advantages of high drilling efficiency and less dust, which can effectively form holes in hard rock and gravel layer. As integral reverse circulation drill bits used in the conventional down-the-hole (DTH) hammers are only suitable for specific formations, the whole set of DTH hammer needs to be replaced when drilling different formations. In this paper, several types of split drill bits for different drilling technologies are designed. The flow field characteristics of one of the split drill bits is analyzed based on the computational fluid dynamics (CFD) method, with four technic parameters considered, which are input flow rate, number of inlet holes, angle of injection exhaust holes, and diameter of injection exhaust holes, respectively. Three parameters are selected as indicators to evaluate the rationality and performance of the split drill bit, which are injection exhaust hole outlet mass flow rate, ratio of the mass flow rate out of injection exhaust holes to the whole inlet mass flow rate, and maximum pressure at the upper end of the split drill bit. According to the CFD analysis results, the above four technic parameters influence the flow rate and pressure in different rules. Considering the injection capacity, pressure loss, and bit strength, inlet holes of 10, injection exhaust holes with an angle of 50°, and injection exhaust holes with a diameter of 12 mm are recommended to obtain ideal reverse circulation. Different types of split drill bits were manufactured, and drilling experiments were carried out in unconsolidated formations. The maximum drilling rate can reach 1.5 m/min in the drilling experiments. The split drill bit proposed in this paper exhibits excellent adaptability for reverse circulation drilling in loose formations.

Research on gas drainage technology and equipment of high-level directional drilling in coal mine

The gas overrun at the upper corners of the goaf and return air lanes has been restricting the development of China's coal mining industry. To solve the problem of over-limit gas concentration at the upper corners, the fundamental reason is to reduce the gas concentration in the "fracture zone" of the coal roof . At present, the most commonly used methods such as high extraction roadway, buried pipe extraction, and high-level drilling in the "fracture zone" gas control of the goaf have the disadvantages of excessive cost and heavy workload, and the drilling trajectory of conventional drilling rigs cannot be accurately positioned problem. Therefore,it is proposed to use high-position roof directional long drilling technology to replace traditional high-drainage roadway for gas control, and analyze the influence of directional drilling diameter, position, depth and other parameters on gas drainage efficiency. Based on the analysis of four drilling cases of the directional drilling rig ZYWL-13000DS of China Coal Science and Industry Group Chongqing Research Institute Co., Ltd. at 33 (4) 13 working face of Shuangliu Coal Mine, from the perspective of construction effect,the directional drilling is a more reasonable construction level 5-8 times the mining height above the roof is appropriate; the construction diameter should be as large as possible when conditions permit;when the drilling depth is 20m deep into the fissure zone, the pumping capacity will increase greatly, and with the construction of the mining, pumping Capabilities tend to stabilize. Compared with the traditional high-drainage road control effect, the use of directional long drilling technology for gas drainage can reduce the cost by more than 70% and shorten the effective construction period by more than 75%. It is finally verified that the use of high-directional directional long drilling technology can replace the high-drainage roadway for "fracture zone" gas drainage.

Research and application of drilling technology for grouting transformation in coal mine strata——Taking Huainan Zhangji Mine as an example

In order to solve the problem of water disaster in coal mining and realize the safe mining of working face, the drilling technology of grouting reconstruction in coal mine strata is studied, and the key parameters in grouting construction are optimized and determined. According to the characteristics of engineering implementation, the optimization design of drilling casing program, the optimization of drilling tool assembly, the preparation of multi-type drilling fluid and the optimization of drill bit are introduced to ensure the smooth implementation of the project. According to the trajectory design requirements, the landing point of the main hole drilled into the coal seam floor to control the limestone layer was calculated. The results show that the construction technology and technical method are suitable for the multi-branch horizontal grouting well project in coal mine, which achieves the safe and efficient drilling of grouting well in coal mine, and provides useful experience for the subsequent grouting well construction in this area.

Research and application of drilling technologies in junggar basin for neogene ultra-shallow horizontal wells

The ultra-shallow heavy oil reservoir in Chunfeng Oilfield has become an important position in increasing reserves and production. Vertical wells have low production and poor benefits. The development engineering technology of horizontal wells faces many technical problems. Aiming at the drilling problems of ultra-shallow heavy oil horizontal wells, research and application have been carried out from the aspects of drilling engineering optimization design and shallow soft formation trajectory control. Shallow heavy oil cementing and completion and key drilling and completion technologies suitable for the efficient development of ultra-shallow heavy oil in the Neogene of Junggar Basin have been formed. The field application results show that the technology has well supported the development of ultra-shallow heavy oil reservoirs and has accumulated many construction records, such as the shallowest vertical depth, the largest vertical ratio, and the shortest drilling and completion period. The new production capacity of 50 thousand tons has strongly supported the benefit and production increase of Shengli exploration area in the Junggar Basin.

Drilling technology of long horizontal section of shale oil

As an important supplementary energy resource, shale oil has attracted worldwide attention due to its huge reserves and rich comprehensive utilization levels. The world is rich in oil shale resources. According to statistics, if the oil shale of 33 countries and regions in the world is converted into shale oil, it will be about 400 billion tons. With the continuous maturity of horizontal well drilling and completion technology in shale oil gas reservoirs and the application of other advanced technologies in horizontal well drilling, mature shale oil gas drilling and completion matching technologies have gradually formed at home and abroad after years of research and drilling practice. In terms of measurement technology, China has been able to produce single-point, multi-point, wired, wireless inclinometers and MWD measuring instruments while drilling and has mastered their usage methods. In terms of control technology, various specifications and types of fixed-angle and ground-adjustable curved shell screw drilling tools have been produced in China. Large deformation analysis and trajectory prediction methods for lower drilling tool assemblies have been completed. Various lower drilling tool assemblies and their usage processes required for wellbore trajectory control have been improved and mastered. In the construction of inclined and horizontal sections, attention should be paid to the response law of drilling tool combinations to drilling pressure in different formations, especially the response law of composite drilling. Reasonable drilling tool combinations should be selected for the control of wellbore trajectory in stable and horizontal sections, especially in the long stable and horizontal sections.

Research on Off-Line Programming Technology of NC Robot Drilling

Research on Off-Line Programming Technology of NC Robot Drilling

Research and application of low oil-water ratio organoclay-free oil-based drilling fluid technology

This paper introduces the formation and application of a low oil-water ratio organoclay-free oil-based drilling fluid. Shale oil and gas are important alternative energy sources. Due to the extremely complex geological conditions, oil-based drilling fluid technology is commonly used to reduce complexity. Although some achievements have been made, there are still problems such as unstable wellbore, difficult rheological control, and high cost. A stable and low-viscosity water-in-oil emulsion system was successfully prepared by using optimized fatty acid imidazolines emulsifier and alkyl alcohol ether wetting agent, which enabled the oil-based drilling fluid to have a larger solid and water phase capacity. On this basis, a special poly-fatty acid amide rheological modifier was used to assist in the regulation of rheological parameters, resulting in a low-viscosity and high-shear structure of the oil-based drilling fluid. This effectively ensured the efficiency of cuttings carrying while reducing the adverse effects of viscosity on Equivalent Circulating Density(ECD). The low oil-water ratio oil-based drilling fluid technology has been applied in a shale gas drilling platform in southern Sichuan, China, which greatly reduces the cost of oil-based drilling fluid while ensuring drilling efficiency.

Research progress of key technologies for drilling and completion of ultra-deep oil and gas production

Research progress of key technologies for drilling and completion of ultra-deep oil and gas production

Sealing method and experimental study of large-diameter reverse circulation hole hammer

A reliable sealing structure is the key to achieving reverse circulation drilling technology for large- diameter reverse circulation down the hole hammers, and it is also a difficult point in the design of large- diameter reverse circulation down the hole hammers. The existing large-diameter reverse circulation down the hole hammers are designed based on the sealing structure of the bottom drilling tool body. This article proposes a joint sealing method for hole bottom and hole opening. Based on this sealing method, a bundle type reverse circulation down the hole hammer and hole opening sealing device with a diameter of 710/311mm were developed for hole expansion, and field tests were conducted with a double wall drilling tool with a diameter of 127/70mm. The method achieved good continuous reverse circulation slag removal effect, with an average mechanical drilling speed of 2.1m/h, which is 2.6 times higher than the conventional roller bit hole expansion method. The experimental results indicate that the joint sealing method between the bottom and the mouth of the hole is feasible and worthy of further promotion and application.

Research and practice of high-speed spiral composite drilling technology in complex and weak coal seams

In response to the difficult slag discharge and low hole formation rate encountered in the Wangpo Coal Mine, a study was conducted on high-speed spiral composite drilling technology. This study was integrated with the performance characteristics of the ZDY6000LR-type high-speed pit rig, resulting in the design of drill bits in three different specifications: Φ110/63.5 mm, Φ95/60.3 mm, and Φ88/50 mm. Additionally, the study optimized the three-wing drill pipe's feed speed, rotation speed, and airflow volume. The industrial field test, conducted on the 3206 working face of the Wangpo Coal Mine, resulted in the design of three drill bit combinations that exhibited high strength and stiffness. This design improvement led to enhanced hole integrity, elevated slag removal efficiency, and extended service life for both the drill pipe and bit. The high-speed spiral composite drilling technology, alongside the supporting equipment, effectively addresses the challenges of slag discharge and nozzle top drilling encountered during operations. It significantly improves the deep hole drilling rate, achieving a drilling depth of over 100 m with a success rate exceeding 70%. This technology provides vital support for the extraction of gas from coal seams within the mine. Notably, the Φ95/60.3 mm screw pipe and its corresponding drill bit demonstrated the optimal holeforming effect, with an average hole depth of 111.2 m and a hole formation rate of 90.9%. These findings offer valuable insights for drilling operations under similar conditions of complex and weak coal seams.

Analysis of enhanced oil recovery using radial drilling technology

The study considers the radial drilling technology, which is used to increase the oil recovery factor in fields in the late stage of development. The composition and technical characteristics of the radial drilling unit are described, recommendations for radial drilling (RD) are given. The paper presents the test results of the technology in the conditions of the Perm Territory and the Republic of Uzbekistan, indicating its high efficiency.

Testing method of rock structural plane using digital drilling

The rock mass consists of rock blocks and structural planes, which can reduce its integrity and strength. Therefore, accurately obtaining the characteristics of the rock mass structural plane is a prerequisite for evaluating stability and designing supports in underground engineering. Currently, there are no effective testing methods for the characteristic parameters of the rock mass structural plane in underground engineering. The paper presents the digital drilling technology as a new testing method of rock mass structural planes. Flawed rock specimens with cracks of varying widths and angles were used to simulate the rock mass structural planes, and the multifunctional rock mass digital drilling test system was employed to carry out the digital drilling tests. The analysis focuses on the variation laws of drilling parameters, such as drilling pressure and drilling torque, affected by the characteristics of prefabricated cracks, and clarifies the degradation mechanism of rock equivalent compressive strength. Additionally, an identification model for the characteristic parameters of rock mass structural planes during drilling is established. The test results indicate that the average difference of the characteristics of prefabricated cracks identified by the equivalent compressive strength is 2.45° and 0.82 mm, respectively. The identification model while drilling is verified to be correct due to the high identification accuracy. Based on this, a method for testing the characteristic parameters of the surrounding rock structural plane while drilling is proposed. The research offers a theoretical and methodological foundation for precise in situ identification of structural planes of the surrounding rock in underground engineering.

Analytical and semi-analytical methods for modeling liquid inflow to a horizontal well (review)

The efficiency of using horizontal drilling technology largely depends on a number of factors, including the geological structure of the productive formation, fracturing, anisotropy, heterogeneity, porosity, and permeability. This necessitates the design of the process of oil inflow to the horizontal section of the well. The article presents analytical and numerical methods used in modeling liquid inflow to horizontal and multilateral wells. The main attention is paid to taking into account the anisotropy of reservoir permeability, the trajectory of the horizontal wellbore and hydraulic pressure losses due to friction.