Digital Drilling Research Articles

Experimental investigation of mechanical properties of structural interlayers for rock masses during drilling process

With the continuous development of underground engineering construction in China, it is particularly important to study the identification of structural plane characteristics of rock masses. In this study, three types of pseudo-rock specimens with structural plane interlayers were fabricated to analyze the patterns of drilling parameter changes in rock bodies with structural planes during the drilling process and to explore the characterization and identification methods of rock body structural planes. Gneiss, granite, and sandstone were used as rock materials, with gypsum mortar as the interlayer material for the structural planes in these three types of specimens. The indoor digital drilling equipment was utilized for conducting indoor digital drilling experiments. The variation patterns of drilling parameters in rock bodies with structural surfaces under different interlayer inclinations and thicknesses were analyzed. The relationship between the ratio of the change in rotational speed and drilling speed during the stable phase of the upper rock mass and the peak torque and peak drilling pressure has been established. The relationship between the structural plane inclination angle and the ratio of change in rotational speed and drilling speed has been determined. By utilizing the variation in these ratios, the impacts of the structural plane inclination angle and the thickness of the structural plane on the peak torque and peak drilling pressure have been elucidated. The research results provide a theoretical basis for the stability evaluation of rock masses with structural planes under drilling action.

Determination of elastic modulus and anisotropy for rocks using digital drilling method

The main purpose of this study is to provide a digital drilling-based method for determining rock elastic modulus and evaluating the anisotropy. By considering a concept of crushed zone, the drilling response was characterized as the function of specific energy and drilling strength. On this basis, an equivalent elastic modulus was proposed to evaluate the rock elastic modulus. Moreover, an anisotropy index was proposed according to the difference in specific energy under different borehole directions. Digital drilling experiments were conducted for three lithologies at drilling directions namely 0, 60, and 120° (Based on vertical orientation), revealing the anisotropic effect exhibited in the rock. To validate the measurement of rock elastic modulus and its anisotropy, the compressive tests under same conditions were carried out. The results suggested that the proposed indicator provided an accurate evaluation for the rock's elastic modulus, with an error margin of less than 10%. Drilling-based anisotropy is identified in the drilling response, especially the critical state between cutting and friction. The statical indicator CoV (coefficient of variation) was utilized to characterize the anisotropy along the borehole. This research's innovation lies in providing an approach to evaluating rock anisotropy and determining its elastic modulus by considering the drilling response.

The response mechanism and testing method of the rock elastic modulus while drilling

The elastic modulus is a basic parameter reflecting the deformation resistance and energy concentration characteristics of rock. The traditional testing method of the rock elastic modulus needs to core the surrounding rock and testing it in the laboratory, which has difficulty reflecting the rock mechanical properties under the engineering site environment, and uncontrolled broken surrounding rock is difficult to core for testing. Digital drilling technology provides a new idea for in situ testing of the rock’s elastic modulus. The key is to establish a quantitative relationship between the elastic modulus and drilling data. In this paper, the relationship between rock cutting energy density and drilling data is established, and a series of rock digital drilling tests are carried out. The response law of the drilling data and cutting energy density to the rock elastic modulus is clarified. The inversion model of the rock elastic modulus while drilling (DP-E model) is established. The verification test results indicate that the average difference rate of the test results based on the DP-E model is 7.06% compared with the compression test method, which verifies the effectiveness of the model. This study provides a theoretical basis for in situ testing of the rock elastic modulus.

Application of the drilling mechanical properties of rock to determine confining pressure in shallow geological formations

Confining pressure is an essential factor to consider in geological disasters in geothermal reservoirs and deep geological formations. Assessing the confining pressure holds practical importance, particularly in mitigating high-risk disasters associated with resource production. This study focuses on the development of a theoretical model for the mechanical properties of drilled rocks, specifically considering the impact of elevated confining pressure during the drilling process. Digital drilling experiments with different confining pressures are carried out to investigate the effect of confining pressure on the drilling mechanical properties of rock. A new method for identifying confining pressure and strength parameters using digital drilling is proposed. A comparison between the predicted confining pressure and the measured confining pressure is conducted to verify the accuracy of the model. The results show that the cutting force and the normal thrust at the cutting point increase with an increase in confining pressure. The drilling parameters (the bit rake angle a, the contact friction angle θ, the friction angle of rock φ, the cohesion of rock c, the effective stress generated by the drill torque St, the effective stress generated by the thrust along the normal axis Sn.) also increase gradually as confining pressure increases. Digital drilling technology offers shorter testing cycles and lower costs in comparison to traditional confining pressure testing techniques such as stress relief and hydraulic fracturing. The predicted confining pressure is consistent with the actual value. In summary, the method of determining confining pressure based on digital drilling has practical engineering significance.

Research on rockburst proneness evaluation based on interpretation of drilling parameters

Rockburst is one of the common geological disasters in underground engineering. Rockburst proneness evaluation is the premise of rockburst disaster prevention and control. It is an effective method to evaluate rockburst proneness by brittleness index. The traditional brittleness index testing requires coring the surrounding rock in the field and transporting it to the laboratory for testing. The testing process is inefficient and disconnected from the in-situ environment. The effective in-situ and accurate test of brittleness index has become a challenge. Digital drilling testing of rock mass is a new approach to solve the above problems and future research direction. The study explore a rockburst proneness evaluation method based on the interpretation of real-time drilling parameters. The key of this method is to establish the quantitative relationship model between the brittleness index and drilling parameters. Digital drilling tests on different rock types were conducted using the rock intelligent rotary cutting testing system (RCT system). The quantitative relationship between drilling parameters and rock strength parameters was analyzed. The drilling test model of rock equivalent brittleness index (DP-EBI model) is established. The verification test results show that the difference rate between the rock brittleness index with drilling test and indoor test is 11.8%. On this basis, the testing results of five rockburst evaluation methods, including equivalent brittleness index EBI, energy impact index ACF, potential energy of elastic strain PES, brittleness index modified BIM and dynamic failure time DT were compared. The effectiveness of using drilling parameters to evaluate rockburst proneness is verified. This study can provide a theoretical and methodological basis for the in-situ detection and evaluation of rockburst proneness and grade in underground engineering fields, such as mine roadways, transportation tunnels, and hydraulic tunnels.

Experimental study on quantitative drilling of composite rock mass

Effective identification of the interface position and characteristics of rock formations is important for identifying dangerous sources of structural deterioration in rock formations. To explore the sensitivity of the drilling parameters to changes in the formation characteristics and the influence of the interface on the drilling response of a composite rock mass, 28 test models with varying interface inclinations are designed. Laboratory quantitative drilling test research is conducted using the laboratory digital drilling test system at Shandong University. The influence law of the rock interface dip angle on the drilling parameters is established. Empirical equations for estimating the peak drilling pressure and peak drilling torque at the rock interface and the steady-state drilling pressure, drilling torque, and their differential values are established using multiple regression analysis. This study is expected to serve as a reference for improving digital drilling measurement accuracy.

Detection methods for strength deterioration and structural characteristics of fractured rock based on digital drilling

Fractures ubiquitously exist in strata, and large-scale fractures can cause low bearing capacity and poor stability in rock masses and can sometimes lead to hazards such as roof falls and collapses in mines and tunnels. The foundation of the control of surrounding rocks and effective prevention of such hazards is to be able to accurately determine the structural characteristics of fractures and strength parameters of rocks. Traditionally, testing is carried out mainly through indoor compression tests and borehole inspection, which require drilling of the surrounding rock on site and core testing indoors. The effective in situ and accurate detection of the structure and strength properties of surrounding rock has become a challenge. Digital drilling testing of rock mass is a new approach to solve the above problems and future research direction. In this study, a multifunctional rock mass digital drilling test system is used to perform tests on different types of fractured rocks. The response of drilling parameters to fracture parameters is analysed, and a strength deterioration evaluation index for fractured rock based on drilling parameters is established. Then, the response mechanism of the strength deterioration rate while drilling in the fracture zone is defined, and a model for identifying fracture parameters based on drilling is established. Furthermore, an in situ detection method for fractured rock properties based on digital drilling is proposed. The results of the validation test show that the average difference ratio between the equivalent compressive strength measured by the drilling test and the laboratory compressive test is 3.97 %. The strength degradation of the fractured rock is significant, with a maximum strength degradation rate of 82.1 % obtained through drilling. The average identification accuracies of the fracture position and width are 2.56 mm and 0.85 mm, respectively. The identification accuracy of rock properties while drilling is high, which proves the effectiveness of the prediction model while drilling. This study can provide a theoretical and methodological basis for the accurate in situ prediction of rock properties in underground engineering fields, such as mine roadways, transportation tunnels, and hydraulic tunnels.

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.

Effect of anisotropy on drilling mechanical properties for rock in process of drilling

The anisotropic characteristics of rock have important value for construction safety and evaluation of rock properties. The purpose of this article is to study the variation law of drilling parameters in different rocks and their anisotropy characteristics. This article investigates drilling characteristics by conducting digital drilling experiments on six different types of rocks in three different directions. The variation law of drilling parameters (drilling speed, torque, rotational speed, thrust force) and the special energy with drilling depth are analyzed as well as the anisotropy variation of six types of rocks. The influence of anisotropy on the specific energy of six types of rocks is investigated. A special energy index f is proposed to characterize the anisotropy for evaluating different rocks. The test results show that the anisotropy of granite, slate, gneiss, red sandstone, argillaceous sandstone, and sandstone is weakened accordingly by using the special energy index f. The specific energy index after data normalization can better judge the anisotropy difference for different rocks, such as granite, slate, gneiss, and red sandstone.

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.

Size effect of anisotropy in spatial variability of rocks: evaluation through digital drilling

Evaluating the anisotropy of rock and its size effect in spatial variation is of great significance for improving engineering efficiency and stability. For this purpose, an anisotropy index is used to quantify the magnitude of anisotropy in rock. Digital drilling tests are carried out in three directions on six types of rock to investigate the anisotropy of drilling parameters. The rock is subdivided into multiple small units along the depth of drilling, and the effect of size on rock anisotropy based on drilling work was studied. The research findings indicate that the drilling work on six rock types exhibits anisotropy, and the anisotropy sequence for the total drilling work of each rock is as follows: red sandstone > granite > slate > gneiss > sandstone > argillaceous sandstone. As the length of rock units increases, the anisotropy index of drilling work initially exhibits a fluctuating trend, subsequently reaching a state of stability, thereby manifesting a size effect. Furthermore, the representative elementary volume (REV) for each type of rock exhibits distinct variations. The anisotropy indices for drilling work along the depth of the borehole exhibit an initial phase of rapid increase, followed by a convergence towards a value close to 1.0. The anisotropy of rocks demonstrates size dependence, and size effects also exhibit anisotropy. Anisotropy and its size effects are interconnected and inseparable. The reliability of the cited anisotropy index is checked by comparison with two other anisotropy indices. This comparison shows that our method can reliably determine rock anisotropy. In summary, the research outlined in this paper presents a highly efficient and straightforward approach to evaluate the effect of size on rock anisotropy.

Characterizing rock transverse anisotropic spatial variations using digital drilling

Transverse anisotropy plays an important role in the engineering behavior of rock masses. This study examines the transverse anisotropic spatial variations and evaluates them using the coefficient of variation (CV) and anisotropy index (AI) through digital drilling tests. Four types of rocks, shale (SH), mudstone (MU), sandstone (SA), and schist (SC), are studied in four directions, revealing significant transverse anisotropy at the cutting point. The results demonstrate that the effect of the depth per rotation on the difference is weaker compared to the scaled weight and torque. The ranking of transverse anisotropy in the tested rocks is: MU > SA > SH > SC. Transverse anisotropy changes along the drilling depth vary across rock types. With the increase of drilling depth, SH experiences a decrease, rebound, and another decrease. MU shows an initial increase followed by a decrease. For SA, the degree of transverse anisotropy decreases and is sustained at a lower extent. SC exhibits slight fluctuations with the exception of the abrupt change. The time when the drilling bit is in perfect contact with the rock and the cutting efficiency in different drilling directions are the main factors causing the transverse anisotropy. The intricate evolution of transverse anisotropy should be worth investigating on a wider scale.

A new method for determining strength parameters of rock using digital drilling technology

Fast and accurate prediction for mechanical parameters of rock mass is an important prerequisite for guiding the safe construction of rock engineering. At present, the rock strength parameters test requires well-prepared samples; sample preparation is time consuming, costly, and difficult as well as destructive, in particular the polishing and rectification of the sample ends. In this paper, the mathematical model of the drilling process is established based on the force characteristics of the drill bit and the principle of mechanical limit equilibrium. The digital drilling tests are carried out on four types of rocks to drilling characteristics using the digital drilling system. The concept of cutting strength ratio is proposed to analyze the correlation between cutting strength ratio and rock internal friction angle and cohesion. A new method is proposed for determining the compressive and tensile strength of rock. The results show that the cutting strength ratio increases with the increasing of internal friction angle and cohesion. The uniaxial compressive strength and tensile strength of rock increase linearly with the cutting strength ratio. The average error of rock tensile strength is 12.29%, and the average error of uniaxial compressive strength is 20.44%. The internal friction angle of rock obtained based on the digital drilling technology is consistent with the value measured by the laboratory standard test. This method can provide a new way to determine rock strength parameters in real time.

Experimental Investigation on Anisotropy of Rocks Using Digital Drilling Technology

Accurate determination of rock anisotropy is of great significance for analyzing the safety and stability of engineering rock mass. In this paper, uniaxial compression tests are carried out on four kinds of rocks: slate, gneiss, sandstone and shale, to obtain the uniaxial compressive strength of each rock in the different directions. Digital drilling tests are carried out on four kinds of rocks to study the anisotropy of drilling parameters. According to the working principle of the drill bit, its force balance analysis model is established, and the concept of cutting strength ratio is proposed. Using the drilling parameters (drilling depth, drilling time, torque and thrust, etc.) in the different directions for each rock, the interrelationships between them are analyzed. The anisotropy index of rock is defined according to the ratio of cutting strength in different directions of drill parameters, and a new method for judging rock anisotropy is proposed. The results show that the thrust and torque in all directions of the rock increase with the drilling depth. The torque in all directions of the rock has a positive linear relationship with the thrust. The ranking of the anisotropy degree for the four types of rocks is as follows: gneiss > slate > shale > sandstone. The anisotropy results have been validated by an alternative method utilizing uniaxial compressive strength. The determination results are verified by the uniaxial compressive strength of the rocks, and the degree of anisotropy of the four rocks is consistent with the determination results. This method can help engineers analyze the anisotropy of rock, and provide a new idea for studying the integrity and stability of rock mass.

In situ digital testing method for quality assessment of soft soil improvement with polyurethane

This study purposes an in situ testing method on quality assessment of soil improvement. Factual drilling data includes the spatial distribution and in situ strength of untreated and treated soil along three different drillholes measured by on-site drilling monitoring method. These factual drilling data can characterize the degree of soil improvement by penetration injection with permeable polyurethane. Result from on-site drilling monitoring shows that the linear zones represent constant drilling speeds shown in the plot of drill bit advancement vs. net drilling time, which indicates the spatial distributions of soil profile. The soil profile at the study site is composed of four layers, which includes fill, untreated silty clay, treated silty clay, and mucky soil. The results of soil profile are verified by the parallel site loggings. The constant drilling speeds profile the coring-resistant strength of drilled soils. By comparing with the untreated silty clay, the constant drilling speeds of the treated silty clay have been decreased by 13.0–62.8%. Two drilling-speed-based indices of 61.2% and 65.6% are proposed to assess the decreased average drilling speed and the increased in situ strength of treated silty clay. Laboratory tests, i.e. uniaxial compressive strength (UCS) test, have been performed with core sample to investigate and characterize in situ strength by comparing that with drilling speeds. Results show that the average predicted strengths of treated silty clay are 2.4–6.9 times higher than the average measured strength of untreated silty clay. The UCS-based indices of 374.5% and 344.2% verified the quality assessment (QA) results by this new in situ method. This method provides a cost-effective tool for quality assessment of soil improvement by utilizing the digital drilling data.

IADC Code Upgrade: Interpretation of Surface and Downhole Data to Support Drilling Forensics

Summary This paper establishes drilling surveillance interpretation and monitoring techniques for digital drilling data which can be used to support drilling forensics and improve drilling performance. One significant advancement in the last 20 years has been the widespread availability and use of sensors to monitor all aspects of the drilling process. The majority of sensors will take surface and downhole data at several hundred samples per second, process the data, and store a record at one sample per second. The data from these sensors are collated and processed using some form of electronic data recording (EDR) system. The information is subsequently displayed in real time and stored for off-site transmittal. This paper extensively evaluates the impact on drilling performance due to how data from such sensors are collected and processed and the information is displayed. A number of observations are investigated, analyzed, and explained identifying how data quality, consistency, frequency, sensor errors, and data artifacts can skew the displayed results. This can critically impact the drilling forensic analysis and subsequent interpretation. Failing to account for these data quality issues in real time may mask drilling dysfunction, causing accelerated damage to the drill bit and drilling assembly. This paper also aims to highlight techniques for displaying and interpreting drilling data to enhance drilling performance as well as diagnose dysfunction during reviews of historic wells. Understanding these limitations in advance and incorporating them in a team’s surveillance strategy can help with the diagnosis of drilling dysfunction and aid performance improvement. These recommended practices have been developed to offer a foundation for drilling surveillance, interpretation, and monitoring as well as training for the industry. They have been created such that they can grow organically and may be used for developing subsequent industry publications. The work described in this paper is part of a joint International Association of Drilling Contactors (IADC)/Society of Petroleum Engineers (SPE) industry effort to revise the IADC dull-grade process.

Sensitivity analysis and rock strength prediction study of rotary drilling with drilling parameters

Rock property exploration has been a major focus in geotechnical engineering. Among various methods of engineering geological research, drilling exploration is significant. Extensive studies have been conducted on drilling exploration and the prediction of rock strength to investigate the interaction between machinery and rock during rotary cut borehole operations. Indoor drilling tests were conducted on rock materials and mortar materials using a self-developed rotary cut digital drilling system. The system enables comprehensive measurement of drilling parameters, including torque, rotation speed, displacement, drilling pressure, borehole sound pressure level, and water intake pressure. An orthogonal test design was used to evaluate the sensitivity between the subsequent drilling parameters and rock strength. The sensitivity analysis of variance (ANOVA) results showed that the speed of rig control parameters and initial push speed had different levels of influence on four parameter indicators: torque, rotation speed, drilling pressure, and sound pressure level. Particularly, the uniaxial compressive strength of the rock significantly affected all four parameter indices, with sound pressure level being the most sensitive and drilling pressure being the least sensitive. Particularly, the uniaxial compressive strength of the rock significantly affected all four parameter indices, with sound pressure level being the most sensitive and drilling pressure being the least sensitive. The model's validity and the sensitivity of the validated parameters were evaluated using the F-test and t-test methods. Comparative analysis of the predicted rock strength values and the measured values showed a difference rate of less than 10%, indicating the model's predictions were highly accurate and affirming its validity.

Effect of horizontal stress on fractal characteristics of rockburst fragments in coal mining

With the continuous increase in underground engineering depth, the risk of coal–rock dynamic disasters, such as rockburst, is becoming increasingly serious and complex threatening the safety of coal resources. To study the effect of horizontal stress on fractal characteristics of rockburst fragments in coal mining, this paper uses a digital drilling instrument to perform rockburst proneness tests on andesite and granite specimens with different horizontal stresses. Fractal theory is used to calculate the fractal dimension of the rockburst fragments for several combinations of parameters. The residual elastic energy index is combined with the fractal dimension of rockburst fragments to assess the propensity of rockbursts from macroscopic and microscopic perspectives. The experimental results show that the positive correlation between the fractal dimension and the AEF obtained under the two methods. The fractal dimensions of andesite and granite are 1.507–1.80 and 1.734–1.979, respectively. According to the rockburst proneness criterion, it is predicted that andesite and granite are all strong rockbursts under confining pressures of 20 MPa, 30 MPa and 50 MPa. Therefore, it is of some theoretical relevance to investigate the rockburst mechanism in terms of both the AEFand fractal dimensions of fragments under different unloading conditions.

Cutting energy characteristics for brittleness evaluation of rock using digital drilling method

The reliable evaluation of rock brittleness is essential in engineering geology for various applications, such as water conservancy, hydropower, transportation, energy exploration, and underground engineering development. This study proposes a new method for evaluating rock brittleness using a digital drilling approach. A cutting model was established to describe the relationship between the energy characteristics and mechanical parameters of the rock during the drilling process, accounting for the effects of friction and drilling fluid. Furthermore, a drilling-based index, the brittleness evaluation index (BEI), was developed to evaluate rock brittleness based on energy dissipation. We conducted drilling tests to investigate energy evolution, including cutting energy, friction energy, and liquid energy. The results indicated that cutting energy has a linear correlation with the strength parameters of rock, with a significant correlation coefficient. With increasing drilling depth, cutting energy and liquid energy exhibit a similar increasing trend, which initially remains constant and then increases linearly after a critical depth is reached. Friction energy rapidly increases with drilling depth at the beginning, and the growth rate decreases after reaching the critical point. Compared with the laboratory-determined brittleness index, our proposed method provides a reliable evaluation of rock brittleness. In summary, our study offers a practical approach to evaluating rock brittleness that could benefit various engineering applications.

Digitalization of hydraulic rotary drilling process for continuously mechanical profiling of siliciclastic sedimentary rocks

Hydraulic rotary drilling can offer the essential information and core samplesa for the researches on solid earth. Recording the factual field drilling data and analyzing the hydraulic rotary coring process are challenging yet promising to utilize the massive drilling information in geophysics and geology. This paper adopts the drilling process monitoring (DPM) technique and records the four parameters of displacement, thrust pressure, upward pressure, and rotation speed in real-time series for profiling the siliciclastic sedimentary rocks along 108 m deep drillhole. The digitalization results with 107 linear zones represent the spatial distribution of drilled geomaterials including superficial deposits (fill, loess, gravelly soil), mudstone, silty mudstone, gritstone, and fine sandstone. The constant drilling speeds varying from 0.018 to 1.905 m/min present the in-situ coring resistance of drilled geomaterials. Furthermore, the constant drilling speeds can identify the strength quality of soils to hard rocks. The thickness distributions of the six basic strength quality grades are presented for all the sedimentary rocks and each individual type of the seven soil and rocks. The in-situ strength profile determined in this paper can be used to assess and evaluate the in-situ mechanical behavior of geomaterial along the drillhole and can provide a new mechanical-based assessment for determining the spatial distribution of geological strata and structures in subsurface. They are important since the same stratum at different depths can have different mechanical behavior. The results provide a novel quantitative measurement for continuously in-situ mechanical profiling by digital drilling data. The findings of the paper can offer a new and effective method for refinement and upgrading of in-situ ground investigation, and can provide researchers and engineers with a novel tool and valuable reference to digitize and utilize factual data of current drilling projects.