Average Penetration Rate Research Articles

Unexpected Wear of a Uniquely Designed Moderately Cross-Linked Polyethylene in Total Hip Arthroplasty.

A uniquely designed, non-heat-treated moderately cross-linked acetabular polyethylene liner used in total hip arthroplasty (THA) demonstrated excessive wear during routine follow-up, prompting an evaluation of the linear wear rate. All THAs were performed by the senior author. The study group included 38 THAs using the uniquely designed polyethylene in question, compared to a control group of 21 THAs using another moderately cross-linked polyethylene with good 10-year outcomes. Two-dimensional linear head penetration wear measurements were obtained using the Martell Hip Analysis Suite, and retrieval analysis was performed on two liners. The study group had a significantly higher average penetration rate of 0.089 mm/y than the control group average rate of 0.047 mm/y (P= .04). Forty-five percent of the study group had a wear rate above the osteolysis threshold (0.1 mm/y), compared to 24% in the control group. Macroscopic analysis of two retrieved liners validated the radiographic findings. The data suggest unexpectedly higher wear rates for a moderately cross-linked polyethylene design, with nearly half of the study group at risk for osteolysis. Further registry or database analyses of this particular moderately cross-linked polyethylene are warranted.

Performance analysis of utility tunneling data: A case study of pipe jacking in hard rock in Brittany, France

The increasing demand for renewable energy is accompanied with an urgent need for new and improved infrastructures worldwide, which in turn will require a greater number of utility tunneling projects in rock. Mainly due to tighter safety regulations, hard rock pipe jacking is getting increasingly important in the utility tunneling industry. Based on the example of the 530 m long Landivisiau utility tunnel case study, we present the first comprehensive pipe jacking study in high strength metamorphic rocks. The procedures and associated challenges of data analysis of a small-diameter pipe jacking project are presented and discussed. The tunnel has an outer diameter of 2.2 m and was excavated in Variscan basement rocks of Brittany. The geotechnical conditions at Landivisiau were very heterogeneous and stronger than expected, comprising fresh to highly weathered, weak to very strong gneiss, granite and schist with an UCS of up to 185 MPa. The TBM achieved an average advance rate of 17.3 mm/min and an average penetration rate of 3.4 mm/rev. The advance and penetration rates of the TBM are compared with results obtained by recent force estimation and penetration models. This study was conducted to raise awareness about the importance of using geological and technical data, to cope with increasingly strict controls by local authorities and to provide a foundation for further analysis and use of data, especially with respect to future automated tunneling.

Effects of Palm Leaf Ash and Palm Kernel Fibre on Properties of Compressed Laterite Earth Brick

This study was designed to compare the effects of the properties of compressed laterite earth brick (CLEB) stabilized with palm leaf ash (PKA) and palm kernel fiber (KPF). The study was carried out in Building Technology Department, Federal Polytechnic Bida, Niger State. Bricks of 222×110×70 were produced using manual pressed machine where nine bricks each were stabilized with palm kernel fiber for 1%, 2%, and 3%. Also 9 bricks each were stabilized with palm leaf ash for each percent 5%, 10% and 15%. The materials used were Palm Kernel Fiber, Palm Leaf Ash laterite soil, and water. The abrasion resistance test and water penetration test were carried out. The findings revealed that the water penetration rate for the CLEB bricks stabilized with PKF recorded average penetration rate of 10.18 at 1%, 11.52 at 2% and 12.19 at 3%. Only 3% produced higher penetration rate while CLEB stabilized with PLA recorded average water penetration rate of 11.58 at 5%, 10.63 at 10%, and 11.27 at 15%. All were in conformity with NBRRI specification of 12.5%. The abrasion resistance of the 28 day CLEB stabilized with PKF recorded average abrasion of 1.40 at 1%, 1.28 at 2% and 3.68 at 3%. All result were conformity with the NBBRI specification of 6.9. While the abrasion resistance of the 28 day CLEB stabilized with PLA recorded average abrasion of 2.39 at 5%, 2.22 at 10% and 2.32 at 15% which were in conformity with the NBBRI specification of 6.9. Based on the findings of the study, it was concluded that the CLEB stabilized with palm kernel fiber at 1% and 2% are in conformity with NBRRI specification of compressive strength, water absorption rate and abrasion resistance. While compressed laterite bricks stabilized with palm leaf ash should be improve to conform to NBRRI specification.

Plasma and Intrapulmonary Pharmacokinetics, and Dosage Regimen Optimization of Linezolid for Treatment of Gram-Positive Cocci Infections in Patients with Pulmonary Infection After Cerebral Hemorrhage.

PurposeThe objective of this study was to perform pharmacokinetics/pharmacodynamics (PK/PD) analysis of linezolid in patients with intracerebral hemorrhage and to provide suggestions regarding dosing and treatment regimens.Patients and MethodsTen patients with cerebral hemorrhage and pulmonary infection were enrolled in this study. Plasma and sputum samples were obtained at specific time points after the seventh infusion. Linezolid concentration was measured using HPLC, and PK parameters were calculated using the non-compartmental model. The probability of target attainment (PTA) and the cumulative fraction of response (CFR) in response to different dosing regimens (1200 mg/900 mg/600 mg/300 mg, q12h) were calculated based on the ratio of area under the curve to minimum inhibitory concentration (AUC/MIC).ResultsThe Cmax and AUC of linezolid were 12.89 μg/mL and 70.42 h·μg/mL for plasma, and 16.48 μg/mL and 92.95 h·μg/mL for sputum. The average penetration rate of linezolid in sputum, as represented by the ratio of AUC, was 131.99%. In response to the conventional dosing regimen (600mg, q12h), the PTA in the plasma or sputum was >90% only when MIC was ≤1 mg/L. Linezolid had the highest CFR against Streptococcus pneumoniae, followed by Enterococcus faecalis and Enterococcus faecium, with the lowest value for MRSA.ConclusionThis was the first study to evaluate PK/PD of linezolid in plasma and in the lungs of patients with cerebral hemorrhage and may assist in selecting appropriate dosing regimens for linezolid in these patients.

Mechanism research and field test of a novel axial vibratory tool for friction reduction in long horizontal wells

When drilling long horizontal wells, the axial vibration generated by the drilling string at the bottom hole will effectively alleviate the phenomenon of “frictional drag of the drill bit”, which can reduce the friction and enhance the penetration rate. Based on the principle of vibration impact, the axial vibratory tool for friction reduction with a diameter of 127 mm was designed, and the mechanical structure and working principle of this tool were also introduced in detail. First, the planar planetary motion of the throttle valve was described, and a model for calculating the cross-flow area at different moving valve and fixed valve sizes was established. Then, considering the effect of local head loss, the mechanical analysis of the working pressure drop generated by the fluid at each site within the dynamic short connector was carried out, and the relationship curves of the working pressure drop with time and cross-flow area were obtained. After that, the Viscous-Realizable k-ε turbulence model was used to simulate the water hammer pressure of the dynamic short connector, and the variation of water hammer pressure with time, cross-flow area, and cross-sectional flow velocity under 3D/2D conditions was obtained. Based on the undamped vibration differential equation, the axial impact force and axial vibration displacement generated by the vibratory tool were solved. The calculated results are in good agreement with the experimental test results. The field test of this vibratory tool was conducted in well FNHW4084 of the Mahu oil field in Xinjiang, China. The tool was in the well for 10.68 days. The drilling fluid was circulated for 202 h. The pure drilling time was 125.83 h. The drilling footage of a single tool is 596 m with an average penetration rate of 4.74 m/h. Rate of penetration in the test section was increased by 254% compared with the upper section. Compared with the same kick-off section of the neighboring well FNHW4026, the one-trip drilling footage of the test section was increased by 150% and the penetration rate was increased by 126%. The field test results present that this vibratory tool can significantly increase the drilling footage and penetration rate of horizontal kick-off section.

Big Data and Machine Learning Optimize Operational Performance and Drill-Bit Design

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202243, “Use of Big Data and Machine Learning To Optimize Operational Performance and Drill-Bit Design,” by Simon Cornel, SPE, Baker Hughes, and Gonzalo Vazquez, Senex Energy, prepared for the 2020 SPE Asia Pacific Oil and Gas Conference and Exhibition, originally scheduled to be held in Perth, Australia, 20–22 October. The paper has not been peer reviewed. Time savings and bit longevity are major challenges in coal-seam gas (CSG) unconventional fields onshore Queensland. Maximizing rate of penetration (ROP) on the basis of optimal drilling parameters was the key to tackling these issues. A formal process for optimizing performance was developed, with a focus on optimizing polycrystalline diamond compact (PDC) bit design and drilling hydraulics and developing a drillers’ road map. As a result, ROP increased from 50 to 150 m/h. Time savings of more than 150 hours for the drilling campaign was achieved. Background The drilling campaign encompassed two areas for development. Field A is a CSG acreage 45 km southwest, and Field E 30 km northeast, of Wandoan, Queensland. Eighty vertical wells would be drilled across the two fields. This would provide the opportunity to trial the data-mapping concept to increase ROP and fine-tune bit designs to improve longevity. In addition, the rig-sensor data set provided the basis for creating a machine-learning model to help improve drilling parameters during the production-drilling phase. Drilling Challenges The three primary challenges to be addressed included the following: - Economics for unconventional fields, specifically delivering time savings in order to lower the average cost per well - Control vibrations to avoid twistoffs and bottomhole-assembly fatigue - Consistent performance The benchmark for the initial project was an on-bottom ROP of 80 m/h. Therefore, the target for this campaign was to achieve an average on-bottom ROP of over 100 m/h and drilling-time savings of 1 hour per well. Methodology Bit optimization typically has been an iterative process, taking bit-record information to make assumptions about bit performance before providing recommendations for the next well. A more-detailed approach may include the use of log data (i.e., gamma ray and sonic) to estimate rock strength and overlay the depth-based well data to identify key incidents that affected performance (both positive and negative) so such incidents can be mitigated in future wells. This approach, while exhaustive, takes time to complete and is open to subjective interpretation of the engineer performing the analysis. When drilling CSG wells, typical well duration is 3–5 days. With short turn-around times between wells to analyze the data, the goal in this study was to develop an automated approach using real-time data gathered from the rig and present it to the field and rig crew in a visualized method. A two-step approach was devised in which data from the rig was used, followed by a real-time model.

Estimation of evapotranspiration in Eucalyptus plantation and mixed forests based on air temperature and humidity

Soil evaporation, Air temperature and humidity inside and outside the forest and river flows were continually monitored in eucalyptus plantations (EU) and coniferous broadleaved mixed forests (MFs) to investigate the reasons for the decreased runoff recorded in EU. The applicabilities of four estimation methods based on air temperature and humidity were evaluated and verified. Our results show that: (1) the average annual solar radiation penetration rate of the EU canopies was 1.75 times that of the MFs canopies, and temperatures were lower inside the two forests than outside the forests. The daily average temperatures inside the EU and MFs were 20.7 ℃ and 20.8 ℃, respectively, which were 1.5 ℃ and 1.4 ℃ lower than those outside the forests. The daily average relative humidity was 0.8% higher in the MFs than in the EU. (2) The evapotranspiration of EU and MFs accounted for 80.2% and 76.3% of the total rainfall respectively, of which the soil evaporation was 12.8% and 8.9% respectively, and the runoff production coefficients were 0.198 and 0.237 respectively. The main reason for the decrease of the EU production was that soil evaporation in EU was 43.8% higher than that in MFs. (3) The deviation of EU and MFs evapotranspiration (ET0) from the measured values was estimated by the ET0Valian(T, RH) and ET0Alt/rs(T, RH) methods as less than 10%. (4) Using the product of the extraterrestrial solar radiation and the surface solar emissivity of the forest instead of the extraterrestrial solar radiation in these four formulas, the variation trend of the estimated forest soil evaporation was highly similar to the measured value. ET0Valian(T, RH) and ET0Alt/rs(T, RH) had the highest accuracy in soil evaporation estimation (2.0–3.4% lower than the measured values). The results provide a theoretical basis for studying the ecohydrology of subtropical plantations in the Northern Hemisphere.

Optimized and Fast Drilling Technologies for Horizontal Shale Oil Wells in the Cangdong Sag

During the drilling of horizontal shale oil wells in the Cangdong Sag, the low ROP (Rate of Penetration), high safety risk, and uncertain cementing quality impeded the efficient exploration and development of shale oil. To address these problems, investigations were implemented on the detailed prediction of formation leakage pressure and collapse pressure. They were then carried out the optimization of casing programs and borehole trajectories and the personalized design of PDC bits. Further, the matching technologies such as brine drilling fluid, rotary steering drilling, ductile cement slurry, and floating displacement cementing were integrated, forming an optimized and fast drilling technology for the horizontal shale oil wells in the Cangdong Sag. This technology was applied in 20 horizontal shale oil wells in the Cangdong Sag, and the cementing quality was improved by 30.4%. For the wells with a depth of more than 4 500.00 m, the average ROP increased by 20.2%, and the average drilling cycle was shortened by 30.6%. For wells with a depth of lower than 4 500.00 m, the average ROP increased by 82.9%, and the average drilling cycle was shortened by 49.9%. These results demonstrated that the proposed technology could meet the requirement for the optimized and fast drilling of horizontal shale oil wells in the Cangdong Sag, providing a technical means for the efficient exploration and development of horizontal shale oil wells and also a reference for the drilling technology optimization of unconventional oil and gas reservoirs in the oilfields of China.

Research on the degree of coupling of the Internet development level and agricultural--Ecological efficiency based on 2009-2018 data from 13 major grain-producing areas in China.

Agricultural informatization and agricultural green development are important components of modern agricultural development, and coordination between the two is an important foundation for achieving sustainable agricultural development. This paper uses data from the 13 major grain producing areas in China from 2009 to 2018 to analyze the coordination of the Internet development level and the agricultural ecological-efficiency, and it further investigates the degree of coupling and coordination between the two. The results of theis study are as follows.(1) The Internet development level of China's 13 main grain production areas has been continuously improving. The average Internet penetration rate increased from 0.25 in 2008 to 0.54 in 2018. (2) The agricultural ecological efficiency of China's main grain production areas has gradually improved. The average value of agricultural ecological efficiency increased from 0.45 in 2009 to 0.79 in 2018. (3) The Internet development level in China's main grain production areas and the continuous improvement of coordination and degree of coupling of the agricultural ecological efficiency show that the interaction between them has led to continuous improvements in the agricultural informatization development and agricultural green development. However, the coordination between the two still has significant room for growth, and there is a certain gap between the different regions.

Intelligent decision method for main control parameters of tunnel boring machine based on multi-objective optimization of excavation efficiency and cost

Timely and reasonable matching of the control parameters and geological conditions of the rock mass in tunnel excavation is crucial for hard rock tunnel boring machines (TBMs). Therefore, this paper proposes an intelligent decision method for the main control parameters of the TBM based on the multi-objective optimization of excavation efficiency and cost. The main objectives of this method are to obtain the most important parameters of the rock mass and machine, determine the optimization objective, and establish the objective function. In this study, muck information was included as an important parameter in the traditional rock mass and machine parameter database. The rock–machine interaction model was established through an improved neural network algorithm. Using 250 sets of data collected in the field, the validity of the rock–machine interaction relationship model was verified. Then, taking the cost as the optimization objective, the cost calculation model related to tunneling and the cutter was obtained. Subsequently, combined with rock–machine interaction model, the objective function of control parameter optimization based on cost was established. Finally, a tunneling test was carried out at the engineering site, and the main TBM control parameters (thrust and torque) after the optimization decision were used to excavate the test section. Compared with the values in the section where the TBM operators relied on experience, the average penetration rate of the TBM increased by 11.10%, and the average cutter life increased by 15.62%. The results indicate that this method can play an effective role in TBM tunneling in the test section.

24‐4: Research on Water Vapor Penetration of OLED Encapsulation

This paper studied the characteristics of OLED encapsulation film, the test method of water vapor penetration and improving the ability of water vapor barrier. It was found that the group changes after hygroscopic, transferred to Si‐O bond. Based on this mechanism, the test method of water vapor penetration was studied. The average water vapor penetration rate P of film A and film B was about 0.14nm/h and 34nm/h respectively at 85 °C /85%RH environment by TOF‐SIMS and XPS test. At the same time, the permeability lag phenomenon was found. The enhancement effect of inter‐layer structure on water vapor barrier ability was further studied.

Using Crowd-Sourced Data to Assess the Temporal and Spatial Relationship between Indoor and Outdoor Particulate Matter.

Using hourly measures across a full year of crowd-sourced data from over 1000 indoor and outdoor pollution monitors in the state of California, we explore the temporal and spatial relationship between outdoor and indoor particulate matter (PM) concentrations for different particle sizes. The scale of this study offers new insight into both average penetration rates and drivers of heterogeneity in the outdoor-indoor relationship. We find that an increase in the daily outdoor PM concentration of 10% leads to an average increase of 4.2-6.1% in indoor concentrations. The penetration of outdoor particles to the indoor environment occurs rapidly and almost entirely within 5 h. We also provide evidence showing that penetration rates are associated with building age and climatic conditions in the vicinity of the monitor. Since people spend a substantial amount of each day indoors, our findings fill a critical knowledge gap and have significant implications for government policies to improve public health through reductions in exposure to ambient air pollution.

Similarity evaluation of stratum anti-drilling ability and a new method of drill bit selection

Considering the stratum anti-drilling ability, drill bit working conditions, drill bit application effect and drill bit economic benefits, the similarity of stratum anti-drilling ability was evaluated by grey relational analysis theory to screen out candidate drill bits with reference values. A new comprehensive performance evaluation model of drill bit was established by constructing the absolute ideal solution, changing the relative distance measurement method, and introducing entropy weight to work out the closeness between the candidate drill bits and ideal drill bits and select the reasonable drill bit. Through the construction of absolute ideal solution, improvement of relative distance measurement method and introduction of entropy weight, the inherent defects of TOPSIS decision analysis method, such as non-absolute order, reverse order and unreasonable weight setting, can be overcome. Simple in calculation and easy to understand, the new bit selection method has good adaptability to drill bit selection using dynamic change drill bit database. Field application has proved that the drill bits selected by the new drill bit selection method had significant increase in average rate of penetration, low wear rate, and good compatibility with the drilled formations in actual drilling. This new method of drill bit selection can be used as a technical means to select drill bits with high efficiency, long life and good economics in oilfields.

Shallow hot-point drill system for active layer temperature measurement along Zhongshan–Dome A traverse, Antarctica

AbstractIn glaciology, snow–firn temperature at 10 m is considered a representation of the mean annual air temperature at the surface (MAAT) of the studied site. Although MAAT is an important parameter in ice-sheet investigations, it has not been widely measured in Antarctica. To measure the 10 m snow–firn temperature in Antarctica, a shallow hot-point drill system is designed. In this simple and lightweight system, a hot-point drill can melt boreholes with a diameter of 34 mm in the snow–firn to a depth of 30 m and a temperature sensors string can measure the borehole temperature precisely. In the 2018/19 field season, 16 boreholes along the Zhongshan–Dome A traverse were drilled, and the borehole temperature was measured. Although certain problems existed pertaining to the hot-point drill, a total depth of ~244 m was successfully drilled at an average penetration rate of ~10 m h−1. After borehole drilling, ~12–15 h were generally required for the borehole to achieve thermal equilibrium with the surroundings. Preliminary results demonstrated that the 10 m snow–firn temperature along the traverse route was affected by the increasing altitude and latitude, and it decreased gradually with an increase in the distance from Zhongshan station.

Estimation of Penetration Rates of Floating Car Data at Signalized Intersections

Floating Car Data (FCD) are a largely used data source, particularly well established in delivering real time and average measurements of speed and travel time. They have the advantage of a spread coverage in space and time, being totally independent from any field device deployment. In the same time, they present the weakness of incomplete vehicle coverages, and more importantly unknown penetration rates. This weakness is the main limiting factor toward full scale uses of FCD such as determining traffic volumes. The direct way to obtain the penetration rate of a FCD dataset and capture its variations is to compare FCD counts with counts from a stationary device. The method has a spatial limitation since the penetration rate can be known only in particular locations where a continuous full-count detector is available. This paper suggests a novel methodology to estimate an average penetration rate at signalized intersections based on the comparison between probe-aggregated congestion density and an average congestion density supposed known. Trajectories are first aggregated on a signal cycle basis. Probe macroscopic conditions are then measured from the aggregated plot. A fundamental diagram model fitting is employed to empirically measure the congestion density. The feasibility of the method is tested on a commercial dataset of unknown penetration rate. The relevance and accuracy of the method are then examined under different conditions and scenarios with randomly extracted trajectories from a microscopic simulation. The results suggest that the penetration rate when higher than 5% can be estimated with an error below 10% for a sampling rate up to 15 seconds.

Drilling and completion technologies for deep carbonate rocks in the Sichuan Basin: Practices and prospects

The exploration and development of oil and gas resources in the Sichuan Basin is shifting to the deeper strata. The deep and ultra-deep wells in deep carbonate gas reservoirs are faced with many difficulties, such as multiple pressure systems, poor drillability, ultra-high pressure, ultra-high temperature and high sulfur content, which bring great challenges to drilling and completion engineering. In order to ensure the smooth exploration and development of deep carbonate oil and gas resources in the Sichuan Basin, the overall concept of combining field practice and technological research is followed. During the 13th Five-Year Plan, a batch of ultra-deep wells (well depth about 8000 m) have been drilled fast and safely (such as Well SYX133 in the Shuangyushi structure), and great progresses have been achieved in the experimental research of the support technologies in drilling and completion of deep and ultra-deep wells. And the achievements are as follows. First, the optimization of non-standard well structure, combined with the application of precisely managed pressure drilling technology and under-pressure plugging technology, lays a foundation for the optimized fast drilling and the safe reaching of geological targets. Second, a high-efficiency customized PDC drill bit is comprehensively optimized, popularized and applied, which effectively improves the average rate of penetration (ROP) in difficult-to-drill formations. Third, the development and application of drilling fluids (e.g. being resistant to high temperature of 200 °C and anti-composite brine) and active under-pressure plugging technology effectively reduces downhole complexities while drilling the complex formations, such as high temperature and high pressure brine and circulation loss. Fourth, when precisely managed pressure drilling and precisely managed pressure cementing methods are applied in the strata with a narrow density window, multiple pressure systems and pressure sensitivity, the average drilling and completion fluid loss is reduced by more than 90%, and the complexity treatment time is cut down by more than 85%, and the cementing quality pass rate is increased by more than 20%. Fifth, the integrated application of ROP improvement technologies and tools (e.g. air drilling) results in a great reduction of drilling cycle and cost. It is concluded that the experimental research achievements provide basic support for the fast development of natural gas resources in the Anyue Gas Field, Sichuan Basin, and the great discovery of the Permian and Devonian natural gas resources in the northwestern Sichuan Basin. What's more, in order to adapt to the development of the deep natural gas (over 9000 m) in the Sichuan Basin during the 14th Five-Year Plan, it is necessary to speed up researches on drilling and completion technologies in nine aspects, e.g. high-temperature downhole tools and working fluid.

A time-optimal wellbore trajectory design for slide drilling systems

For decades, the slide drilling system (SDS) has played a critical role in the area of directional drilling. Drilling in the sliding mode is much more time-consuming than drilling in the rotating mode for a SDS. Therefore, it generally takes more time to drill a curved wellbore segment than a straight segment of the same length. Based on this fact, a novel wellbore trajectory design for SDSs is proposed in this paper to reduce the total drilling time and improve economy. The basic idea of our strategy is to replace a long curved wellbore section, e.g., the build-up and drop-off sections, with a series of short circular-arc and straight-line segments in the design stage. Assuming that rotating and sliding modes are only used for straight-line and circular-arc segments, respectively, the total drilling time is reduced by increasing the average rate of penetration. Therefore, the problem lies in how to replace a long circular arc with multiple short circular arcs and straight lines to minimize the total drilling time, which is the aim of this research. In this paper, a piecewise trial strategy is proposed, where the optimized wellbore trajectory is generated by adding circular-arc and straight-line segments with equal length one by one according to the “line first” principle. This strategy converts the original optimization problem, which involves both combinatorial and parameter optimization of unknown dimension, to a much easier one, where there are only three design variables and one set of constraint equations. Due to the multimodal characteristics of the objective function, genetic algorithm (GA) is adopted to obtain the optimal solution. A great reduction of the drilling time is obtained by applying our method to two typical cases, which shows a clear potential for future field applications.

COMPARATIVE ANALYSIS OF PENETRATION RATES USING DOWNHOLE MOTOR AND ROTARY STEERABLE SYSTEM IN AN ONSHORE DIRECTIONAL HOLE

Directional drilling is a costly method used in drilling operations, as it requires investments in special tools such as downhole motor and rotary steerable system (RSS). This paper performs a comparative study between the penetration rates achieved when using downhole motor and RSS tools. To make the study feasible, the drilling of the 8 ¾ in diameter phase of an onshore directional hole, comprised between 197 m and 957 m, was analyzed using the equipment referenced. The average penetration rates and the costs generated by each one of them were calculated as a function of the total operating time. Considering these parameters, we found that the use of downhole motor was more advantageous than using the rotary steerable system because, despite its longer operating time, it presented much lower costs.

Prediction of unconfined compressive strength and deformation modulus of weak argillaceous rocks based on the standard penetration test

Standard penetration test is often used as an index for prediction of geomaterial elastic and strength properties. It consists of releasing a 63.5 kg hammer from a specified distance of 762 mm on a series of connected drill rods. The N-value is defined after a total 457 mm of penetration is achieved by counting the below counts for the last 300 mm of penetration. This required penetration is not often achieved in weak rocks due to their relatively large compressive strength. To eliminate the need for achieving a total required 457 mm of penetration, a novel approach is introduced where the rate of penetration of the split spoon sampler is used for the characterization of the engineering properties of the weak argillaceous rocks. The rate of penetration is defined as the slope of the final segment of the blow count versus penetration plot. The test results show that the average penetration rate at each test depth approaches a relatively constant value as the penetration increases. It is found that penetration rate is affected by the unconfined compressive strength, deformation modulus, and water content of the rock mass as well as the mean effective stress at the elevation of each test. Using in situ tests from 21 weak rock sites in Illinois, United States, models are proposed for the prediction of deformation modulus and unconfined compressive strength based on the penetration rate. The models account for the influence of mean effective stresses and the in situ water content of rock.

Using Adaptive Neuro Fuzzy Inference System to Predict Rate of Penetration from Dynamic Elastic Properties

Rate of penetration plays a vital role in field development process because the drilling operation is expensive and include the cost of equipment and materials used during the penetration of rock and efforts of the crew in order to complete the well without major problems. It’s important to finish the well as soon as possible to reduce the expenditures. So, knowing the rate of penetration in the area that is going to be drilled will help in speculation of the cost and that will lead to optimize drilling outgoings. In this research, an intelligent model was built using artificial intelligence to achieve this goal. The model was built using adaptive neuro fuzzy inference system to predict the rate of penetration in Mishrif formation in Nasiriya oil field for the selected wells. The mean square error for the results obtained from the ANFIS model was 0.015. The model was trained and simulated using MATLAB and Simulink platform. Laboratory measurements were conducted on core samples selected from two wells. Ultrasonic device was used to measure the transit time of compressional and shear waves and to compare these results with log records. Ten wells in Nasiriya oil field had been selected based on the availability of the data. Dynamic elastic properties of Mishrif formation in the selected wells were determined by using Interactive Petrophysics (IP V3.5) software and based on the las files and log records provided. The average rate of penetration of the studied wells was determined and listed against depth with the average dynamic elastic properties and fed into the fuzzy system. The average values of bulk modulus for the ten wells ranged between (20.57) and (27.57) . For shear modulus, the range was from (8.63) to (12.95) GPa. Also, the Poisson’s ratio values varied from (0.297) to (0.307). For the first group of wells (NS-1, NS-3, NS-4, NS-5, and NS-18), the ROP values were taken from the drilling reports and the lowest ROP was at the bottom of the formation with a value of (3.965) m/hrs while the highest ROP at the top of the formation with a value (4.073) m/hrs. The ROP values predicted by the ANFIS for this group were (3.181) m/hrs and (4.865) m/hrs for the lowest and highest values respectively. For the second group of wells (NS-9, NS-15, NS-16, NS-19, and NS-21), the highest ROP obtained from drilling reports was (4.032) m/hrs while the lowest value was (3.96) m/hrs. For the predicted values by ANFIS model were (2.35) m/hrs and (4.3) m/hrs for the lowest and highest ROP values respectively.