Geochemical Evaluation of Formation Water, Mauddud Reservoir, Khabbaz Oilfield, Kirkuk Area, Northern Iraq

In this study, formation-water samples were collected by NOC Staff, during drilling time, from the Mauddud Formation reservoir of the Khabbaz Oilfield, for this reason four samples from four wells; Kz-3, Kz-4, Kz-7, and Kz-23 were selected to geochemical analysis. Analyzed geochemical parameters include TDS and the concentrations of the different dissolved cations and anions present in brines (Ca+2, Mg+2, Na+1, SO4-2, Cl-1, HCO3-1, and NaCl). Variations among the resulted data are discussed by comparison with other Cretaceous Brines. Geochemical ratios of Na/Cl, (Na-Cl)/SO4) and (Cl-Na)/Mg+2 was calculated for formation water classification following Bojarski, (1970). The calculated geochemical ratios of the studied samples in the studied four wells indicate that all of these waters are "chloride calcium" type under subsurface conditions, this type reflect closed system isolated associations reservoir, which are becoming high hydrostatic in deeper zones without influence by infiltration waters. A major transversal fault cutting the structure at its SE plunge had participated in the dilution of the Mauddud reservoir brine effectively.

Conceptual Control Method of Drilling Rig’s Torsional Vibrations Frequencies

This article focuses on the possibility of using an innovative drilling method for the implementation of underground works, especially where there is no physical possibility of using large working machines. Work on a model carried out under the INDIRES project is discussed. A design of a drilling tool equipped with the proposed technology is presented. The solution in question makes it possible to increase the efficiency of the drilling process, which is confirmed by computer simulations. Also, introductory tests of a drilling process supported by torsional vibration generated by an electromagnetic torque generator provided in the KOMAG laboratory facility show the reduction of the drilling time by almost two-fold. In our opinion, adding torsional vibration acting on the plane of a drilled wall that equals natural frequencies of the drilled material represents a promising new technology for drilling. The presented work constitutes the basis for the development of the proposed technology and allows us to conclude that the developed method will be of great interest to manufacturers of drilling machines and devices.

One Phase Well OPW : Unlock Shallow Reservoir Efficient and Economically by Eliminating Surface Casing

Tunu is a mature giant gas and condensate field locate in Mahakam Delta, East Kalimantan, Indonesia. The field has been in development for almost 30 years and currently has been considered as a mature field where to put a state of an economic well has become more challenging nowadays. The deeper zone of Tunu has no longer been considered as profitable to be produced and the current focus is more on the widespread shallow gas pocket located in the much shallower zone of Tunu. One phase well is architecture without 9-5/8" surface casing. OPW is one-section drilling using a diverter mode from surface to TD without using BOP. Historical for OPW is began from 2018, where drilling reservoir section using diverter mode in two-phase. In 2018 also succeeded in performing perforated surface casing. Due successfully in drilling operation using diverter and perforated surface casing, in 2019 drilling trials for OPW were carried out. Until now, the OPW architecture has become one of the common architecture used in drilling operations as an optimization effort. Until December 2020 PHM has completed 15+ OPW wells. A general comparison of OPW and SLA well is at the cost of constructing a well of approximately 200,000 - 300,000 US$. The disadvantages of OPW wells are more expensive in the mud and cement section when using a 9-1/2" hole, but in terms of the duration, OPW drilling time is more efficient up to 2-3 days. If viewed from the integrity of the OPW wells, from 15 OPW wells that have been completed, only 2 of them have SCP.

Deployment of Downhole Mechanics Measurement System and Drilling Dynamics Modelling to Enhance Overall Drilling Performance Under Complete Mud Losses Environment

Drilling surface 16-in. and 12.25-in. sections in Middle East often accomplished by complete mud losses where downhole dynamic changed completely. To increase the performance and reduce drilling time the Positive Displace Motors (PDM) are used, however drilling under complete mud losses scenario may lead to a failure of the PDM, Measure While Drilling (MWD) tool, jar and any other components of the Bottom Hole Assembly (BHA). This manuscript describes the study of BHA dynamic in total loss scenario aiming to increase Rate of penetration (ROP) and decrease mechanical failures. The changing in drilling dynamics under complete mud losses increases the severity of shock and vibrations (S&V), BHA whirl and, consequently, leads to downhole failures. Local practices have been used to control this risk by taking an over conservative approach, limiting Weight on Bit (WOB) and Revolution per Minute (RPM) to very low levels, affecting overall performance. To comprehensively understand the level of shock and vibrations under complete mud losses based on the modeled data, a Downhole Mechanics Measurement (DMM) system was used in the BHA to acquire the required data in real time to confirm and further improve the modeling of drilling dynamics. A drilling schedule with several combinations of WOB and RPM was developed to cover the full drilling envelop. This study provided valuable understanding on the drilling dynamics while drilling under complete mud losses and allowed to clearly define the limiting boundaries to optimize ROP without jeopardizing the mechanical integrity of the BHA, particularly the PDM and drilling jar. On each formation drilled, RPM, WOB were changed to cover all possible combinations and, using the continuous real time measurement, ROP was optimized based on the level of shocks and vibrations experienced. Furthermore, the recorded mode Low and High-frequency data enabled to model the drilling dynamics and to quantify the effects of shocks and vibrations on the BHA. As a result, the wells have been drilled with significant ROP improvement (saving one day per run) and without downhole failures, achieving higher than expected performance results.

Accuracy and Wear Evaluation of the Customized Zirconia Guided Sleeves

This in vitro study investigated the accuracy and wear conditions of three drill sleeve distances (0.01, 0.02, and 0.03 mm) for 3D-guided stents in simulated clinical dental implant surgery. Fifteen sets of upper and lower partially edentulous epoxy tooling board models with four edentulous first molar sites were prepared in a Nissin Simple Manikin II and set on a dental chair. Sixty computer-aided design and computer-aided manufacturing (CAD/CAM) designed and guided stents with three drill sleeve distances were prepared in this study. The maximum height (Sz) of the wear roughness of drills, maximum deviation, and drilling time were observed. The highest maximum horizontal deviations were observed at the upper first molar (0.48 ± 0.12 mm, p < 0.001). The highest maximum vertical and angular deviations were observed at the lower left first molar (1.08 ± 0.35 mm and 5.61° ± 1.21°, respectively, p < 0.001). Only angular deviation significantly differed among the three drill sleeve distances (p = 0.046); the 0.03 mm distance exhibited the maximum angular deviation (3.92° ± 1.87°). The bigger drill sleeve distance (0.03 mm) was associated with more wear roughness (8.70 ± 2.29 µm) of the drills. Guided stents with varying drill-sleeve distances (0.01, 0.02, and 0.03 mm) exhibited no significant difference in preparation drilling time and abrasive wear. In practice, the optimal drill sleeve distance for single-type CAD/CAM-guided stents of dental implantation was 0.01 mm.

A 20 Years Systemic Study of Drilling Practices in a Geothermal Venture Reveals Insightful Findings

Geothermal drilling has increased in the recent years with the renewable energy initiatives. Geothermal plants provide more than 6% of California's electricity. A large sum from the development budget is consumed by the drilling. This paper systematically analyzes and reviews the drilling activities and operations in a geothermal venture in Hawaii for more than 20 years to enhance the drilling operations and save costs. The paper starts by studying the geology of the area, which is located in an active volcanic region. Then, an extensive data collection was performed that went back to more than 20 years. The data was preprocessed and cleaned to be used in the analysis. The well designs were analyzed and the distribution of the drilling time was determined. After that, the performance of the geothermal drilling was benchmarked with the oil and gas drilling and the geothermal drilling in different parts around the world. The geology of the area is challenging with basaltic formation and tectonic movements. Volcanic eruptions that leads to closing wells were encountered in the recent years. As for the drilling, six challenges were identified and deeply analyzed. These challenges include: lost circulation, stuck pipe, cementing, low rate of penetration (ROP), logistics issues, and safety concerns. Each of these challenges was intensely investigated and solutions were proposed. The benchmarking with the oil and gas industry and other geothermal drilling operations shows that the geothermal drilling operations can be enhanced significantly. This improvement in the drilling in the geothermal venture will result in huge cost savings. A set of recommendations to improve the performance is presented as new organizational and workflow changes, analysis and elimination of nonproductive time (NPT), and novel engineering redesigns.

Systematic Build-Up Pressure Analysis Advances Accurate Fingerprinting of Formation Breathing in Gas Wells

Differentiating wellbore breathing from real influxes in Alberta's Deep Basin has been problematic in the past as they both result in similar surface parameters. An incorrect interpretation of formation breathing may lead to significant non-productive time (NPT) as secondary well control operations from an influx can take days. On the contrary, a false negative will force drillers to perform secondary well control procedures that may lead to loss of circulation if excessive and unnecessary pressure is exerted on the formation. MPD allows for a systematic approach to identify wellbore breathing more accurately in gas wells. The process involves a series of consecutive pressure build-up and flowback tests with close real-time monitoring to identify a breathing formation that is returning fluid to surface as microfractures close. This paper describes the protocol designed for distinguishing wellbore breathing and illustrates how several drilling parameter trends were interpreted to correctly identify wellbore breathing characteristics and differentiate them from a migrating gas influx. Testing the procedure on multiple wells resulted in 70% operational time savings from reduction in post mud rollover delays on breathing wellbores. This paper shows that the methodology utilized provides consistent and effective results using the MPD techniques, eliminates the ambiguity of wellbore breathing versus actual influxes, and shows the potential application in more areas that are prone to this problem, reducing uncertainty, NPT, and total drilling time.

One Phase Well (OPW): Unlock Shallow Reservoir Efficiently and Economically ay Eliminating Surface Casing

Tunu is a mature giant gas and condensate field locates in Mahakam Delta, East Kalimantan, Indonesia. The area has been developed for almost 30 years and is currently considered a mature field, where putting a state of an economical oil well has become more challenging nowadays. The deeper zone of Tunu has no longer been considered profitable to be produced. The current focus is more on the widespread shallow gas pocket located in the much more external area of Tunu. One phase well is architecture without 9-5/8" surface casing. OPW is one-section drilling using a diverter mode from surface to TD without using BOP. Historical for OPW is began from 2018, where drilling reservoir section using diverter mode in two-phase. In 2018 also succeeded in performing perforated surface casing. Due to a successful drilling operation using diverter and perforated surface casing in 2019, drilling trials for OPW were carried out. The OPW architecture has become one of the standard architectures used in drilling operations as an optimization effort. Until December 2020, PHM* has completed 15+ OPW wells. A general comparison of OPW and SLA well is at the cost of constructing a well of approximately 200,000 - 300,000 US$. The disadvantages of OPW wells are more expensive in the mud and cement section when using a 9-1/2" hole. But, OPW drilling time is more efficient in terms of the duration, up to 2-3 days. Based on the integrity of the OPW wells, from 15 OPW wells that have been completed, only 2 have SCP.

A STUDY OF DRILL INDUCED HEARING LOSS IN THE CONTRALATERAL EAR FOLLOWING MASTOID SURGERY.

Background: Mastoidectomy is the mainstay of COM treatment . Usage of the micro motor drill has an effect on the contralateral ear due to the noise induced by the drill and the sound-conducting characteristic of the intact skull. Aims And Objectives: 1. To identify the drill induced hearing loss in the contralateral ear, by transient evoked otoacoustic emissions following mastoidectomy. 2. To identify the relation between the type of burr tip used and the amount of hearing loss. Methodology: This study consisted of 63 patients that underwent mastoidectomy. A pre-operative PTA and TEOAE was done. PTA was repeated on POD-1 and POD-7. TEOAE was done on POD-1,3 and 7. Intraoperatively, the type of burr tip used and the individual drilling time for each type of drill bit was recorded. Results: 37 patients developed transient SNHL by POD-3. All patients recovered by POD-30. Higher frequencies of 3000 Hz and 4000 Hz were commonly affected. No change was detected on PTA. Conclusion: The drill is not only a source of noise but is also a strong vibration generator. These strong oscillations are transmitted into the cochlea. Thus surgeons should select appropriate burrs and drills to minimize the temporal bone vibrations.

Driving Superior Performance in Brazilian Pre-Salt - The Challenges, Solutions and Achievements of Shell and Providers in Exploratory Pre-Salt Wells in Brazil

The Brazilian Pre-Salt has gained importance as an essential world-class province given its prolific production and thanks to its many challenges, it has incentivized the market to look for better ways to faces these technical challenges safely. This article aims to describe the main challenges faced by Shell and Constellation as well as the approach adopted to improve the operations’ safety and reduce drilling time, significantly reducing the drilling costs in an exploratory campaign in the Brazilian Pre-Salt. The campaign was based on the buildup of a partnership between the drilling contractor, operator and the main services provider, Halliburton, creating a transparent and collaborative environment, which improved all parties’ ownership and accountability. The application of many processes and techniques such as Step Seven, Stop Work Authority and Design of Work improved safety and efficiency. A precise equipment selection, detailed planning and careful execution with disciplined application of a learning mindset were also paramount to drilling performance. Four pre-salt wells were drilled in the campaign at Sul de Gato de Mato (2 wells), Alto de Cabo Frio and Saturno prospects with all of them qualifying in terms of drilling time as best in class (BIC), i.e., within the top 5% percentile. In 2019, the GdM3 well was the fastest delivery of a pre-salt well out of the 250+ wells in the region. The well GdM4 drilled in 2020 as part of the same campaign broke the previous record by seven days, being the fastest pre-salt well ever drilled with its 18 dry hole days mark. The main reason associated with the campaign´s success was the utilization of the DID-PDCA methodology, which promoted the integration of all the workforce in a cycle towards continuous improvement by: (i) carefully selecting the equipment and experienced service providers, (ii) generating detailed plans of the drilling activity and engaging all those involved in the delivery, (iii) establishing and applying a HSE strategy for safety culture enhanced and (iv) constantly monitoring of performance and discussing the next steps. Along this article a summary of well layout, the drilling phase duration, some of the key performance improvement initiatives as well as how they were generated will be shared.