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Collaborating Authors
drilling fluid chemistry
Enzyme-based cleanup fluids are preferred for filter-cake-removal applications, especially in horizontal wells, because of several advantages compared with conventional cleanup fluids, including low reactivity, less corrosivity, more-positive environmental impact, and, ultimately, homogeneous filter-cake-removal coverage. Most enzyme-based cleanup fluids are limited to low temperatures. In the complete paper, the authors describe extensive laboratory work conducted to evaluate an enzyme-based/in-situ generated organic acid cleanup fluid for a water-based mud at a temperature of 250 F. Before describing their experimental methods, the authors provide a literature review in the complete paper detailing cleanup or removal of filter-cake damage, natural cleanup, acids and oxidizers, enzymes, enzyme-breaker systems, and factors influencing performance of enzyme breakers. The field samples were obtained from Well A. XC-polymer, starch, and PAC-L polymers were used in the drilling-fluid formulation to control fluid loss and to increase its viscosity.
Characterization and Performance Evaluation of Modified Apatite Ore as a New Acid-Soluble Weighting Agent for Drilling Fluids
Zhao, Xin (School of Petroleum Engineering, China University of Petroleum (East China) (Corresponding author)) | Zhang, Heng (School of Petroleum Engineering, China University of Petroleum (East China)) | Wang, Shuai (School of Petroleum Engineering, China University of Petroleum (East China)) | Su, Wenzhi (School of Petroleum Engineering, China University of Petroleum (East China)) | Sun, Hao (School of Petroleum Engineering, China University of Petroleum (East China)) | Ren, Xiaoxia (School of Science, Qingdao University of Technology (Corresponding author))
Summary Drilling in oil and gas reservoir formations requires the solid weighting agent used in drilling fluids to have good acid solubility to facilitate plugging removal in subsequent operations. Limestone is the most commonly used acid-soluble weighting agent, but its low density and significant thickening effect lead to a low weighting limit. To achieve control of drilling fluid density, rheology, sag stability, and acid solubility, the feasibility of using apatite (AP) ore as an acid-soluble weighting agent for drilling fluids has been discussed after it was modified by the nitrogen-containing organic polybasic phosphonic acid sodium salt. The basic characteristics of AP and modified AP (MAP) were analyzed. After that, the rheological, filtration, and sag stability properties of MAP-weighted water-based drilling fluids with densities of 1.2 g/cm and 1.6 g/cm were evaluated, and acid solubility, filter-cake permeability, core permeability damage, and plugging removal tests by acid solutions were performed to evaluate the formation protection effect. The results show that the density of AP is 2.98 g/cm, and the main component is hydroxyapatite. Its negative electricity and hydrophilicity were enhanced after surface modification, so its dispersion stability in water was enhanced, thereby improving the rheology, filtration, and sag stability properties of the MAP-weighted drilling fluid. The solubility of MAP in 10% HCl solution reached 90.13%, and the core contamination experiments show that after being soaked in HCl solution, the return permeability of contaminated cores reached higher than 90%, indicating that the MAP invading the core can be efficiently dissolved and removed in the acidic working fluids used in the subsequent completion and stimulation operations, thus effectively protecting the reservoir formation. The properties of MAP are superior to those of limestone, and it can be used as a new acid-soluble weighting agent for drilling fluids, considering both drilling fluid performance regulation and reservoir formation protection.
- North America (0.93)
- Asia > China > Shandong Province (0.28)
- Geology > Mineral (0.98)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Limestone (0.49)
Experimental Study on Permeability and Gas Production Characteristics of Montmorillonite Hydrate Sediments Considering the Effective Stress and Gas Slippage Effect
Wu, Zhaoran (School of Vehicle and Energy, Yanshan University) | Gu, Qingkai (School of Vehicle and Energy, Yanshan University) | Wang, Lei (School of Vehicle and Energy, Yanshan University) | Li, Guijing (School of Vehicle and Energy, Yanshan University) | Shi, Cheng (School of Vehicle and Energy, Yanshan University) | He, Yufa (State Key Laboratory of Natural Gas Hydrate) | Li, Qingping (State Key Laboratory of Natural Gas Hydrate) | Li, Yanghui (Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology (Corresponding author))
Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology Summary Gas permeability in hydrate reservoirs is the decisive parameter in determining the gas production efficiency and gas production of hydrate. In the South China Sea (SCS), the gas flow in tight natural gas hydrate (NGH) silty clay reservoirs is significantly affected by the gas slippage effect and the effective stress (ES) of overlying rock. To improve the effectiveness of hydrate exploitation, it is necessary to understand the influence of gas slippage in hydrate reservoirs on the permeability evolution law. For this paper, the gas permeability characteristics and methane production of hydrate montmorillonite sediments were studied at different pore pressures and ESs. Experimental data revealed that the gas permeability of montmorillonite samples before methane hydrate (MH) formation is seriously affected by the Klinkenberg effect. The gas permeability of montmorillonite sediments before hydrate formation is generally smaller than that after hydrate formation, and the gas slippage effect in the sediments after hydrate formation is weaker than that before hydrate formation. With the change in ES, the intrinsic permeability of sediment has a power law relationship with the simple ES. As pore pressure decreases and MH decomposes, montmorillonite swelling seriously affects gas permeability. However, the gas slippage effect has a good compensation effect on the permeability of montmorillonite sediments after MH decomposition under low pore pressure. The multistage depressurization-producing process of MH in montmorillonite sediments is mainly 3 MPa depressurization-producing stage and 2 MPa depressurization-producing stage. In this paper, the influence mechanism of gas slippage effect of hydrate reservoir is studied, which is conducive to improving the prediction accuracy of gas content in the process of hydrate exploitation and exploring the best pressure reduction method to increase the gas production of hydrate in the process of exploitation. Introduction As one of the most prospective clean energy sources in the 21st century, NGH mainly exists in permafrost and continental margins of the world's oceans (Sloan Jr. and Koh 2007). MH is the most important component of NGH. MHs are ice-like crystalline compounds in which the host methane molecule is surrounded by a cage of water molecules (Sloan 1998; Li et al. 2023).
- North America > United States (1.00)
- Europe > Norway > Norwegian Sea (0.64)
- Asia > China > Liaoning Province > Dalian (0.24)
- Research Report > New Finding (0.83)
- Research Report > Experimental Study (0.64)
- Asia > China > South China Sea > Yinggehai Basin (0.99)
- Asia > China > South China Sea > Qiongdongnan Basin (0.99)
- South America > Falkland Islands > South Atlantic Ocean > South Falkland Basin > Stokes Prospect > Darwin Formation (0.94)
Engineered Ultra-Low Invasion Loss Control Solution Allows Circulation, Ensuring Cement Placement and Zonal Isolation in Liner Cementing Jobs and Through Coiled Tubing – Case Studies
Fazal, Muhammad Adnan (Sprint Oil and Gas Services FZC) | Ahmad, Syed Hamza (Sprint Oil and Gas Services FZC) | Yousuf, Arif (Sprint Oil and Gas Services FZC) | Rehman, Aziz ur (Sprint Oil and Gas Services FZC) | Noor, Sameer Mustafa (Oil & Gas Development Company Limited) | Nazir, Irfan (Oil & Gas Development Company Limited)
Abstract The conventional loss cure techniques are largely reactive and include addition of coarse grade particle, fibrous material and other viscous pills that are lost into formation during loss cure attempts. Being highly invasive, these loss cure solutions block pore throats and line producing fractures causing considerable formation damage and loss of net asset value. Moreover, these techniques pose additional challenges while placing thru slim liners and coiled tubing (in rigless applications) due to elevated risk of getting the circulation ports plugged. Moreover, during the era of technological revolution and decarbonization, an effective and efficient solution aids to promote the practices producing low carbon emission. The proactive wellbore shielding loss cure is a particle size distribution-based LCM solution having excellent fluid loss properties and exhibiting low permeability barrier at the fluid-rock interface. The low permeable shielding effect offers less invasion across a broad range of pores (1microns to 4,000microns) and thereby protecting formation from any permanent impairment. The solution covers the wide range applications of loss cure throughout well life ensuring zonal isolation and saving significant rig time. Customized particle size distribution does allow LCM solution to be pumpable thru liner complying the allowable particle sizes (less than 1,000microns) and concentrations (upto 18 lbs/bbl) and for coiled tubing specialized applications with allowable particles size of 100 microns while maintaining rheological properties (Fluid Loss<50 ml/30 min, 5lbs/100ft2>Ty<10lbs/100ft2 & PV<90 cp). This paper demonstrates the working principle and practical applications of engineered solution for loss cure and successfully achieving zonal isolation in 7" liner being placed as pre-cement spacer in naturally fractured formation. The wellbore shielding pre-cement spacer ensured the cement rise above loss point thus achieving zonal isolation in partial to complete losses environment and helps in minimizing formation's impairment. The same approach was adopted to cure losses in rigless with coiled tubing in both carbonate and sandstone reservoirs for well killing and zonal isolation without plugging the CT BHA and circulation ports while complying design requirements.
- South America (0.68)
- Asia > Middle East (0.28)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Pressure Management > Well control (1.00)
- Well Drilling > Drilling Operations (1.00)
- (8 more...)
Drilling and Well Construction in Lean Clearances in Northern Region of Pakistan
Iftikhar, Ali (Mari Petroleum Company Limited, Islamabad, Pakistan) | Nasrumminallah, Muhammad (Mari Petroleum Company Limited, Islamabad, Pakistan) | Rasheed, Hassaan (Dowell Schlumberger, Islamabad, Pakistan) | Sabir, Shahid Majeed (Weatherford Oil Tools ME, Islamabad, Pakistan) | Sharif, Yasir (Weatherford Oil Tools ME, Islamabad, Pakistan)
Abstract Subject well is an exploratory well with a target depth of +/- 6000M, in one of the most challenging northern region of Pakistan. Well has multiple challenges with regards to drilling and well construction the least to mention are losses, borehole instability, intercalated formations, with steep dips along with a fault. Lean clearances in a five Casing Strings well construction were a requirement to isolate the problematic zones for safe drilling, this included running of longest 16" Liner for the first time in Pakistan, borehole enlargement of 14 3/4" to 16", later on running of 13 5/8" Flush x 13 3/8" coupled connection casing with narrow annular clearance, with customized Cementing Job to avoid surging. Running of 16" liner, drilling and construction of next section called for robust technical applications that includes drilling with aerated mud, running of 16" Liner with liner hanger for the first time in Pakistan, borehole enlargement while overcoming the various challenges as various formations (limestone, Sandstones, Clays) were drilled and later enlarged using hydraulic Under Reamer. Fit for purpose mud was used while drilling and further optimized to solid free for the smooth running of 13 5/8" × 13 3/8" Casing through lean clearance of 16" Liner. Casing running strategy has been devised to avoid Surge to formation at the same time ensuring it gets to bottom without any held up. The objectives of the section were met successfully. The paper will serve as a platform for other Operating companies in Pakistan to benefit from the lessons learnt and best drilling practices
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (0.90)
- Well Drilling > Drilling Operations > Running and setting casing (0.71)
- Well Drilling > Casing and Cementing > Casing design (0.70)
- Well Drilling > Drillstring Design > Torque and drag analysis (0.69)
Summary In the placement process of the cement slurry, treatment fluids such as the spacer are pumped ahead of the cementitious slurry to minimize the contamination of the slurry by drilling fluid and ensure superior bonding to the casing and formation. The spacer discussed in this work can harden with time and act as a settable spacer. This characteristic can be an advantage for well integrity if some spacer pockets are left in the annulus. Rheological compatibility of different mixtures of the spacer with oil-based drilling fluid (OBDF) has been studied using a rheometer, and the resulting R-factor, which indicates the degree of compatibility between fluids, has been calculated. An increase in the flow curve was observed for the mixture of the fluids. However, based on the R-index, these fluids are compatible with displacement in the wellbore. A nonionic surfactant, typically used in conventional spacers acting as an emulsifier and a water-wetting agent, was used in the hardening spacer design. The results show that the addition of OBDF to hardening spacer containing surfactant can increase viscoelasticity. Hardening spacer containing surfactant can successfully reverse the OBDF emulsion. By performing a small-scale mud displacement experiment, we observed that surfactant can improve the wall cleaning efficiency of the spacer while having minimal impact on the bulk displacement.
- Europe (1.00)
- North America > United States > California (0.28)
- Research Report > New Finding (0.48)
- Research Report > Experimental Study (0.48)
Pipe Viscometer for Continuous Viscosity and Density Measurement of Oil Well Barrier Materials
Lima, V. N. (NORCE Norwegian Research Centre AS) | Randeberg, E. (Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio)) | Taheri, A. (NORCE Norwegian Research Centre AS (Corresponding author)) | Skadsem, H. J. (NORCE Norwegian Research Centre AS)
University of Stavanger Summary The barrier material is a crucial component for wells, as it provides mechanical support to the casing and prevents the uncontrolled flow of formation fluids, ensuring zonal isolation. One of the essential prerequisites for the success of cementing an oil and gas well is the efficient removal of in-situ fluids and their adequate replacement by the barrier material. The quality of the mud displacement is affected by both the density and the viscosity hierarchy among subsequent fluids. Consequently, accurate and reliable measurement of fluid properties can help ensure consistent large-scale mixing of cementing fluids and verification that the properties of the mixed fluid are according to plan. In this paper, we investigate the implementation of a pipe viscometer for future automated measurements of density and viscosity of materials for zonal isolation and perform a sequential validation of the viscometer that starts with small-scale batch mixing and characterization of particle-free calibration liquids, followed by conventional Class G cement and selected new barrier materials. Finally, a larger-scale validation of the pipe viscometer was performed by integrating it into a yard-scale batch mixer for inline characterization of expanding Class G oilwell cement mixing. In all cases, flow curves derived from pipe viscosity measurements were compared with offline measurements using a rheometer and a conventional oilfield viscometer. After a series of measurements and comparisons, the investigated inline measurement system proved adequate for viscosity estimation. The flow curve of the barrier materials showed results similar to measurements using a conventional viscometer, validating the proposed test configuration to continuously measure the rheological behavior of the barrier material. The pipe viscometer flow curves are generally found to be in good quantitative agreement with independent viscometer characterization of the fluids, although some of the pipe viscometer measurements likely exhibited entrance length effects. Future improvements to the pipe viscometer design involve the assessment of even longer pipe sections to allow full flow development at the highest shear rate range and possibly different pipe diameters to improve the measurement resolution of low-shear rate viscosity. Introduction The oil well cementing process involves placing cement slurries in the annular space between the casing and the rock formation. After placement, the cement hardens to form a hydraulic seal in the wellbore, preventing the migration of formation fluids into the annulus. In the placement process, the cement paste flows through the interior of the casing into the annular space that is to be cemented, displacing in-situ fluids as it is pumped toward the surface.
- North America > United States > Texas (0.93)
- Europe > Norway > Rogaland > Stavanger (0.24)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (22 more...)
PUC-Rio Summary The success of an oilwell drilling operation is directly associated with the correct formulation of drilling fluids and their rheological measurements. The goal of this study is to investigate the usage of a Fann 35A viscometer and the methodology for rheological characterization of drilling fluids by comparison with the use of a rotational rheometer. Flow curves and gel strength tests were performed considering classic measurement artifacts such as apparent wall slip, secondary flows, steady-state (SS) regime, and inertial effects, among others. In addition, a study of the relationship between pressure drop and flow rate in a tube and in an annular space was carried out to investigate the influence of the viscosity function and of the rheological properties on the design of pipelines and the correct sizing of pumps. Use of American Petroleum Institute (API) equations and curve fitting were explored as potential choices for viscosity functions. The results indicate that the use of API equation predictions can compromise the effectiveness of the drilling process, while the choice of an adequate viscosity function is essential for the correct sizing of pumps. The gel strength was evaluated in the viscometer and presented divergent results from those obtained in the rheometer. Furthermore, a grooved geometry was developed for the viscometer to avoid the effects of apparent slip at low shear rates. Some recommendations are made based on the results obtained, which lead to better accuracy in the rheological results of drilling fluids and, consequently, better performance of some functions assigned to it. The proposed improvements and methodologies proved to be promising, although in some cases the cost-benefit remained unchanged. Introduction The main functions of a drilling fluid are cleaning the hole, carrying the cuttings to the surface, and maintaining the downhole hydrostatic pressure and stability of the wellbore. To accomplish these functions, rheological properties, density, lubricity, and pH need to be measured and controlled in the field (Bourgoyne et al. 1986). However, these fluids present complex non-Newtonian behavior, so obtaining their rheological properties is not a trivial task.
Summary Understanding gas dynamics in mud is essential for planning well control operations, improving the reliability of riser gas handling procedures, and optimizing drilling techniques, such as the pressurized mud cap drilling (PMCD) method. However, gas rise behavior in mud is not fully understood due to the inability to create an experimental setup that approximates gas migration at full-scale annular conditions. As a result, there is a discrepancy between the gas migration velocities observed in the field as compared to analytical estimates. This study bridges this gap by using distributed fiber-optic sensors (DFOS) for in-situ monitoring and analysis of gas dynamics in mud at the well scale. DFOS offers a paradigm shift for monitoring applications by providing real-time measurements along the entire length of the installed fiber at high spatial and temporal resolution. Thus, it can enable in-situ monitoring of the dynamic events in the entire wellbore, which may not be fully captured using discrete gauges. This study is the first well-scale investigation of gas migration dynamics in oil-based mud with solids, using optical fiber-based distributed acoustic sensing (DAS) and distributed temperature sensing (DTS). Four multiphase flow experiments conducted in a 5,163-ft-deep wellbore with oil-based mud and nitrogen at different gas injection rates and bottomhole pressure conditions are analyzed. The presence of solids in the mud increased the background noise in the acquired DFOS measurements, thereby necessitating the development and deployment of novel time- and frequency-domain signal processing techniques to clearly visualize the gas signature and minimize the background noise. Gas rise velocities estimated independently using DAS and DTS showed good agreement with the gas velocity estimated using downhole pressure gauges.
- North America > United States > Texas (0.68)
- Europe (0.68)
- Research Report > New Finding (1.00)
- Research Report > Experimental Study (0.93)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (0.51)
- Geophysics > Seismic Surveying > Passive Seismic Surveying (0.35)
Effect of Calcium Expansive Additives on the Performance of Granite-Based Geopolymers for Zonal Isolation in Oil and Gas Wells
Gomado, Foster Dodzi (Department of Energy and Petroleum Engineering, Faculty of Science and Technology, University of Stavanger (Corresponding author)) | Khalifeh, Mahmoud (Department of Energy and Petroleum Engineering, Faculty of Science and Technology, University of Stavanger) | Saasen, Arild (Department of Energy and Petroleum Engineering, Faculty of Science and Technology, University of Stavanger) | Sanfelix, Susana G. (Department of Engineering, Faculty of Computer Science, Engineering and Economics, Østfold University College) | Kjøniksen, Anna-Lena (Department of Engineering, Faculty of Computer Science, Engineering and Economics, Østfold University College) | Aasen, Jan Aage (Department of Energy and Petroleum Engineering, Faculty of Science and Technology, University of Stavanger)
Summary Geopolymers have emerged as a promising alternative to Portland cement for oil and gas wells. Achieving effective zonal isolation by use of geopolymers may require controlling their expansion. This study investigates the effect of calcium oxide (CaO) as an expansive agent on the performance of geopolymer-based sealing materials. Specifically, we explore the impact of CaO reactivity on various material properties using isothermal calorimetry, Brunauer-Emmett-Teller (BET) surface area analysis, linear expansion (LE) test, shear bond strength, compressive strength, and hydraulic bond strength (HBS). Our results indicate that CaO reactivity is a critical factor affecting the properties and performance of geopolymers for zonal isolation. Lower reactivities are associated with longer induction periods and lower heat evolution, which in turn increase LE. While lower reactivity decreases compressive strength, it increases shear bond strength. However, the CaO with the lowest reactivity resulted in a very low HBS due to matrix cracking and leakage. Therefore, optimizing the reactivity of CaO expansive agents is essential to enhancing the properties of geopolymer-based sealing materials for oil and gas wells. Shown in this paper is the successful application of CaO as an expansive agent for granite-based geopolymers at shallow depths in oil and gas wells.
- North America > United States (1.00)
- Europe (1.00)
- North America > Canada > Alberta (0.28)
- Research Report > New Finding (0.34)
- Overview (0.34)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Drilling > Casing and Cementing > Cement formulation (chemistry, properties) (1.00)
- Health, Safety, Environment & Sustainability > Environment (0.94)
- Well Completion > Well Integrity > Zonal isolation (0.82)