scholarly journals Rheological properties and damage-control mechanism of oil-based drilling fluid with different types of weighting agents

2018 ◽  
Vol 5 (7) ◽  
pp. 180358 ◽  
Author(s):  
Peng Xu ◽  
Mingbiao Xu ◽  
Zhengwu Tao ◽  
Zhihong Wang ◽  
Ting Huang

The great amount of solid particles contained in a weighting agent is a major cause of the problems in both rheology properties and damage control mechanism of an oil-based drilling fluid (OBM). Therefore, a proper type of weighting agent can be a solution for the application of OBM. In this study, three weighting agents that have been commonly used with OBM, namely, standard barite, submicron barite and superfine manganese ore, are studied. Rheological properties of OBM and the degree of formation damage are assessed with regard to the three weighting agents. The agents are also studied in aspects of particle size, micromorphology, filtration loss and wall-building property, acid dissolution efficiency of mud cake, lubricity and sedimentation stability to analyse the effects of the agents on rheological properties and the degree of damage as well as to figure out the mechanism of rheology control and damage control. For the OBM, there is a mutual effect between rheological stability and the degree of damage. In consideration of the agents' properties, we can enhance the rheological stability of the OBM and control the degree of formation damage by properly selecting particle size, using acid-soluble materials and forming the mud cake with ultra-low permeability that can easily be cleared away.

SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Yijun Wang ◽  
Yili Kang ◽  
Lijun You ◽  
Chengyuan Xu ◽  
Xiaopeng Yan ◽  
...  

Summary Severe formation damage often occurs during the drilling process, which significantly impedes the timely discovery, accurate evaluation, and efficient development of deep tight clastic gas reservoirs. The addition of formation protection additives into drilling fluid after diagnosing the damage mechanism is the most popular technique for formation damage control (FDC). However, the implementation of traditional FDC measures does not consider the multiscale damage characteristics of the reservoir. The present study aims at filling this gap by providing a complete and systematic damage control methodology based on multiscale FDC theory. First, the characteristics of multiscale seepage channels were described through petrology, petrophysics, and well-history data. Subsequently, based on laboratory formation damage evaluation experiments, the formation damage mechanism of each seepage scale was determined. Finally, based on the multiscale formation damage mechanism, a systematic multiscale FDC technology was proposed. Through the use of optimized drilling fluid based on multiscale FDC theory, high-permeability recovery ratio (PRR), high-pressure bearing capacity of plugging zone, and low cumulative filtration loss were observed by laboratory validation experiments. Shorter drilling cycle, less drill-in-fluid loss, lower skin factor, and higher production rates were obtained by using the optimized FDC drilling fluid in field application. This multiscale FDC theory shows excellent results in minimizing formation damage, maintaining original production capacity, and effectively developing gas reservoirs with multiscale pore structure characteristics.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jinliang Liu ◽  
Fengshan Zhou ◽  
Fengyi Deng ◽  
Hongxing Zhao ◽  
Zhongjin Wei ◽  
...  

Abstract Most of bentonite used in modern drilling engineering is physically and chemically modified calcium bentonite. However, with the increase of drilling depth, the bottom hole temperature may reach 180 °C, thus a large amount of calcium bentonite used in the drilling fluid will be unstable. This paper covers three kinds of calcium bentonite with poor rheological properties at high temperature, such as apparent viscosity is greater than 45 mPa·s or less than 10 mPa·s, API filtration loss is greater than 25 mL/30 min, which are diluted type, shear thickening type and low-shear type, these defects will make the rheological properties of drilling fluid worse. The difference is attributed to bentonite mineral composition, such as montmorillonite with good hydration expansion performance. By adding three kinds of heat-resistant water-soluble copolymers Na-HPAN (hydrolyzed polyacrylonitrile sodium), PAS (polycarboxylate salt) and SMP (sulfomethyl phenolic resin), the rheological properties of calcium bentonite drilling fluids can be significantly improved. For example, the addition of 0.1 wt% Na-HPAN and 0.1 wt% PAS increased the apparent viscosity of the XZJ calcium bentonite suspension from 4.5 to 19.5 mPa·s at 180 °C, and the filtration loss also decreased from 20.2 to 17.8 mL.


Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Peng Xu ◽  
Mingbiao Xu

Oil-based drilling fluids (OBDFs) have a strong wellbore stabilization effect, but little attention has been paid to the formation damage caused by oil-based drilling fluids based on traditional knowledge, which is a problem that must be solved prior to the application of oil-based drilling fluid. For ultradeep fractured tight sandstone gas reservoirs, the reservoir damage caused by oil-based drilling fluids is worthy of additional research. In this paper, the potential damage factors of oil-based drilling fluids and fractured tight sandstone formations are analyzed theoretically and experimentally. The damage mechanism of oil-based drilling fluids for fractured tight sandstone gas reservoirs is analyzed based on the characteristics of multiphase fluids in seepage channels, the physical and chemical changes of rocks, and the rheological stability of oil-based drilling fluids. Based on the damage mechanism of oil-based drilling fluids, the key problems that must be solved during the damage control of oil-based drilling fluids are analyzed, a detailed description of formation damage characteristics is made, and how to accurately and rapidly form plugging zones is addressed. This research on damage control can provide a reference for solving the damage problems caused by oil-based drilling fluids in fractured tight sandstone gas reservoirs.


Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1485 ◽  
Author(s):  
Salaheldin Elkatatny ◽  
Tural Jafarov ◽  
Abdulaziz Al-Majed ◽  
Mohamed Mahmoud

Drilling multilateral and horizontal wells through tight gas reservoirs is a very difficult task. The drilling fluid should be designed to reduce both fluid and solid invasion into the tight formation to avoid formation damage by aqueous phase trapping. The objective of this paper is to assess the effect of sodium silicate on the drilling fluid properties such as rheological and filtration properties. Rheological properties (RPs) were measured at different temperatures while the filtration test was performed at 300 °F and 300 psi differential pressure. A retained permeability calculation was determined to confirm the prevention of solid invasion. The rheological properties results confirmed that the optimal concentration of sodium silicate (SS) was 0.075 wt.% and at the same time, the temperature has no effect on the SS optimum concentration. Using 0.075 wt.% of SS reduced the filtrate volume by 53% and decreased the filter cake thickness by 65%. After mechanical removal of the filter cake, the return permeability of the tight sandstone core was 100% confirming the prevention of solid invasion. The computer tomography (CT) scanner showed that the CT number before and after the filtration test was very close (almost the same) indicating zero solid invasion and prevention of the formation damage.


2021 ◽  
Vol 58 (2) ◽  
pp. 121-126
Author(s):  
R. M. Farag ◽  
A. M. Salem ◽  
A. A. El-Midany ◽  
S. E. El-Mofty

Abstract Invasion of fluids into porous media during drilling can lead to irreparable damage and reduced well productivity. Hence, minimizing the filtration loss of the drilling fluid into the formation is very important. The stability of colloidal suspensions plays a crucial role in controlling the interfacial forces and consequently on minimizing the filtration. The zeta potential is an indicator of the stability of colloids with respect to their electrostatic interactions. In this study, the rheological properties of bentonite suspensions are investigated with and without additives. The starch and CMC were used as additives to enhance the rheological properties of bentonite. The effects of these additives on the drilling fluid filtration were examined. Zeta-potential, viscosity, gel strength and yield point were measured to characterize the extent to which control of the filtration loss of the drilling fluids can be achieved. The zeta-potential and the amount of filtration loss of water-bentonite suspensions were correlated. Finally, the results showed that the addition of either starch or carboxymethyl cellulose (CMC) enhances the filtration properties of water-bentonite suspensions.


2015 ◽  
Author(s):  
Saeed Salehi ◽  
Ali Ghalambor ◽  
Fatemeh K. Saleh ◽  
Hadi Jabbari ◽  
Stefanie Hussmann

1983 ◽  
Vol 23 (01) ◽  
pp. 11-20 ◽  
Author(s):  
Syed M. Hussaini ◽  
Jamal J. Azar

Abstract Experiments are conducted with actual drilling muds to study the behavior of drilled cuttings in a vertical annulus. The effect of parameters such as particle size, flow rate, apparent viscosity, and yield point to plastic viscosity ratio on mud-carrying capacity are studied. The applicability of a semiempirical transport model developed by Zeidler also is investigated. It has been shown that in vertical annuluses, the fluid annular velocity has a major effect on the carrying capacity of muds, while the other parameters have an effect only at low to medium fluid annular velocities. We also conclude that Zeidler's semiempirical formulations for the prediction of drilled cuttings behavior are valid with certain limitations. Introduction One of the most important functions of a drilling fluid is to transpose the drilled particles (cuttings) generated by the drill bit to the surface through the wellbore annulus. This commonly is called the "carrying capacity" of drilling mud. Factors affecting the ability of drilling muds to lift cuttings arefluid rheological properties and flow rate,particle settling velocities,particle size and size distribution, geometry, orientation, and concentration,penetration rate of drill bits,rotary speed of drillstring,fluid density.annulus inclination, anddrillpipe position in the wellbore (eccentricity) and axially varying flow geometry. With the advent of deeper drilling and better bit designs, the demand for expending most of the energy at the bit has made it necessary to minimize the pressure losses in the annulus. These pressure losses depend on the fluid velocity, fluid density, and particle concentration. By control of these factors, pressure losses can be minimized. The particle slip velocity is an important factor and is defined as the velocity at which a particle tends to settle in a fluid because of is own weight. The velocity depends on the particle size, its geometry, its specific weight, and fluid rheological properties. The carrying capacity of muds also is affected by the velocity profile in the annulus. With all these variables acting simultaneously, the determination of carrying capacity of a mud becomes a complicated problem. An optimal drilling fluid is expected to lift the cuttings from the wellbore, suspend them when circulation is stopped, and drop them at the surface. Failure to achieve this performance often leads to problems that are costly and performance often leads to problems that are costly and time-consuming to solve. To avoid such problems, the previously mentioned parameters are to be considered in previously mentioned parameters are to be considered in the design of an optimal drilling fluid. Previous Investigations Previous Investigations SPEJ P. 11


SPE Journal ◽  
2022 ◽  
pp. 1-17
Author(s):  
Emanuel Ricky ◽  
Musa Mpelwa ◽  
Chao Wang ◽  
Bahati Hamad ◽  
Xingguang Xu

Summary Drilling fluid rheology and fluid loss property are fundamental parameters that dictate the effectiveness and easiness of a drilling operation. Maintaining these parameters under high temperatures is technically challenging and has been an exciting research area for the drilling industry. Nonetheless, the use of drilling mud additives, particularly synthetic polymers, threaten ecological environments. Herein, modified corn starch (MCS) was synthesized, characterized, and investigated as an environmentally friendly rheology enhancer and filtration loss controlling agent for water-based mud (WBM) at high temperatures. The experimental results indicated that MCS exhibits better performance in improving rheological properties and fluid loss controlling ability for WBM than the commonly used mud additives. With the addition of an optimal concentration (0.3 wt%), MCS improved the rheology and fluid loss behavior of WBM formulation at harsh aging temperature (220°C) by practically 4 times and 1.7 times, respectively. The MCS was revealed to perform superbly over polyanionic cellulose (PAC) addition at all investigated temperatures. The better performance of the MCS was ascribed to the improved entanglements in the mud system owing to the additional hydroxyl (OH) groups. Besides, the Herschel-Bulkley model was found to be a constitutive model that described the rheological properties of the investigated muds satisfactorily. Moreover, the MCS was found to exhibit acceptable biodegradability properties.


2013 ◽  
Vol 748 ◽  
pp. 1273-1276 ◽  
Author(s):  
Ben Guang Guo ◽  
Li Hui Zheng ◽  
Shang Zhi Meng ◽  
Zhi Heng Zhang

The fuzzy ball drilling fluids have been developed on the basis of the circulation foam and Aphron to control lost circulation effectively. There are some difficulties in drilling U-type well, such as well-bore stability, cutting carrying problem, large torque and friction at the horizontal section, and formation damage to coal-bed. The objective of this paper was to show some applications of fuzzy ball drilling fluids on U-type wells of the Ordos Basin and prove the superiority of fuzzy ball drilling fluid in CBM drilling. To the three mentioned cases, the density of fuzzy ball drilling fluid was 0.90~1.18g/cm3, the funnel viscosity was 45~72s, the dynamic shear force was 12~19 Pa, the PV was 13~19mPa·s and the pH was ranged from 7 to 9. To use the fuzzy ball drilling fluids, the average ROP increased above 10% with no borehole complexity, such as stuck pipe, hole enlargement causing poor cleaning and etc. These cases reflected excellent properties of the fuzzy ball drilling fluids including effectively sealing, good carrying and suspension ability, formation damage control and compatible weighted by inert materials. Furthermore, the fuzzy ball drilling fluids will not affect BHA tools like motors and MWD in CBM drilling.


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