scholarly journals Development of a Weighted Barite-Free Formate Drilling Mud for Well Construction under Complicated Conditions

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4457
Author(s):  
Valentin Morenov ◽  
Ekaterina Leusheva ◽  
Tianle Liu

Construction of oil and gas wells at offshore fields often involves high formation pressure and the presence of swellable clay rocks in the section. In addition, productivity preservation is also an important aspect. For this purpose, it is necessary to reduce the solids content of the drilling mud. The purpose of this work is to develop, improve, and study compositions of weighted drilling muds with low content of solids, on the basis of organic salts of alkali metals and polymers for the construction of wells prone to rock swelling and/or cavings, as well as drilling fluids for drilling-in the formation. In order to achieve the set goal the following is required: Analysis of existing drilling muds of higher density for drilling wells in unstable rock intervals and for drilling in the productive formation; analysis of experience in using drilling systems on the formic acid salts base and substantiation of requirements for flushing fluids during well construction; development and investigation of drilling mud compositions on the formate base; and the evaluation of inhibiting effect of systems containing organic salts, polymer reagents, and calcium carbonate on clay samples. The developed drilling mud is characterized by a high inhibiting ability that allows minimized mud-weighting by the natural solid phase. This reduces the volume of prepared mud and facilitates the regulation of its properties by reducing the dispersion of drilled cuttings; it eliminates problems related to hydration and the swelling of active clay rocks; and stabilizes unstable argillites prone to caving. The low solids content, low filtration rates, and inhibitory nature of the mud allows high stability of the rheological properties of the mud, and preserves oil and gas reservoir productivity under conditions of elevated formation pressure.

2018 ◽  
Vol 71 ◽  
pp. 00013
Author(s):  
Sławomir Wysocki ◽  
Magdalena Gaczoł ◽  
Marta Wysocka

While drilling through clay rocks using water-based mud, number of challenges need to be faced in view of hydration and swelling of this type of rock. Those phenomena consist in the fact, that clay mineral grows in volume due to water contact. In order to limit hydration phenomenon, for clay rocks drilling are used drilling muds with addition of chemical agents called hydration inhibitors. The article describes studies, which resulted in development of new formula of drilling mud with addition of a new short-chained amino polymer developed in Drilling, Oil and Gas Faculty AGH-UST Krakow. For the developed mud, tests of technological parameters were conducted according to API RP 13B-1 as well as specialist examinations: linear swelling of Miocene shale and clay rock disintegration. Studies also consists of syntheses of polyampholyte and short-chained cationic polymer. Based on performed studies, it was found that studied mud is characterized by good and easy to regulate technological parameters as well as effective inhibition of hydration, swelling and disintegration of clay rocks.


Author(s):  
Winarto S. ◽  
Sugiatmo Kasmungin

<em>In the process of drilling for oil and gas wells the use of appropriate drilling mud can reduce the negative impacts during ongoing drilling and post-drilling operations (production). In general, one of the drilling muds that are often used is conventional mud type with weighting agent barite, but the use of this type of mud often results in skin that is difficult to clean. Therefore in this laboratory research an experiment was carried out using a CaCO3 weigting agent called Mud DS-01. CaCO3 is widely used as a material for Lost Circulation Material so that it is expected that using CaCO3 mud will have little effect on formation damage or at least easily cleaned by acidizing. The aim of this research is to obtain a formula of mud with CaCO3 which at least gives formation damage. Laboratory experiments on this drilling mud using several mud samples adjusted to the property specifications of the mud program. Mud sample consists of 4, namely using super fine, fine, medium, and conventional CaCO3. First measuring mud properties in each sample then testing the filter cake breaker, testing the initial flow rate using 200 ml of distilled water and a 20 micron filter disk inserted in a 500 ml HPHT cell then assembled in a PPA jacket and injecting a pressure of 100 psi. The acidification test was then performed using 15% HCL and then pressured 100 psi for 3 hours to let the acid work to remove the cake attached to the filter disk (acidizing). Laboratory studies are expected which of these samples will minimize the formation damage caused by drilling fluids.</em>


Fluids ◽  
2021 ◽  
Vol 6 (9) ◽  
pp. 327
Author(s):  
Ekaterina Leusheva ◽  
Nataliia Brovkina ◽  
Valentin Morenov

Drilling fluids play an important role in the construction of oil and gas wells. Furthermore, drilling of oil and gas wells at offshore fields is an even more complex task that requires application of specialized drilling muds, which are non-Newtonian and complex fluids. With regard to fluid properties, it is necessary to manage the equivalent circulation density because its high values can lead to fracture in the formation, loss of circulation and wellbore instability. Thus, rheology of the used drilling mud has a significant impact on the equivalent circulation density. The aim of the present research is to develop compositions of drilling muds with a low solids load based on salts of formate acid and improve their rheological parameters for wells with a narrow drilling fluid density range. Partially hydrolyzed polyacrylamide of different molecular weights was proposed as a replacement for hydrolized polyacrylamide. The experiment was conducted on a Fann rotary viscometer. The article presents experimentally obtained data of indicators such as plastic viscosity, yield point, nonlinearity index and consistency coefficient. Experimental data were analyzed by the method of approximation. Analysis is performed in order to determine the most suitable rheological model, which describes the investigated fluids’ flow with the least error.


2021 ◽  
Author(s):  
Raymond Saragi ◽  
Mohammad Husien ◽  
Dalia Salim Abdullah ◽  
Ryan McLaughlin ◽  
Ian Patey ◽  
...  

Abstract A study was carried out to examine formation damage mechanisms caused by drilling fluids in tight reservoirs in several onshore oil fields in Abu Dhabi. Three phases of compatibility corefloods were carried out to identify potential to improve hydrocarbon recovery and examine reformulated/alternate drilling muds and treatment fluids. Interpretation was aided by novel Nano-CT quantifications and visualisations. The first phase examined the current drilling muds and showed inconsistent filtrate loss control alongside high levels of permeability alteration. These alterations were caused by retention of drilling mud constituents in the near-wellbore and incomplete clean-up of drilling mud-cakes. Based upon these results, reformulated and alternate drilling muds were examined in Phase 2, and there was a positive impact upon both filtrate loss and permeability, although the Nano-CT quantifications and visualisations showed that drilling mud constituents were still having an impact upon permeability. Candidate treatment fluids were examined in Phase 3, with all having a positive impact and the best performance coming from 15% HCl and an enzyme-based treatment. The interpretative tools showed that these treatments had removed drilling mud-cakes, created wormholes, and bypassed the areas where constituents were retained. The compatibility corefloods on tight reservoir core, alongside high-resolution quantifications and visualisations, therefore identified damaging mechanisms, helped identify potential to improve hydrocarbon recovery, and identify treatment fluid options which could be used in the fields.


Author(s):  
Bunyami Shafie ◽  
Lee Huei Hong ◽  
Phene Neoh Pei Nee ◽  
Fatin Hana Naning ◽  
Tze Jin Wong ◽  
...  

Drilling mud is a dense, viscous fluid mixture used in oil and gas drilling operations to bring rock cuttings to the earth's surface from the boreholes as well as to lubricate and cool the drill bit. Water-based mud is commonly used due to its relatively inexpensive and easy to dispose of. However, several components and additives in the muds become increasingly cautious and restricted. Starch was introduced as a safe and biodegradable additive into the water-based drilling fluid, in line with an environmental health concern. In this study, the suitability of four local rice flours and their heat moistures derivatives to be incorporated in the formulation of water-based drilling fluid was investigated. They were selected due to their natural amylose contents (waxy, low, intermediate, and high). They were also heat moisture treated to increase their amylose contents. Results showed that the addition of the rice flours into water-based mud significantly reduced the density, viscosity, and filtrate volume. However, the gel strength of the mud was increased. The rice flours, either native or heat moisture treated, could serve as additives to provide a variety of low cost and environmentally friendly drilling fluids to be incorporated and fitted into different drilling activity.


2018 ◽  
Vol 7 (1) ◽  
pp. 100
Author(s):  
Foster Gomado ◽  
Forson Kobina ◽  
Augustus Owusu Boadi ◽  
Yussif Moro Awelisah

The superb rheological features of bentonites makes them an excellent candidate in drilling operations. Its capacity of bentonite to swell and extend to a few times its unique volume gives it the gelling and viscosity controlling quality. The execution of clay or specifical bentonite as a great consistency controlling operator in drilling fluids largely depends on the great extent of its rheological conduct. Ghana as of late found oil and it has tossed a test to research to explore the utilization of local materials in the oil and gas operations. A rheological study was conducted on local clay samples from Ajumako, Saltpond and Winneba in the Central district of Ghana as a viscosifier in drilling muds. This will help to improve the local content of Ghana's oil and gas industry. Drilling muds were prepared from the samples in addition to a control mud using imported non-treated bentonite. The local clay samples were subjected rheological test where the flow behavior of the muds was determined by measuring the gel strength, plastic viscosity, and the yield point. The experimental values were compared to the API standards. It was revealed that the local clay had some potential features of bentonite and could be utilized as controlling operators in drilling fluids provided the clays are beneficiated to enhance their rheological properties. This novel tend to improve the local content in oil and gas industry in Ghana through the deployment of the local materials in oil and gas operations in the nation.


Nafta-Gaz ◽  
2021 ◽  
Vol 77 (3) ◽  
pp. 175-186
Author(s):  
Sławomir Błaż ◽  

Invert muds are the most commonly used oil-based drilling muds. The oil to water phase ratio in invert drilling muds ranges from 65/35 up to 90/10, with the most common ones ranging from 70/30 to 80/20. At these oil to water phase ratios, the drilling mud is characterized with high stability and appropriate rheological and structural parameters allowing to adjust drilling mud density in a wide range. One of the disadvantages of invert muds is their cost (due to oil content) and environmental problems associated with waste and management of oily drill cuttings. Taking into account the properties of oil-based muds, the article presents laboratory tests aimed at developing the composition of an invert mud with a limited oil phase content and high internal phase ratio (HIPR). Drilling muds with an o/w ratio less or equal to 50/50 vary from conventional inversion muds in terms of their composition and properties. Due to the higher concentration of the dispersed inner phase, muds have reduced stability and high rheological and structural parameters. Maintaining the appropriate rheological and structural parameters of the drilling mud and its high stability is possible only through the use of appropriate chemicals adapted to the emulsion system with a specific oil to water phase ratio. In the drilling muds of this type it is also possible, due to the higher concentration of the internal phase, to partially adjust the density of the mud with the water phase, such as salt solutions, thus limiting the solids content (weighting agents) in the mud. The developed mud system should be more economical, have a reduced toxicity, while maintaining the operational advantages of invert mud. These types of muds can be used during the drilling of reactive shale formations, salt layers, gypsum and anhydrite layers, as well as for drilling productive horizons and for reconstruction works carried out in oil and gas wells.


Purpose. To substantiate the prospects for oil and gas presence in the Lower Cretaceous sediments of the Karkinit-Northern Crimean deep based on hydrogeological (hydrogeochemical, gas-hydrogeochemical and geobaric) features. Methodology. Investigations of formation waters and water-dissolved gases were based on the methods of chemical, elementary spectral and gas chromatographic analyses executed at the laboratories of subsidiary joint-stock company "Chornomornaftogaz", subsidiary "Crimean Geology" and the Institute of Geology and Geochemistry of Combustible Minerals of NASU. For the comparison of formation pressure we applied the hydrostatic coefficient (Ch). Ch is the ratio of measured formation pressure to conditionally hydrostatic at the depth of the measuring with γ=1.000 (Рf/Рch), which eliminates the influence of uneven depths of measurement and different water densities, that is, to get the reduced value. For processing materials Excell, Corell Draw and Surfer are used. Results. Regional features of formation waters in the Lower Cretaceous complex as well as their chemical composition formation conditions are established. According to retrospective data analysis on the Crimean Plains, using the information received on the Black Sea shelf, we come to a conclusion that formation waters of the Lower Cretaceous complex are mainly sedimentogenic. The sulfate-natrium (S.Na) waters of the basal horizon and the Lower Cretaceous aquiferous complex most likely are infiltrative. This is evidenced by the decrease in the indicators of metamorphism of rCa/rMg, r(Cl-Na)/rMg and the increase in Cl/Br to over 1000, the lowered content of iodine (J) and bromine (Br). Infiltrative (paleoinfiltrative) waters mixed with primary sedimentogenic waters. This was accompanied by the decrease in their mineralization and thalassogenic trace elements contents in them. Modern infiltration from the land of meteoric waters at depths of more than 2000–3000 meters through the hydrodynamic barriers of the elision water drive system is impossible, but it could be realized at the continental infiltration stages of the foreground development and before the late Cretaceous time. This is evidenced by the continuous continental conditions marked by denudation of rocks. The main processes in the chemical composition formation of formation waters of Cretaceous and Lower Cretaceous complexes could have been: leaching rocks, mixing of infiltrative fresh or saline waters with thalassogenic waters; mixing of these waters with waters of the high temperature (>2000C) dehydration of clay rocks with formation of non-infiltrative (S.Na) and (Hyd.Car.Na) waters. Based on the analysis of the hydrostatic coeficient distribution (Ch) in the basal and Lower Cretaceous aquiferous complexes the existence of the elision water pressure system within the Karkinit-Northern Crimean deep is confirmed. The cause of overhydrostatic pressures is most likely to be the dehydration of clay rocks and the intrusion of deep gases. Geobaric conditions and filtration parameters suggest that the water flows of the elision water pressure system can move from the deepest parts of the Karkinit-Northern Crimean deep towards its sides. Originality and practical significance. The nature and forming conditions of formation waters have been substantiated. According to gas-hydrogeochemical and geobaric features it was possible to distinguish localities promising for hydrocarbon prospecting in the Lower Cretaceous deposits.


2020 ◽  
pp. 44-53
Author(s):  
V. A. Parfiryev ◽  
Yu. V. Vaganov ◽  
N. N. Zakirov

The article is devoted to an analysis of the oil well construction in the fields of the Talakan group of Eastern Siberia. The low quality of the construction of oil wells is explained based on geological structure of the reservoir and the conditions of its formation, particulary, the complications encountered during drilling are given. Based on the analysis, it was found that the use of traditional monosalt and salt-saturated drilling muds is not effective enough to simultaneously solve the problems of exposing intervals of salt deposits and high-quality primary exposing of reservoirs. Based on the literature data analysis and the experience of building the first exploratory wells in Eastern Siberia, the use of hydrocarbon-based flushing liquids is justified. As a result of theoretical and laboratory studies, the compositions of invert-emulsion drilling fluids are proposed of hydrocarbons, which are available in the conditions of fields in Eastern Siberia. The results of studies for determining the effect of flushing fluids on the reservoir properties of the V10 reservoir of the Vostochno-Alinskoye oil and gas condensate field showed that recovery of core permeability after exposure to hydrocarbon-based flushing liquid was on average 90 %, which is significantly higher compared to the effect of water-based drilling muds, where the recovery coefficient is 23 %.


2018 ◽  
Vol 149 ◽  
pp. 01082
Author(s):  
Kaci Chalah ◽  
Abdelbaki Benmounah ◽  
Khaled Benyounes

Bentonite is often used in water-based drilling fluids. The xanthan gum is widely used as to increase the viscosity of the bentonite suspension. For the stabilization of the drilled layers, we use filtrate reducers: sodium carboxymethylcellulose low viscosity and cellulose polyanionic low viscosity. The objective of this work is to explain the effect of the polymers on the rheological behavior of the 5% bentonite suspensions. These results will provide practical recommendations for the rational use of different types of additives in water-based drilling muds. Our work is based on rheological trials on a viscometer. The results obtained on the bentonite 5%-xanthane suspension show a rheofluidifying behavior with yield stress conform to the Herschel-bulckly modal. While increasing the concentration of filtrate reducer decreases the yield stress and reduces the viscosity. The effect of CMC LV is more pronounced than PAC L.


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