Characteristics of oil based muds and influence on the environment (original) (raw)
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LABORATORY REPORT ON THE FACTORS THAT AFFECT THE PROPERTIES OF DRILLING MUD
This report concerns the analysis of the factors (bentonite, barite, salt contamination and sand content) that affects basic properties of drilling fluid specifically; mud weight (density), apparent viscosity and hydrogen ion concentration). The experiments were conducted at room temperature conditions (28-300C) using Mud balance, Marsh Funnel and pHydrion. The report consists of five chapters with four experiments; the first chapter is about mud properties test for water base mud using PAC additive. The results indicated that PAC materials has the effect of increasing mud viscosity. Also the increase in PAC observed to lower the mud weight of the water base mud. pH was slightly lowered with increase of PAC materials. Chapter two concerns the control of mud weight using bentonite, barite, and water back for fresh and salt water base mud. The results indicated that mud weight and viscosity of water base mud increases with increase of bentonite, barite while salt increased mud weight but decreased viscosity, and water back effect reduced both mud weight and density. Chapter three concerns drilling fluid contamination by soluble salts; Sodium chloride (NaCl), anhydrite (CaSO4), and Gypsum (CaSO4-2H2O). It was observed, that mud weight of fresh water base mud increases initially with the increase of NaCl, CaSO4 and Gypsum and later slightly decreases while the apparent viscosity decreases. Addition of Na2CO3 to Gypsum contaminated mud observed to raise the viscosity of the mud. Experiment 4 was on determination of sand content of the drilling mud using the Baroid sand content set. The results indicated that the sand content by volume percent of the drilling mud increases with the increase of the amount of sand added.
Evaluation of the Impacts of Locally Sourced Lost Circulation Materials on Drilling Muds Properties
Iconic Research and Engineering Journals, 2019
Lost circulation is one of the most troublesome and costly problems encountered in drilling. Lost circulation often results to excessive and expensive loss of muds and may lead to a blowout, stuck pipe, or formation damage. There are numerous materials which are used to prevent loss circulation. Regrettably most of the materials that are used in Nigerian Oil and Gas fields are imported. The usual argument is that locally sourced materials will adversely affect drilling mud properties. The purpose of the research was to evaluate the impacts of locally sourced loss circulation materials on drilling muds properties. Locally sourced lost circulation materials from agricultural wastes (Rice Husks, Corn Cobs and Walnut shells) were used to formulate drilling mud and the properties evaluated and compared with the drilling formulated using imported lost circulation materials. The muds formulated using lost circulation materials produced from agricultural wastes in most cases have lower viscosity and higher yield points than muds formulated using conventional / commercial lost circulation material. Therefore, they have good prospect for drilling in the sense that their low viscosity will offer less resistance to fluid flow and their higher yield points will enable them carry cuttings better. Muds formulated using Rice Husks as lost circulation materials has better gel strength. Results showed that all the mud samples have desirable mud density and mud cake thickness, but the muds formulated using Corn Cobs has lowest fluid loss value.
This report concerns the analysis of the basic techniques of formulating, testing and studying the properties of drilling fluid in contamination with different material encountered during drilling process. This report consists of six chapters with four experiments for measuring the physical properties of drilling fluid such as mud weight (density), rheology (viscosity, gel strength, yield point) sand content, wall building and filtration characteristics. The first chapter consists of introduction and theoretical principals of the experiment. The first experiment was about measurement of mud properties (viscosity density and pH). The second experiment was on mud properties test particularly control of mud weight. This is divided into two parts, Part A was about effect of adding bentonite on mud properties for fresh and salt water base mud and part B was about the effect of adding weight material (barite). It was observed that the viscosity and mud weight increases on the addition of salt to the fresh water mud. Also the addition of barite to the mud affects only mud weight but not viscosity because barite doesn’t have flocculating or deflocculating properties The third experiment was about drilling fluid contamination test. In this test we were studying the effect of contamination of monovalent chemicals (NaCl and KCl) and divalent chemicals that cause contamination are calcium sulfate (CaSO4), cement (Ca(OH)2, and Gypsum (CaSO4-2H2O). It was observed that Sodium chloride increases density of the drilling mud as well as the viscosity of mud since it is flocculant. Cement has a tendency of absorbing water from the mud and increase viscosity, but cement seems to have no any impact on mud weight. Experiment 4 was on determination of sand content of the drilling mud. This is a simple test designed to measure the level of particles in the mud of greater that 200 mesh or 75 microns. From the results obtained in this test and the general field experience shows that the sand content must not be permitted to rise above 2%, otherwise wear on pumps and tubulars will be the result. Any increase in sand content must be investigated since it is often an indication of poor solids removal efficiency.
Filtration is used in many industries to separate water from the solid. It is important to find fluid loss in drilling, cementing, fracturing, and almost every other type of downhole treatment design. The filter cake characterization is very essential for well selection of drilling fluid problems and formation damage. Therefore this study is taken up to experimentally investigate the effect of different concentrations of CMC, Starch, Wood fibers, Soda ash, Caustic soda, Bentonite and Barite on filtration loss and formation damages. Three different samples are used in this study at different concentration and a comparison is made. Although the discussion presented here is confined to fluid loss during drilling. Water-based drilling mud's including Bentonite is well-known and is being widely used in the petroleum industry. Among the important functions of water-based drilling fluid were to form filter cake on the wall of the well bore, prevent water leakage, and maintain the stability of the well wall. The properties of the water-based drilling fluid, such as the rheology and filtration loss, are affected by the fluid loss additive. Polymers, which are nontoxic, degradable, and environment friendly, are the best choice to be used as drilling fluids additives.
Journal of Petroleum Research and Studies, 2021
The most important constituents of drilling operation success is keeping the drillingfluid rheological properties within a certain limit to maintain continuity of theirfunctions in a good manner. To achieve that, the drilling mud system needs continuousand direct supervision such as measuring its rheological properties and treating anydeviation in their values. Viscosity is the most important property in hydraulic programsuccess due to its direct relation with a bottom hole cleaning during well drilling, thusrelated with the drilling rate, so this property should be kept essentially to ensurebottom hole cleaning and high drilling rate at the same time.Some chemicals should be added to the mud system to keep both viscosity and otherproperties within certain standards and the required limit ,the high cost of suchchemicals increase both the metric cost and the final cost of such wells.The aim of this research is to test the physical and chemical properties of a localmaterial, as a thin...
Formulating Drilling Mud for Troubled Zone Formation Using Locally Sourced Materials
This paper is to formulate locally drilling mud that will be used to drill trouble zones formations successfully. Trouble zones are zones with abnormal characteristics encountered during drilling operations, such as zones of high circulation lost and zones with high formation pressure. In this paper, the zone of abnormal lost circulation was considered. For drilling to be successful drilling mud was formulated and beneficiated to lessen its filtrate into the formation and also raise its density. The outcome of this research work shows that mud formulated and beneficiated with local clay and bentonite had a decrease of filtrate volume (in percentage (%)) into the formation from 22.3 to 7.8 and 5.6 to 5 respectively. The outcome of mud density after beneficiated with 70g of barite and subjecting it to temperatures up to 80°C was still very high (12.6ppg for local clay and 13.4ppg for bentonite). Since local materials used here had close results in cumulative filtrate loss and mud density, they can make use instead of foreign materials so as to save more resources that are spent on importation.
Effect of Seawater and Cement Contaminants on Drilling Water and Non-Water Based Drilling Muds
African Journal of Engineering and Environment Research Vol 5(1) 2023, 2023
Over the years, drilling for oil and gas is a high-risk and challenging venture. Despite the uncertainty and the problem associated with the drilling operations, wells are being drilled every day. To overcome these problems, the drilling mud engineers must prepare for these challenges to meet the expected revenue and the time allocated for a particular drilling job. A practical test was conducted at a temperature of 120 o F and an atmospheric pressure of 14.7 psi to determine the effects of seawater and cement slurry contaminant on drilling water and non-water-based drilling mud. The results of the sea water contaminant on water-based mud shows that there is slight increase in the plastic viscosities from 27cP to 30cP, yield point from 14 Ib/100ft 2 to 18 Ib/100ft 2 , while the results of the cement contaminant of oil-based mud of 10 grams to 50 grams show plastic viscosities increase from 24cP to 25c and yield point decrease from 12 Ib/100ft 2 to 8 Ib/100ft 2 respectively. The presence of other contaminants in the drilling mud reduces the properties as well and in turn affects the rate of penetration and its performance, and poses serious drilling problems. Based on the practical conducted and analysis of results obtained, It is recommended that a mud program should be designed to gives provision for correction of suspected or expected contaminant(s) beforehand and basic knowledge of the drilling mud chemistry must be known to effectively supervise the contaminants control and mud must be properly treated to prevent the destruction of subsurface equipment.
Effects of Solid Contents and Various Additives in Drilling Fluids
The project is done to study about the effects of solid contents and various additives in drilling fluids. The objectives of this project work were to determine the Viscosity & Density of Mud Additive (Barite BASO4 specific gravity :4.10 ~ 4.20), while STPP(sodium tri-polyphosphate Na 5 P 3 O 10) is Viscosifier.The scope of this project is limited to Water based muds only.
Lessons Learned in Drilling Pre-Salt Wells With Water Based Muds
OTC Brasil, 2013
Drilling operations in salt zones have gained importance in Brazil due to the discovery of large oil and gas reserves in the Pre-Salt area. Thus, the pursuit of excellence in such operations is requiring considerable development of new operational practices and technologies. Synthetic base mud has been the first choice to drill through evaporite sections in Pre-Salt zones. Synthetic fluids application practically eliminates salt dissolution and improves caliper quality. However, depending on the salt mobility rate, stuck bit and/or stuck pipe can happen, demanding the injection of fresh water pills for its liberation. In some wells, the frequent use of those pills resulted in enlarged sections. The situation gets worse in scenarios where loss of circulation is a major issue. On the other hand, the use of non-saturated aqueous fluids to drill soluble salts (e.g. halite, tachyhydrite and carnalite) can result in localized enlargements due to leaching process. Drilling a gauge hole is a very important issue to prevent wellbore collapse and/or problems in cementing operations. However, high operating costs associated to deep water drilling is placing additional emphasis on drilling performance in order to reduce the operational time, without losing the quality of the wells. This concern raises the issues of how to most effectively improve operational performance regarding the drilling fluid selection. The paper presents the results of the use of water based muds in the drilling of two offshore wells in Brazilian Pre-Salt area and highlights the lessons learned from the experience. Before the field application extensive lab tests and numerical simulations were carried out to support the drilling fluid design for the wells. In the first well, differences between the planned and encountered drilling conditions led to fluid replacement during the operation. On the other hand, in the second well, 2.000 m salt extension was successfully drilled to depth with no major operational problems and good drilling performance. The field application of WBM proved to be a good option to drill the salt layers in the development of Pre-Salt fields but it demands a more detailed knowledge of both lithology and stratigraphy of the evaporite section.