Mud Balance Research Articles

Investigation on the effect of coconut husk biofiber powder on the rheological and filtration properties of water-based drilling fluid

One of the major problems encountered during drilling deeper wells is the loss of critical properties such as rheology and fluid loss control. Effective water-based muds with potential additives can improve the effectiveness of drilling operations all over the world and are very successful at resolving such issues without damaging and penetrating the formation. Many materials have been studied to prove their economic aspects for the purpose of controlling filtration loss in drilling operation. The concentration of additive is a crucial variable in assessing the efficiency and effectiveness of drilling fluid. The use of coconut husk as an additive is a novel approach and can be economically favorable for sustainable drilling. It also aids in waste management. This paper focuses on the development of drilling fluid using coconut husk as a potential additive as well as determining its rheological properties along with filtration loss using specialized laboratory equipment such Fann VG viscometer and API filtration press respectively. Mud balance was used for determination of drilling fluid density. Moreover, different particle sizes (600-425 μm, 425-300 μm, 300-150 μm and <150 μm) and concentrations (1 g, 3 g, and 5 g) of coconut husk are taken into consideration and their properties are then compared with that of conventional drilling fluid to optimize the size and concentration of the husk. The experimental results illustrated the success of coconut husk biofiber in improving the rheological and fluid loss properties of the drilling fluids. Results show that coconut husk biofiber powder can be used as effective candidate for improvement of rheological properties and controlling filtrate loss of water-based drilling muds.

LABORATORY INVESTIGATION OF IMPROVING DRILLING FLUID PERFORMANCE OF WATER BASE MUD USING OILY GRAPHITE SILICATE AND NANO SILICA PARTICLES AS ADDITIVES

Drilling performance is enhanced by the use of a mud system that prevents or retards the dispersion of formation and cuttings and minimizes torque and drag on the drill string, water base drilling fluids for adaptability with environment and ease of operation. A water base drilling fluid can have a significant role in drilling operations with its desirable properties including rheology, fluid loss, coefficient of friction (CF), PH, and fluid weight. This work studies the effect of nanoparticles and oily graphite silicate on improving the properties of water-based drilling fluid in various laboratory experiments using rotary viscometer, standard filter press, lubricity meter, Ph- meter and mud balance. In addition, fluid loss control additives were used as a control to compare the obtained results from application of nanoparticles and oily graphite and understanding the various effects of their presences in experiments. The results show a positive influence in drilling performance when compared against estimated drilling rate, which can lead to substantial savings in drilling costs, were observed. Torque values in the wells tested were generally low (between 250 and 450 Amps) drilling days were reduced by more than 20% of programmed. The compound also showed cost effectiveness in stabilizing the mud properties by eliminating the need for a defoamer. Results finding also showed that these compounds can increase yield point (YP) in mud (increased from 101b/100f12 to 121b/100ft2 ), findings also indicate that oily graphite/nanoparticles can reduce drilling fluid loss in 100psi and T = 75o f about 22% (from 4.5cc to 3.5cc during 30min). Key Words: Drilling fluid, drilling performances, nano silica particles, oily graphite silicate, water base mud, fluid loss, cost effectiveness, fluid properties and drilling parameters

Data-Driven Framework for Real-time Rheological Properties Prediction of Flat Rheology Synthetic Oil-Based Drilling Fluids.

Appropriate mud properties enhance drilling efficiency and decision quality to avoid incidents. The detailed mud properties are mainly measured in laboratories and are usually measured twice a day in the field and take a long time. This prevents real-time mud performance optimization and adversely affects proactive actions. As a result, it is critical to evaluate mud properties while drilling to capture mud flow dynamics. Unlike other mud properties, mud density (MD) and Marsh funnel viscosity (MFV) are frequently evaluated every 15-20 min in the field. The goal of this study is to predict the rheological properties of flat rheology synthetic oil-based mud (SOBM) in real time using machine learning (ML) techniques such as random forest (RF) and decision tree (DT). A proposed approach is followed to first predict the viscometer readings at 300 and 600 RPM (R 600 and R 300) and then estimate the other mud properties using the existing equations in the literature. A set of data contained MD, MFV, and viscometer readings (R 300 and R 600) for different samples from the same mud type. The mud samples were collected after going through a shale shaker. MD and MFV are measured by a mud balance and a Marsh funnel, respectively, while rheology is evaluated using a viscometer. The data were randomly split into training, testing, and validation data sets. The ML models' performance was evaluated through average absolute percentage error (AAPE) and correlation coefficient (R). The proposed models predicted the viscometer readings as a middle stage with a low AAPE that did not exceed 4.5% for both models. The suggested models forecasted the rheological properties with a good degree of accuracy, with an AAPE being less than 7% for most of the parameters. The proposed models can save costs and time since there is no need to include additional tools in the rig location. Furthermore, these models will significantly aid in avoiding serious problems and achieving better rig hydraulics and hole cleaning, which in turn will technically and economically enhance drilling operations.

The Impact of Fiscal Policy on the Current Account Balance in the Case of Bosnia and Herzegovina

This paper aims to investigate and determine the relationship between the budget, changes in GDP, price indices, and movement of the real exchange rate on one hand, and the state of the mud balance in Bosnia and Herzegovina during the period of 2005-2019. The paper covers literature related to this field, empirical knowledge, case studies of various international types of research, and certain econometric methods. The research results indicate the presence of a negative correlation between the budget deficit, reduction in prices and the real exchange rate, and improvement of the current balance. The outcomes vary depending on whether it is in the short-term or long-term horizon.

Potential of Kaolin Clay on Formulation of Water Based Drilling Mud Reinforced with Biopolymer, Surfactant, and Limestone

Drilling the wellbore into subsurface formations is the earliest stage in the life of a well that requires a suitable drilling fluid with good rheological and filtration control characteristics to achieve a successful drilling operation. This paper reports on the formulation of water-based drilling mud using kaolin clay reinforced with biopolymer, surfactant, and limestone from Tanzania. The raw materials used for the formulation were characterized using XRD, XRF, FTIR, and TGA techniques. The rheological properties, filtration loss, pH, and density of the formulated mud were measured using a viscometer, filter press, pH meter, and mud balance, respectively. The XRD results revealed kaolinite and quartz as the main minerals in all kaolin clay samples which were in agreement with the FTIR findings. The mineralogical composition of the kaolin was observed to vary with the mining sites and influenced the rheological and filtration control characteristics of the mud. The beneficiated drilling mud showed better rheological and filtration control characteristics than the commercially available bentonite mud in Dar es Salaam market and was comparable with the API standards. These results, therefore, are not only new but rather important and novel information on the potential of kaolin clay for the formulation of water based drilling mud.&#x0D; Keywords: Water-based drilling mud, kaolin clay, biopolymers, bentonite, surfactant

Variation of Temperatures with Rheological Properties of Water Based Drilling Fluid Containing Rice Husk and Other Additives

Drilling fluids rheological properties such as yield point (YP), plastic viscosity (PV), apparent viscosity (AV) and thixotropic property (Gel strength) are very important during drilling operations to prevent various drilling problems and improve the efficiency of the drilling process. Four water based drilling fluid samples containing different proportions of rice husk, xanthan gum and bentonite were investigated in this study to determine impacts of Sodium hydroxide (NaOH), Sodium chloride (NaCl), Sodium trioxocarbonate (IV) (Na2CO3) and Barite (BaSO4) on their rheological properties and pH values at temperature ranging from 30oC to 50oC. The chemical additives were added to the four samples at a given composition of 1%,2%,3% for (NaOH, NaCl, Na2CO3) and 5%, 10%, 15% for (BaSO4) by mass. The rheological properties of the samples were determined by FANN 35A viscometer using standard methods while pH meter and mud balance were used to measure their pH and density values respectively. The maximum pH, Shear- Stress, and AV corresponds to 11.6, 2.3985 Nm-2 and 112.5 cP respectively were observed in sample A with 10.5g of NaOH at 50oC while the highest YP value of 170 lbf/100ft2 was also observed at 35oC. However, maximum gel strength, GS (10 sec) and 10(min) were observed in the sample A with 190 lbf/100ft2 and 190 lbf/100ft2 for 10.5g of NaOH and 189 lbf/100ft2 and 191 lbf/100ft2 for 52.5g of BaSO4 respectively at temperature of 50oC. Furthermore, the same sample gave the lowest value of mud weight when the sample contain 3.5g of each additive (NaOH, NaCl and Na2CO3) at 35oC corresponds to 8.98 lb/gal. Drilling fluids produced with bentonite, rice husk, xanthan gum with appropriate proportion of NaOH and BaSO4 could be effective water based drilling fluid that can serve effectively in drilling operations at reasonable high temperature.

Eco-Friendly Bridging Material: Experimental Characterization of Eggshells as an Affordable Natural Waste Non-Damaging Lost Circulation Material to Reduce Drilling Fluid Cost in Reservoir Drill-In-Fluid System

Lost circulation nowadays became one of the major problems in many drilling operations worldwide. This problem is complicated for it can significantly cause non-productive time during drilling operations. This research aims to study eggshells as a LCM and to provide further insight about the reliability and cost analysis of eggshells as a potential drilling fluid additive. Moreover, the research successfully identified the usage of an abundant natural waste, i.e. eggshells, as an environmentally friendly fluid additive. This research also investigated the technical feasibility of the eggshells and also its economics impact on drilling operations. In addition, it is found that the eggshells can also act as a non-damaging LCM for production zone that is more affordable as compared to other natural waste loss circulation materials and current commercially chemical. Series of laboratory tests were conducted such as mud balance for the density test, rheological test using viscometer Fann Vg, filtration loss test with filter press, and also alkalinity (pH) test. An excellent result from filtration loss test i.e. decreased fluid losses and showed great improvement almost same as commercially CaCO3 result in the filter cake thickness. The research proves great potential of the utilization of eggshells as a multi-purpose additive in a drilling fluid. Economic analysis also suggests that it can possibly be implemented and to be further developed for a large-scale field operations. Finally, it is found that using eggshells as LCM can reduce the cost up to 72.2 % cheaper than commercial CaCO3. It is also safe for drilling in the production zone (pay-zone) because of its solubility on acid that it can disappear during the acidizing job. If this paper can be implemented on a wide-range scale it will be very beneficial to reduce other commercial additives usage without losing its reliability.

Automatic Measurement of the Dependence on Pressure and Temperature of the Mass Density of Drilling Fluids

Summary Drilling fluids are subject to substantial variations in pressure and temperature while they are circulated in a well. These changes are so great that the mass density of the drilling fluid varies significantly during circulation. Accurate estimation of the hydrostatic and hydrodynamic pressures therefore requires a reliable model of the pressure and temperature dependence of the mass density of the drilling fluid. Usually, the mass density of a drilling fluid is measured manually with a mud balance. The pressure and temperature dependence of the mass density of the fluid [i.e., its pressure, volume, and temperature (PVT) behavior] is then calculated from a PVT model of its components and their relative proportions. However, variations in the composition of the fluid mix and uncertainties in the PVT behavior of each component may lead to inaccuracies. To overcome these limitations, an apparatus has been designed to measure the PVT behavior of the drilling fluid directly and automatically. The setup measures both the mass density and the speed of sound of the fluid at specific conditions of pressure and temperature. It is possible to estimate the adiabatic compressibility from the speed of sound in the liquid mix. The device utilizes a heat exchanger from which the specific heat capacity of the drilling fluid can be derived. The isothermal compressibility can be calculated by combining the specific heat capacity and the adiabatic compressibility. While estimating the specific heat capacity using the heat exchanger, the thermal conductivity of the fluid is also estimated as a byproduct. A PVT model of the drilling fluid is obtained by combining measurements made at different conditions of pressure and temperature. The automatic and continuous provision of drilling fluid PVT behavior enhances the precision of model predictive drilling control systems and, at the same time, can simplify their configuration, therefore making them more accessible to any drilling operation.

Development of New Models to Determine the Rheological Parameters of Water-Based Drilling Fluid using Artificial Neural Networks

It is well known that drilling fluid is a key parameter for optimizing drilling operations, cleaning the hole, and managing the rig hydraulics and margins of surge and swab pressures. Although the experimental works represent valid and reliable results, they are expensive and time consuming. In contrast, continuous and regular determination of the rheological fluid properties can perform its essential functions during good construction. The aim of this study is to develop empirical models to estimate the drilling mud rheological properties of water-based fluids with less need for lab measurements. This study provides two predictive techniques, multiple regression analysis and artificial neural networks, to determine the rheological properties of water-based drilling fluid using other simple measurable properties. While mud density, marsh funnel, and solid% are key input parameters in this study, the output models are plastic viscosity, yield point, apparent viscosity and gel strength. The prediction methods have been applied on datasets taken from the final reports of two wells drilled in the Ahdeb oil field, eastern Iraq. To test the performance ability of the developed models, two error-based metrics (determination coefficient R2 and root mean square error have been used in this study. The current results support the evidence that MW, MF, and solid% are consistent indexes for the prediction of rheological mud properties. Both mud density and solid content have a relative-significant effect on increasing PV, YP, AV, and gel strength. The results also reveal that both MRA and ANN are conservative in estimating the fluid rheological properties, but ANN is more precise than MRA. Eight empirical mathematical models with high performance capacity have been developed in this study to determine the rheological fluid properties using simple and quick equipment such as mud balance and marsh funnel. This study presents cost-effective models to determine the rheological fluid properties for future well planning in Iraqi oil fields.

Production of water-based mud for drilling operation application

A successful drilling operation is heavily dependent on the effectiveness of the drilling fluid's design in use. This study attempts to evaluate the rheological and filtration properties of water-based drilling mud (WBDM) upon the addition of Stearyl Acrylate-Behenyl Acrylate (SABA) copolymer, silicon dioxide (SiO2), and nickel (III) oxide (Ni2O3) nanoparticles. This SABA copolymer-nanofluid was prepared by dissolving the nanofluid in a SABA polymer solution and homogenizing it using ultrasonication. The properties were studied using mud balance, viscometer, and low-pressure low-temperature (LPLT) filter press. The rheological and filtration properties of SABA copolymer were found to imply that it could improve drilling fluid performance. However, the addition of nanoparticles gave a better performance of rheological and filtration properties on WBDM. SABA copolymer with 5000 ppm concentration shows the best performance due to showing the highest viscosity compared to basic drilling fluid. Also, the addition of 800 ppm of Ni2O3 concentration into 5000 ppm of SABA shows the lowest fluid losses. The experimental results indicate that SABA copolymer shows a great potential application and the addition of nanoparticles shows that nanotechnology has a lot of potentials to improve WBM performance

Inline Setup Provides Automatic Measurement of PVT Behavior of Drilling Fluids

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 204084, “Automatic Measurement of the Dependence on Pressure and Temperature of the Mass Density of Drilling Fluids,” by Eric Cayeux, SPE, NORCE, prepared for the 2021 SPE/IADC International Drilling Conference and Exhibition, originally scheduled to be held in Stavanger, 9–11 March. The paper has not been peer reviewed. The mass density of drilling fluids usually is measured manually with a mud balance. The pressure and temperature dependence of the mass density of the fluid [i.e. its pressure/volume/temperature (PVT) behavior] then is estimated. Variations in the composition of the fluid mix and uncertainties regarding the PVT behavior of each component, however, may lead to inaccuracies. An apparatus that measures the PVT behavior of the drilling fluid contained in a pit directly and automatically has been designed. Inline PVT Measurement The pressure and temperature dependence of drilling fluids can be described by a biquadratic function. However, API Recommended Practice 13D recommends using a linear function of temperature combined with a quadratic form of pressure. Because this process involves six parameters, at least six measurements must be made under different conditions of pressure and temperature. A starting point is to measure the mass density of the fluid under six different pairs of pressures and temperatures. To keep the design of the apparatus as simple as possible, it ideally would not operate under high-pressure and -temperature conditions. Therefore, knowing the range of pressures and temperatures sufficient for taking sample measurements is useful in order to be able to extrapolate the model at higher pressure and temperature conditions with acceptable accuracy. The densitometer’s measurement precision of 0.05 kg/m3 and repeatability of 0.01 kg/m3 is known, so stochastic simulations of the possible measurement error for various spans of investigated pressures and temperatures can be performed. In this study, the authors con-sider that the calibrated PVT model shall be used for a range of pressure of 1000 bar and a range of temperature of 200°C. It is possible to calculate the root mean square of the proportion error between the predicted density value and the “true” value when varying stochastically the systematic bias on the density measurement when the calibration samples are spanning small ranges of pressure and temperature. A possible design for an inline apparatus could be to pump the drilling fluid past a controllable heating element and having a controllable choke downstream of the densitometer apply a pressure while measuring the mass density. The setpoints for the heating element and the choke would be changed six times in order to collect the necessary mass densities to calibrate the PVT model. Changing the temperature of the heating element, however, can require several minutes, and gathering a complete set of calibration measurements may easily take 15 to 30 minutes. An alternative could be to perform six measurements simultaneously. The densitometers can be mounted in series. The configuration could be with six parallel branches or any combinations between series and parallel branches. With two parallel branches, in one branch the temperature of the fluid is not modified, while it is modified in the second branch. For each of the two branches, back pressure is applied at two intermediate positions. This configuration has the advantage of using fewer chokes and pressure sensors (four instead of five).

Development of water based drilling fluid using tamarind seed powder

While drilling a well, drilling fluids incurs 15–18 per cent of the overall cost. While preparing a drilling fluid, there are three fundamental considerations. It should be simple to use, not too expensive, and it should be environmentally sustainable. The formulation of a mud system begins with the selection of a mud family that, according to the rock formations and drilling fluid properties, will be sufficient for drilling a well. In order to develop a drilling fluid, we experimented and used tamarind seed powder with bentonite and barite. With approximately 8 to 10 seeds in each pod, tamarind seeds contained in kernels or pods are around 3 to 6 in. long. The average weight of pod is around 0.064 g. In general, a complete growntamarind tree produces around 175 to 250 kg of seed/kernel. The density of different samples with a mixture of bentonite, barite and tamarind seed powder ranging from 5 to 20 g was found using mud balance. Results show that average mud density received after five test runs of the experiment was 8.662 ppg which is good to be considered as a good drilling fluid.

Improving the rheological and fluid loss properties of the water-based mud using wheat flour

This study aims to evaluate the effect of wheat flour as a natural and environmentally friendly material on the properties of water-based mud. Recently, many experiments have been conducted with various additives to improve the properties of drilling fluids. The effect of using wheat flour as a new additive to drilling fluid was studied to improve rheological and filtration properties. In the laboratory several samples of water-based mud were prepared, different concentrations of wheat flour from 1 wt% to 7 wt% were added to the mud and tested by using a Fann 35 viscometer, 140 Fann Mud balance, and an API LT-LP filter press. The results showed that adding 7 wt% of wheat flour was the optimal concentration. It was found that the apparent viscosity and yield point increased by 50% and 35%, respectively, when 7 wt% of wheat flour was added to the water-based drilling fluid. Likewise, the fluid loss rate was reduced by 25% when using the same concentration of wheat flour.

Automated Surface Measurements of Drilling Fluid Properties: Field Application in the Permian Basin

Summary Accurate and frequent mud checking is essential for optimum drilling operations. Careful measurement and maintenance of drilling fluid properties (density and rheology) maintain the primary well control barrier and optimize fluid hydraulics and hole-cleaning ability. However, a full mud report while drilling is provided only once or twice a day. Moreover, the measurements are mostly performed using traditional equipment. Test interpretation is subjective and might be biased and difficult to verify independently. In this paper, we present an automated mud skid unit (MSU), which performs continual drilling fluid sampling and measurements at variable temperatures. The unit provides the non-Newtonian rheological constants characterizing a yield-power law fluid as well as the real-time friction factor and critical Reynolds number using a pipe-viscometer measurement approach. Other important fluid properties such as pressurized density, oil/water ratio, and temperature are provided using high-quality in-line sensors. The unit is controlled by a programmable logic controller coupled with a Linux operating system for data analysis. The system sends real-time data to WITSML data servers and provides detailed mud reports to engineers working either on-site or remotely. The MSU was deployed in the Permian Basin by an independent operator for automated mud monitoring during unconventional shale drilling operations. Rheology, density, and phase content measurements were compared with conventional mud reports provided by the on-site mud engineer. High accuracy (error &amp;lt; 5%) was observed in mud rheology tests. The pressurized mud-density measurements provided by the MSU proved to be more accurate than nonpressurized mud balance measurements, which were affected by mud aeration. Moreover, the MSU provided mud check data 25 times more frequent than those generated by the mud engineer at temperatures of 50 and 65.5°C. Drilling-fluid-related issues, such as chemical overtreatment as well as sudden changes in mud density, rheology, and oil/water ratio, were reported immediately to the drilling crew. This paper provides details about the measurement technology as well as the results from the field deployment of the MSU.

Effect of Formation Cutting’s Mechanical Properties on Drilling Fluid Properties During Drilling Operations

In drilling operations, the fine drilled cutting are mixed with the drilling fluid. As a result, the properties of the drilling fluid, such as density and rheological properties, will change based on the cutting properties. Previous studies investigated the effect of rock type with different loadings on the drilling fluid properties. However, the effect of cutting’s mechanical properties variation was not addressed. In this paper, the effect of variation in cutting’s mechanical properties on the drilling fluid properties was investigated in sandstone reservoir. Particles of sandstone formation core samples with different compressive strength (UCS) and different Young’s modulus (E) were mixed, in different percentages, with the drilling fluid. The mechanical properties of the cuttings were determined in the laboratory using destructive method. The drilling fluid density and rheological properties were measured using mud balance and 900-Viscometer®, respectively. The results of this work showed that, for sand content less than 10 wt%, the mechanical properties of the drilled cutting have no effect on drilling fluid properties. The effect of the mechanical properties of the drilled cutting becomes more significant for sand content greater than 10 wt%. In this range of sand content (> 10 wt%), for a constant UCS, drilled cutting with a smaller Young’s modulus have a higher effect on the drilling fluid rheological properties compared to drilled cutting with a larger Young’s modulus. On the other hand, for a constant E, drilled cutting with larger UCS showed a higher effect on the drilling fluid rheological properties compared to drilled cutting with smaller UCS values.

Real-time determination of rheological properties of high over-balanced drilling fluid used for drilling ultra-deep gas wells using artificial neural network

Drilling depleted and ultra-deep gas reservoirs required special drilling fluids which should be capable of bridging along the walls of the well and withstands a high differential pressure. High-overbalanced water-based drilling fluid (HOBWBDF) is one of the most common drilling fluid used to drill the ultra-deep gas wells. Drilling fluids properties such as yield point (YP), plastic viscosity (PV), apparent viscosity (AV), flow behavior index (n) and consistency index (k) are very vital inputs in managing rig hydraulics, margins of surge and swab pressure, equivalent circulation density (ECD) and hole cleaning. There is a need to develop a new technique to estimate the rheological properties in real-time using the frequent measurements of mud density and Marsh funnel viscosity, which are carried out more frequently (every 15–20 min).The main goal beyond this work is to build novel empirical models that are capable of predicting the above-mentioned rheological properties of high over-balanced water-based drilling fluid (HOBWBDF) in real-time for the first time. The models are built based on only two inputs which are the mud weight from the mud balance test and Marsh funnel viscosity measured by the Marsh funnel test. More than 1200 field measurements of rheological properties were used to feed an artificial neural network in order to develop new novel empirical models.The developed models using the ANN technique showed high accuracy for predicting the different drilling fluid rheological properties. The obtained results showed a maximum average absolute percentage error (AAPE) less than 8% with a correlation coefficient higher than 93%. The main advantages of these models are their inexpensiveness as there is no need for additional equipment to be added to the rig site. Moreover, these models would greatly help the drilling engineers to manage the ECD, surge and swab pressure and hole cleaning which in return will be reflected positively on the drilling performance.

Proposing a new biodegradable thinner and fluid loss control agent for water-based drilling fluid applications

Drilling fluid conventional additives have severe drawbacks on the environment and personnel safety. Biodegradable environmentally friendly alternatives will eliminate these drawbacks. In this study, the food waste of potato peel powder is proposed as a biodegradable alternative drilling fluid additive. Full-set measurements of laboratory tests were conducted to evaluate the influence of adding diverse concentrations of potato peel powder on the entire specifications of drilling fluids. A reference mud sample was made, and different concentrations of potato peel powder additives were added to different samples, and measurements were taken using mud balance, viscometer, low-pressure and low-temperature filter press, chemical titration, and other standard drilling fluid laboratory equipment. All results were recorded and compared to the reference mud sample. The findings showed that potato peel powder has tangibly enhanced the viscosity components by decreasing the yield point and gel strength and increasing the plastic viscosity of the drilling fluid. Potato peel powder revealed the feasibility to be invested as a filtration control additive as it mitigated the fluid loss and improved the filter cake thickness. Potato peel powder increased the sodium chloride and reduced the resistivity, alkalinity, and calcium ions with very little effect on mud weight and solid content. All the tests showed that potato peel powder can be used as an alternative to non-biodegradable additives such as resinex to enhance drilling fluid properties while protecting the environment and personnel.

X-ray densitometry of drilling fluids at the rig standpipe

Fluids used during well construction operations serve as a primary barrier for well control, with the fluid density generating sufficient hydrostatic pressure in the fluid column to control downhole formation fluids and gas. Real-time density measurement at the well inlet, where high pressures of many thousands of psi can occur, is highly desirable in order to maintain well control. This improved characterization of the well bore pressure profile allows one to drill wells with narrow drilling margins without non-productive time from well control events, resulting in safer and more cost-effective well construction operations. Gamma ray densitometers are suitable measuring devices for high-pressure density measurement. Typical flow conditions encountered at the inlet, such as a fully filled pipe and a homogeneously mixed mud, are very conducive to their use. In-spite of their high measurement accuracy and relatively fast response times, however, these meters have seen limited adoption in field. This is primarily because the meters come with safety concerns due to the radioactive source required for gamma ray generation. Additionally, the source has to be tracked throughout its life and properly handled during storage, transportation, installation and disposal. Given these concerns and challenges, a majority of oil and gas operating and service companies use manual density measurements at the mud pits using a pressurized mud balance. To help change this rather antiquated and infrequent practice that relies on manual labor, this paper evaluates the feasibility of using a non-radioactive, X-ray based densitometer as an alternative to the gamma ray meter. X-ray densitometry works on the same proven principles as gamma ray densitometry, without the latter's drawbacks. Two X-ray methods, an empirical method and a model-based method (inspired by a technique used in the medical field known as single X-ray absorptiometry) are presented here. Real-time density measurements on the high pressure line with an accuracy of 99% or better and a measurement frequency of 1 Hz are feasible using these methods.

Performance Evaluation of Commercial Lost Circulation Materials

Abstract Lost circulation can be considered as one of the crucial drilling problems during drilling a hydrocarbon well and can cause a lot of negative consequences including formation damage, loss of well and requires a lot of money to solve this problem. There are many ways to mitigate this issue and one of them is to use lost circulation materials and mix together with the drilling fluids. However, there are many types of lost circulation materials and their performance varies depending on the condition. Some of the most common commercial lost circulation materials are nut plug and corn cob. In this paper, the evaluation of these two materials were studied and laboratory investigation was done to evaluate the performance in terms of rheology and filtration properties. The samples were prepared and mixed in the water-based drilling fluid with different sizes (fine, medium and coarse) and another drilling fluid were also prepared with combination of fine and medium sizes of the samples. The density, rheology and filtration properties of the mud were tested by using pressurized mud balance, viscometer and filtration tester respectively. The results show that there is no exact difference in terms of plastic viscosity, yield point and gel strength between nut plug and corn cob. However, nut plug shows a slightly higher result compared to corn cob in those three parameters. In terms of filtration properties, nut plug shows less filtrates produced while compared to corn cob but mud cake produced by corn cob is slightly thinner than nut plug. In terms of sizes, fine sizes of nut plug and corn cob yield better filtration properties compared to other sizes. However, the filtration results are better when fine and medium sizes of the nut plug and corn cob samples were combined together. In conclusion, the correct sizes of the lost circulation materials should be determined and chosen properly in order to get good performance of the drilling fluids.

CTAB grafted PAM gel and its application in drilling fluid

Cetyltrimethyl ammonium bromide (CTAB) grafted Polyacrylamide (PAM) gel has been used to control fluid loss for high performance drilling fluid with increased thermal stability. PAM complex was prepared by treating PAM with CTAB by green chemistry techniques. Characterization of PAM complex was carried out using FTIR, scanning electron microscope (SEM). Dispersed inhibitive drilling fluid system was formulated using PAM complex in KCl solution with attapulgite (as viscosifier), chrome free lignosulphate (as dispersant) and oxygen scavenger. rheology of an inhibitive drilling fluid has been studied using Fann VG meter, Mud balance, API fluid loss apparatus. Mud cake was analysed using SEM, EDX to study the PAM complex linkage with attapulgite. Addition of PAM complex improves the rheology of the mud system with increased fluid retention capacity. PAM complex is stable upto 160 °C, where generally PAM degrades thermally resulting in performance decrease of desirable rheological properties and filtration control of the fluid. PAM complex is believed to form coacervate phase which increases the fluid retention capacity of the system, from effective bridging with attapulgite, high salt tolerance, moderate temperature stability, in the inhibitive mud system.