Drilling Mud Research Articles

Determination of the thermal state of a block gravel filter during its transportation along the borehole

Purpose. Development of a methodology for determining the thermal state of block inverse gravel filters manufactured using low-temperature technology during their transportation in a well based on computer and mathematical modeling. Methods. The study of hydrodynamic processes occurring during the transportation of the filter in the borehole, as well as the calculation of thermal fields in the filter body, was performed using the Ansys Fluent software package. To determine the effective thermophysical characteristics of the filter, the approaches of the heat transfer theory in porous media were applied. To investigate the thermal conditions of the filter at heat exchange with well fluid, the use of analytical solution of the heat conduction problem in a cylindrical shell, taking into account the properties of porous dispersed water-saturated medium, is proposed. Findings. The methodology for calculating the thermal state of a gravel filter during its operation in a well has been developed. For estimation of the filter surface temperature, the expression obtained on the basis of the analytical solution of the heat conduction equation, taking into account the characteristics of the porous filter medium, is proposed. Hydrodynamic and thermal fields in the borehole and the filter body during the filter transportation process in the borehole have been obtained. Originality. For the first time, the problem of heat exchange of a gravel inversion filter, manufactured by low-temperature technology in a well is considered. The influence of hydrothermal conditions in the well on the process of filter heating during its transportation in the well is shown. The hydrodynamic fields during the flow of the drilling mud around the inverse gravel filter are determined. Practical implications. The proposed approaches and results of the study allow to determine and can be used in the development of technological regulations for the use of block gravel filters produced by low-temperature technology for the equipment of hydrogeological wells. The methodology for modelling the process of two-phase inversion transition of aggregate state of the binding agent during transportation of inverted block-type gravel filter during well construction has been developed.

Integration of geological and well log and geomechanical modeling toward a safe mud weight for wellbore stability: A case study of Ruby field, Blocks 01&02, Cuu Long basin

There is a high density of drilled wells in Blocks 01&02 which is a part of the Cuu Long basin. The geological settings of this area have undergone a complicated evolution, resulting in heterogeneous lithology and variable stresses. Consequently, drilling activities in the Ruby oil field have faced numerous challenges, such as stuck pipe, gas kick, mud loss, and even lost well, etc. leading to substantial time and financial setbacks. It is essential to thoroughly understand the geomechanical characteristics of Ruby field to ensure safe operation and optimize drilling. In this paper, several downhole geophysical data sets such as wireline logging data as gamma ray (GR), density log (RHOB), neutron (NPHI), compression/shear sonic travel time (DTC/DTS), image formation log (FMI), pressure test (MDT) and leak of test (LOT, XLOT) are used to construct the 1D geomechanical model. The objective of this modelling is to compute parameters of pore pressure, vertical stress, horizontal stress, elastics properties, rock strengths. Then, these parameters are used to analyze the wellbore stability and to recommend appropriate drilling mud weights for the wells under study. This analysis can subsequently be extended to cover the entire Ruby oil field for the future drilling operations to enhance overall safety and efficiency.

Geomechanics applied to the petroleum industry: Wellbore stability, sand production, and hydraulic fracturing

This article introduces three applications of geomechanics in oil and gas industry, encompassing wellbore stability analysis, hydraulic fracturing, and sand production. In this paper, we reviewed three commonly used applications involving transforming stress values from the in situ coordinate system to the wellbore centric coordinate system, which have been published in the previous studies. Subsequently, various failure criteria are applied to these three geomechanical problems. First, wellbore stability analysis involves six distinct scenarios across different oil reservoirs. The results obtained enable the selection of appropriate drilling mud densities to prevent collapses and instability of wellbore. Second, regarding sand production modeling, three oil fields are presented as examples. The results consistently indicate instances of sand production under various well production conditions. Finally, the application of geomechanics in hydraulic fracturing is illustrated. The findings distinctly illustrate the evolutionary pattern of fracture dimensions, highlighting a consistent trend in fracture length development. Notably, the expansion phase of the fracture exhibits a rapid onset during the initial stages, followed by a transition into an exceedingly gradual propagation state.

THE PROBLEM OF PRESERVING THE RESERVOIR PROPERTIES OF PRODUCTIVE HORIZONS – THE CURRENT STATE

The reasons for the deterioration of reservoir properties of productive layers during their opening are considered. Special attention is paid to the study of geological properties of emulsions of the drilling mud filtrate – oil type. Productive deposits on the example of the fields of Southwestern Turkmenistan are characterized by a complex and ambiguous composition of rocks, waters and drilling mud and oil. Each of the components, interacting with the filtrate of the drilling mud, determines the deterioration of reservoir properties and a decrease in the flow rates of hydrocarbon fluids. Oilbased solutions were used to open productive horizons while maintaining natural permeability, as well as for drilling in particularly unstable clay saline deposits. In such solutions, the dispersion medium is represented by diesel fuel, and the dispersed phase is finely ground oxidized bitumen. The results obtained make it possible to clarify the mechanism of reducing the reservoir properties of productive formations due to the penetration of filtrate of drilling fluids, as well as to formulate new requirements for technologies, composition and properties of drilling fluids for opening productive formations.

NEW DRILLING METHOD, DEVELOPMENT OF HYDROGEOLOGICAL AND OIL WELLS WITH IMPLOSIVE EFFECT

The peculiarities of the collimation zones of the productive formation are taken into account when rotary drilling of wells using drilling mud. A brief analysis of the most common and fundamentally different decollatation procedures, such as washing wells with water, pumping and gelation, is presented. A very effective and promising method of decollatation using the implosion effect has a special influence. A detailed example of a well-known device is given with an analysis of the features of its application, as well as significant disadvantages in the form of complexity and functionality, high cost. A fundamentally different new device was developed and proposed, free from all the disadvantages of the opposite device for which the invention was requested. This eliminates the use of pumping and compressor pipes and their sealing, as well as a sealant for the neck. There is also no need for a compressor and surface wiring with numerous valves. Replacing the intake valve valve with a disc valve eliminates the possibility of closing the intake valve as a result of the influx of reservoir fluid with a high content of collating materials caused by the implosion effect. The design and functioning features of the proposed device and its individual elements are taken into account both when creating a single, and with any number of repeated implosive effects. The generation limits necessary for the explosion effect of the liquid-filled space were mathematically analyzed to prevent the case from crumpling under the hydrostatic pressure of the solution remaining in the storage space. An example of the dependence of the permissible length of empty space on the thickness of the housing column and, in particular, on the thickness of the walls is illustrated using a computer program.

PRODUCTION OF DRILLING FLUIDS BASED ON COTTON SOAPSTOCKS

For effective oil production, this is necessary to ensure high-quality drilling, opening of reservoirs. Many tasks that-arise during drilling are solved with the-help of-process fluids. The purpose of the work is to create new drilling fluids based on secondary resources, surfactants. The composition of-a new drilling mud for drilling wells is proposed. Methods. One of-the main indicators of hydrophobic emulsion solutions is filtrate output. The operational properties of the filtrate-release of hydrophobic emulsion solutions differ slightly from other indicators. When filtering hydrophobic emulsion solutions in a porous-medium, the kinetic factor associated with the-rate of formation of the filtration crust becomes of great importance. Results and discussion. The instantaneous filtrate output of-systems of hydrophobic emulsion solutions stabilized by surfactants is reduced due to the rapid formation of a bound filtration crust by means of-fast interactions, therefore, it’s strengthened by slow interaction bonds. This formation of charge-transfer complexes, electronic donor-acceptor, long-lived free stable radicals, hydrogen, covalent bonding carried out with an induction period at a close distance, determines a decrease in-the filtration yield of the solution. Conclusion. Cotton soapstocks are valuable additives in the composition of drilling fluids-to improve their operational properties. According to the limit values of the parameters, the-reagents are arranged in the following-series according to-filtrate: fatty acid salts > emultal > soapstock > tar distillation of fatty-acids. At the same time, the parameters of the hydrophobic emulsion solution are always, except for GJC and FFA, where after the limit value of their quantities, the filtrate output increases, improves with-the concentrations of-reagents.

Mineral oil-based drilling fluid formulation using biosurfactant and nanoparticles with good rheological behavior and excellent H2S scavenging capability

There are two commonly used drilling fluids, namely water-based muds (WBMs) and oil-based muds (OBMs); however, the latter type is more desirable for drilling unconventional oilfield reserves. To account for the potential encounter of hydrogen sulfide (H2S) while drilling, the utilized OBMs should contain scavenger(s) with an effective H2S mitigation capability in order to in-situ capture this very lethal and corrosive gas. To the best of our knowledge, studies on incorporating H2S scavengers in OBMs and their testing are still greatly lacking in open literature. Thus, this study contributes into the filling of this gap by preparing a mineral oil-based drilling mud (MOBM) containing potassium permanganate as a promising, widely available, safe, and cheap H2S scavenger. The MOBM also comprised other ingredients including rhamnolipid biosurfactant as an emulsifier and octadecanethiol-modified (i.e., hydrophobized) zinc nanoparticles (serving as weighting agent). These materials have not been widely utilized so far in open literature for the preparation of MOBM. The results obtained from this study demonstrated that this mud could fully scavenge H2S for up to 22.7 h (i.e., breakthrough time), and it took about 63 h for the MOBM to become fully saturated with H2S. The scavenged amounts of H2S at these times reached 324.4 and 485.8 g/barrel MOBM, respectively. The formulated MOBM also displayed an appropriate non-Newtonian shear thinning behavior, where the apparent viscosity dropped sharply from about 1.96 to 0.71 Pa.s upon increasing the shear rate to from 1 to 10 s−1, followed by a gradual decrease down to 0.31 Pa.s at a shear rate of 1000 s−1. Additionally, the formulated mud is able to dissipate a significant amount of thermal energy as inferred from its estimated high activation energy of 34.93 kJ/mol, suggesting a good thermal stability of the MOBM. The present study reveals the possibility of formulating mineral OBMs with effective H2S for safely drilling sour oil and gas reservoirs.

Design and Application of Downhole Drilling Mud Pulse Signal Transmission System

Time-efficient measurement of undisturbed formation through measurement while drilling technology is an effective means to improve drilling efficiency in deep formations and increase the drilling-encounter ratio of reservoirs. Based on the application and development trend of existing downhole signal transmission technology, a pulse signal transmission system of downhole mud while drilling is designed. The system pulse generation device adopts the structure of a positive pulse generator, which is through the internal driving circuit and hydraulic circuit of the device to drive the valve head to move to generate a mud pulse signal while using the design of a limit switch to optimize the expansion spacing of the valve head so that the generated pulse signal amplitude is close. The system uses combined encoding as the encoding method, while the ground part of the system is designed to monitor and process the collected signals. Finally, the transmission capability and accuracy of the system are tested through field experiments, and the field results show that the system can work smoothly in the downhole environment to transmit downhole data to the wellhead with small errors, which meets the design requirements and field requirements. The field applications are carried out in several wells, such as the Shixi 105 well. The results show that the system has good downhole pulse signal transmission functions such as borehole inclination measurement, which helps to promote the development of existing drilling measurement technology.

Fracture development around wellbore excavation: Insights from a 2D thermo-mechanical FDEM analysis

Insights into fracture development and excavation damaged zone (EDZ) formation around wellbore excavation sites are essential for understanding wellbore stability. In this study, a novel thermo-mechanical scheme is implemented in the 2D combined finite-discrete element method (FDEM) to investigate the fracturing process around a wellbore in a high-temperature subsurface environment. The developed scheme captures the isotropic/anisotropic thermal conduction characteristics within the rock formation. The coupled scheme and stress distributions around the wellbore subject to in-situ stress, drilling mud pressure, and temperature changes are validated by closed-form solutions. Fracture development and progressive EDZ formation by various mechanisms are analyzed. The results show that for an unsupported wellbore, fractures initiate in the region of the most severe stress concentration due to excavation unloading and constitute an EDZ that resembles the logarithmic-spiral rupture zone captured by experimental observations and Mohr-Coulomb models, resulting in potential water inrush due to the significantly increased fracture transmissivity of the EDZ and wellbore collapse. The shape and extent of the EDZ for wellbore excavation in the layered rock mass are dominated by the stress redistribution and the presence of low-strength bedding planes favorably oriented for bedding slippage. The excavation unloading-induced stresses can be effectively counteracted by properly applying drilling mud pressure, and the disturbance of the stress field occurs only within a small region, greatly reducing the extension of the EDZ. Thermal contraction of the surrounding rock due to its convective interaction with the cold drilling mud induces extra fractures around the wellbore. The extension of the EDZ is greater with increased thermal expansivity of the rock formation. Overall, the results indicate that the adopted thermo-mechanical FDEM simulation can provide unique geomechanical insight into wellbore stability behavior analysis, in which explicit consideration of the fracturing and fragmentation processes is of great significance.

Grafted graphene oxide nanoparticles as a yield point enhancer in water-based drilling fluids

Drilling fluids are used in exploration and production (E&P) for oil/gas. More recently, nanomaterial additives such as nano clay, nano-silica, nanocellulose, etc., have been of interest in improving drilling fluids' performance. Graphene and oxide (GO) nanomaterials have been attractive for oil-field applications. Furthermore, water-based drilling fluids are more environmentally desirable than oil-based fluids. This study demonstrated the successful synthesis and use of bi-facial grafted graphene oxide with two random copolymers and one block copolymer for water-based drilling mud application. The successful polymerization was verified by FTIR spectroscopy, EGA, DLS, and Raman spectroscopy. The dispersity and stability of GO-AMPS-r-DMA were tested in different water-based and oil-based solvents, indicating better dispersity and stability in water and DMF than GO. The thermal behavior of the three GO-polymer composites was studied by TGA, DSC, and EGA, showing higher stability with block copolymers than random ones. The performance of such grafted graphene materials was tested in water-based drilling fluids at simulated downhole temperatures and pressures. Results demonstrate the positive effect of these produced grafted graphene materials on mud rheological behavior at temperatures up to 350F and 10,100psi.

Cost reduction in the construction of horizontal wells by optimizing the polymer-chloride drilling mud and its reuse

One of the key tasks in oil and gas well development today is to optimize the cost of various technical processes, including the preparation of drilling muds. The article explores technological remedies to decrease the concentration of potassium chloride, which is the main inhibitor of the hydration of clay rocks, in the composition of drilling mud used for horizontal well drilling. Additionally, it was demonstrated that the drilling mud left after the initial drilling of the productive formation could be reused. Due to the fact that the interval of the horizontal section of wells is represented mainly by sandstone, the composition of the drilling mud must be refined so that the use of inhibitor reagents can be reduced. Reuse of spent drilling muds in the construction of horizontal wells reduces the consumption of multi-tonnage components without impairing the processability of the flushing fluid used. The implementation of this approach will enable the achievement of economic benefits through a reduction in expenses for the preparation of drilling mud and in the amount of drilling waste generated.

Analysis of a drilling mud-based system on the common problems related to coiled tubing application in slim-hole oil wells

Coil tubing is slim and looks like a long, continuous length of pipe made from carbon steel metal that is a lesion on spool that is 1 to 3.25 inches in diameter of 26,000 feet long. The main benefit of coil tubing in drilling operations over wireline jobs is the ability to pump chemicals through the coil and the ability to push it into the hole rather than relying on gravity. Inappropriate selection of the drilling mud is one of the contributing factors to hole problems. Different experiments were conducted to determine the mud rheology of multiple mud samples. Certain parameters, like the critical velocity, are calculated using a numerical approach for the coiled tubing applications. In addition, it is crucial to determine the pump pressure required to maintain a specific flow rate. It is noted that drilling operations become more efficient at lower plastic viscosities; however, plastic viscosity is reduced through dilution; hence, the rate of penetration is improved. Moreover, a higher yield point is capable of transporting the cuttings more effectively than a lower yield point. The critical velocity indicated the boundaries between the laminar and turbulent flow regimes. As the mud flow rate inside the tubing increased, the velocity increased, causing the shear stress at the tubing wall to increase.

The Development of Advanced Fluorescent Tracers Aimed at Drill Cuttings Labelling and Depth Correlation via Injection with Oil-Based Drilling Mud

Fast and precise geo-steering and geo-navigation upon well drilling are the key parameters for improved well targeting, optimal well placement, and maximal hydrocarbon recovery. To advance geo-steering parameters, we propose a new approach to on-site formation evaluation through the use of fluorescent tracers for drill cuttings tagging according to the depth of origin. Cuttings labelling at the drill bit site is followed by near-real-time drilling depth correlation at the well-head via a camera and AI image recognition systems. To suite the drilling process, the engineered tracers should match to the rheology of the utilized drilling mud. This study was performed to comprehensively investigate the effect of fluorescent tracers on the rheological properties of oil-based drilling mud (OBM) and to determine the optimal quantities of the tracers’ addition. We evaluated critical mud characteristics including electrical stability, thixotropic parameters, shear stress, gel strength, plastic viscosity, and yield point as prepared and in the presence of fluorescent tracers at the range of 1 to 20 wt.%. Additionally, the mud’s effects on the long-term stability of the fluorescent tracers were assessed via hot-rolling tests in conditions mimicking downhole conditions, with the aim of determining the tags’ feasibility for drill cuttings labelling applications. The study also examines the recovery potential of the tracers and their reusability in the drilling process. This investigation provides valuable insights into the potential application of fluorescent tracers for downhole drill cuttings depth correlation which will improve geo-steering works.

Air quality impacts from the development of unconventional oil and gas well pads: Air toxics and other volatile organic compounds

Unconventional oil and natural gas development (UOGD) has expanded rapidly across the United States in recent decades and raised concerns about associated air quality impacts. While significant effort has been made to quantify methane emissions, relatively few observations have been made of Volatile Organic Compounds (VOCs), especially during drilling and completion of new wells. Extensive air monitoring during development of several large, multi-well pads in Broomfield, Colorado, in the Denver-Julesburg Basin, provides a novel opportunity to examine changes in local air toxics and other VOC concentrations during well drilling and completions and production. These operations offer an especially useful case to study as several management practices were implemented to reduce emissions (e.g., electrified, grid-powered drill rigs and closed loop fluid handling systems to reduce truck traffic and limit fluid handling on the pad). With simultaneous measurements of methane and 50 VOCs from October 2018 to December 2022 at as many as 19 sites near well pads, in adjacent neighborhoods, and at a more distant reference location, we identify impacts from each phase of well development and production. Use of weekly, time-integrated canisters, a Proton Transfer Reaction Mass Spectrometer (PTR-MS), continuous photoionization detectors (PID) to trigger canister collection upon detection of VOC-rich plumes, and an instrumented vehicle, provided a powerful suite of measurements to characterize both transient plumes and longer-term changes in air quality. Prior to the start of well development, VOC gradients were small across Broomfield. Once drilling commenced, concentrations of oil and gas (O&G) related VOCs, including alkanes and aromatics, increased around active well pads. Concentration increases were clearly apparent during certain operations, including drilling, coil tubing/millout operations, and production tubing installation. Emissions of C8–C10 n-alkanes during drilling operations highlighted the importance of VOC emissions from synthetic drilling mud chosen to reduce odor impacts. More than 90 samples were collected of transient plumes. Using composition measurements, meteorological data, and information about well pad activities, these plumes were connected with specific UOGD operations including drilling, flowback, and production equipment maintenance. The chemical signatures of these plumes differed by operation type (e.g., C8–C10 n-alkanes constituted a larger fraction of measured VOCs in drilling-related plumes). Concentrations of individual, oil and gas-related VOCs in these plumes were often several orders of magnitude higher than in background air, with maximum ethane and benzene concentrations of 79,600 and 819 ppbv, respectively. Because these plumes typically impact a monitoring site for just several minutes, they are easily missed by slower-responding instruments. Study measurements highlight future emission mitigation opportunities during UOGD operations, including better control of emissions from shakers that separate drill cuttings from drilling mud, production separator maintenance operations, and periodic emptying of sand cans during flowback operations.

A thermo-mechanical simulation for the stability analysis of a horizontal wellbore in underground coal gasification

The stability analysis of horizontal wells is essential for a successful underground coal gasification (UCG) operation. In this paper, a new 3D coupled thermo-mechanical numerical modeling is proposed for analyzing the stability of UCG horizontal wells. In this model, the effect of front abutment stresses, syngas pressure, syngas temperature and thermal stresses is considered to predict the mud weight window and drilling mud pressure during UCG process. The results show that the roof caving in UCG panel has a greatest impact on the stability of horizontal well. Moreover, when the time of coal gasification is increased, the well convergence increases and for more stability it is necessary to increase the drilling mud pressure. This research was carried out on the M2 coal seam in Mazino coal deposit (Iran). The results showed that the mud weight window for horizontal well drilling is between 0 and 33 MPa. The appropriate stress for the maximum stability of the horizontal well, taking all the thermal and mechanical parameters into account, is 28 MPa. The suggested numerical method is a comprehensive and consistent way for analyzing the stability of horizontal wells in UCG sites.

EVALUATION OF THE POSSIBILITY OF USING SPENT TURBINE OIL AS A LUBRICATING ADDITIVE IN DRILLING MUD

Link for citation: Lambin A.I., Averkina E.V., Erygina A.N., Averkin N.A. Evaluation of the possibility of using spent turbine oil as a lubricating additive in drilling mud. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 10, рр. 169-178. In Rus. The relevance. The consumption of lubricants and, as a result, the volume of used oils increases annually. As a result, large volumes of them are accumulated, which require standard methods of handling them. It is known that oils, including waste ones, are used as lubricating additives to drilling mud. The practice of recent years has shown the expediency of replacing lubricating additives with used lubricating oils, which would ensure the preservation of the main and the achievement of new properties. This article presents the results of a study of micelle-forming solutions under the influence of Na and K salts on their filtration and crust-forming properties. The main aim: evaluation of the possibility of using spent turbine oil in the drilling mud as a component of a lubricating additive, as well as its effect on the main parameters of the drilling mud; study of the effect of oil, ether and salt interaction on the filtration and crust-forming properties of drilling mud. Objects: spent turbine engine oils selected at the drilling site during the construction of the well. Methods. Drilling mud indicators were measured. Water, technical oil and ether were used to form micelles. The studies were carried out using the methodology of a complete factor experiment, in which the studied effects of salt in solutions were approximated in the form of first-order polynomials. Results. By comparing the first coefficients of the polynomial models, a significant effect of sodium chloride on the rheological and filtration properties of solutions and the stickiness of their filtration films was revealed. The effect of chlorides on a group of eight solutions in different oil fractions was statistically confirmed, for which the Student and Mann–Whitney criteria were used. The paper introduces the graphical interpretation of some approximations of the equations of the effect the solution ingredients interaction on the response value.

Assessment of oil degrading ability in drilling mud by biosurfactant produced by some microbial strains

Drilling mud is generated during exploratory drilling and oilfield development, and consists of a mixture of soil, rock contaminated with oil, chemicals, and drilling fluid. It is very difficult and expensive to treat this waste source, so the biosurfactant produced by microorganisms is considered a highly effective biological treatment method. Biosurfactant is a bipolar compound that allows the dissolution of insoluble substances in water, creates an emulsion that helps microorganisms better contact the oil and easily decompose the contaminated oil. This study was carried out to evaluate the ability to degrade oil in drilling mud using biosurfactant produced by some microbial strains. The results showed that four microbial strains selected from Cat Ba, Hue and Vung Tau areas, namely Brevibacteria celere, Oligella ureolytica, Stenotrophomonas maltophilia and Paenibacillus mancerans have the capacity of decomposing oil in drilling mud. The highest emulsification index (E24) of the four strains after 5 days culture with shaking at 200 rpm, pH = 7.5, temperature 30°C, 1% NaCl, carbon source of saraline and DO were recorded at 73, 71, 52 and 59%, respectively. This result shows that biosurfactants are an active compound group with potential in oil pollution treatment in the Petroleum industry in particular and environmental pollution treatment in general.

Influence of drilling mud pulsations on well cleanout efficiency

Purpose. Determination of the influence of the non-stationary flow regime of the drilling mud on the efficiency of cleaning the wellbore in the annulus from drill cuttings. Methodology. The study on the carrying capacity of the drilling mud in a laboratory installation is carried out by simulating the process of its pulsations at different frequencies. The choice of the studied frequencies was made on the basis of previous studies. The evaluation of the influence of factors on the efficiency of rock removal was carried out using Latin experimental plans, which allowed us to evaluate the influence of the selected factors with a minimum number of experiments without losing the quality of the result. Findings. The influence of factors (mud flow rates, eccentric placement of the drill string, plastic viscosity of the drilling mud, pulsation frequency, rotation of the drill string) on the efficiency of cuttings removal along the annular space of the wellbore is analyzed. Three factors with the best interaction were found, which made it possible to build dependencies of their influence on the efficiency of rock removal on the surface. The effect of changing the frequency of pulsations of the drilling mud has been studied, and graphical dependences of their influence on the decrease in the volume of rock particles in the annular space have been obtained. Originality. Based on the results of experimental studies, the effectiveness of the impact of drilling mud pulsations on cleaning the well from rock particles has been proven. Practical value. The effectiveness of the use of drilling mud pulsations for hydrotransportation of cuttings along the horizontal section of the wellbore has been confirmed.

ENHANCING THE RHEOLOGICAL PROPERTIES OF OIL-BASED MUD THROUGH THE INCORPORATION OF POTATO STARCH

Oil-based drilling muds are effective in protecting formation integrity and resisting high temperatures, but additives are necessary to optimize their performance. This study proposes using potato starch as an additive to improve the performance of oil-based drilling mud. Potato starch was chosen because of its ability to act as a viscosifier or thickener that remains unaffected by water salinity. The research involved adding different concentrations of potato starch to a fresh oil-based drilling mud, with two Oil-to-Water Ratio (OWR) ratios, 75:25 and 80:20, employed for the two trials. Rheological testing was utilized to assess the influence of potato starch additives on the viscosity, gel strength, plastic viscosity, and yield point of drilling mud. The findings showed that the incorporation of potato starch in oil-based drilling mud can enhance its rheological values. Using potato starch as an additive offers the potential to tackle wells that have formation conditions that are brittle and sensitive to water and high temperatures. This research provides novel insights into the development of more effective and eco-friendly drilling mud formulations.

CUTTING ANALYSIS ON HORIZONTAL DRIILING USING CUTTING CARRY INDEX, CUTTING TRANSPORT RATIO AND CUTTING CONCENTRATION IN ANNULUS METHOD ON A WELL G FIELD S

The basic principle of the drilling operation is to grind the rock formations with bits which will later become drill cuttings. In this process, fluid is needed as a conveying medium, commonly known as drilling mud, because the deeper the drilling, the more drill flakes are produced. One of the prominent functions of drilling mud is lifting the drill shale up to surface. The purpose of this analysis is to quantitatively prove whether the cutting has been successfully lifted to the surface or not, and to determine the elements of the fluid’s physical properties and the drilling mud fluid’s rheology. This analysis was carried out using three methods including; the cutting carry index, which the value required is greater than one; the cutting transport ratio, which the value required is greater than 50%; and the cutting concentration in annulus, which the value required is less than 5%. If the value of the quantitative calculation already has a value above the standard, it can be concluded that the drill cuttings can be lifted optimally. The value of the cutting carry index has to be greater than one, because if it is less than one the solid value in the mud is still lacking, causing a low density so it will affect the carrying capacity of cutting in 1 gal of mud. The value of cutting concentration in annulus should not be more than 5, it is feared that if it exceeds this limit, it can affect the rate of penetration and can cause a stuck. As for the value of the cutting transport ratio should not be less than 50% because if it is less than that the hydrostatic pressure below will be large and can cause formation fractures. In this case, we will discuss the analysis of cutting removal on the 8.5 inch route at 4290 to 5174 ft depth, with a slope of 66.29o from the starting point of the borehole.