Novel Analytical Solution and Type-Curves for Lost-Circulation Diagnostics of Drilling Mud in Fractured Formation

2021 ◽  
Author(s):  
Rami Albattat ◽  
Hussein Hoteit
Keyword(s):  
Analytical Solution ◽  
Diagnostic Tool ◽  
Drilling Fluid ◽  
Fractured Reservoirs ◽  
Dimensionless Time ◽  
Type Curves ◽  
Lost Circulation ◽  
Dimensionless Groups ◽  
Drilling Operations ◽  
Mud Loss

Abstract Loss of circulation is a major problem that often causes interruption to drilling operations, and reduction in efficiency. This problem often occurs when the drilled wellbore encounters a high permeable formation such as faults or fractures, leading to total or partial leakage of the drilling fluids. In this work, we present a novel semi-analytical solution and type-curves that offer a quick and accurate diagnostic tool to assess the lost-circulation of Herschel-Bulkley fluids in fractured media. Based on the pressure and mud loss trends, the tool can estimate the effective fracture conductivity, the cumulative mud-loss volume, and the leakage period. The behavior of lost-circulation into fractured formation can be assessed using analytical methods that can be deployed to perform flow diagnostics, such as the rate of fluid leakage and the associated fracture hydraulic properties. In this study, we develop a new semi-analytical method to quantify the leakage of drilling fluid flow into fractures. The developed model is applicable for non-Newtonian fluids with exhibiting yield-power-law, including shear thickening and thinning, and Bingham plastic fluids. We propose new dimensionless groups and generate novel dual type-curves, which circumvent the non-uniqueness issues in trend matching of type-curves. We use numerical simulations based on finite-elements to verify the accuracy of the proposed solution, and compare it with existing analytical solutions from the literature. Based on the proposed semi-analytical solution, we propose new dimensionless groups and generate type-curves to describe the dimensionless mud-loss volume versus the dimensionless time. To address the non-uniqueness matching issue, we propose, for the first time, complimentary derivative-based type-curves. Both type-curve sets are used in a dual trend matching, which significantly reduced the non-uniqueness issue that is typically encountered in type-curves. We use data for lost circulation from a field case to show the applicability of the proposed method. We apply the semi-analytical solver, combined with Monte-Carlo simulations, to perform a sensitivity study to assess the uncertainty of various fluid and subsurface parameters, including the hydraulic property of the fracture and the probabilistic prediction of the rate of mud leakage into the formation. The proposed approach is based on a novel semi-analytical solution and type-curves to model the flow behavior of Herschel-Bulkley fluids into fractured reservoirs, which can be used as a quick diagnostic tool to evaluate lost-circulation in drilling operations.

scholarly journals Modeling Lost-Circulation into Fractured Formation in Rock Drilling Operations

2021 ◽  
Author(s):  
Rami Albattat ◽  
Hussein Hoteit
Keyword(s):  
Analytical Modeling ◽  
Drilling Fluid ◽  
Fluid Loss ◽  
Fracture Conductivity ◽  
Type Curves ◽  
Bingham Plastic ◽  
Lost Circulation ◽  
Rock Formations ◽  
Solution Methods ◽  
Drilling Operations

Loss of circulation while drilling is a challenging problem that may interrupt drilling operations, reduce efficiency, and increases cost. When a drilled borehole intercepts conductive faults or fractures, lost circulation manifests as a partial or total escape of drilling, workover, or cementing fluids into the surrounding rock formations. Studying drilling fluid loss into a fractured system has been investigated using laboratory experiments, analytical modeling, and numerical simulations. Analytical modeling of fluid flow is a tool that can be quickly deployed to assess lost circulation and perform diagnostics, including leakage rate decline and fracture conductivity. In this chapter, various analytical methods developed to model the flow of non-Newtonian drilling fluid in a fractured medium are discussed. The solution methods are applicable for yield-power-law, including shear-thinning, shear-thickening, and Bingham plastic fluids. Numerical solutions of the Cauchy equation are used to verify the analytical solutions. Type-curves are also described using dimensionless groups. The solution methods are used to estimate the range of fracture conductivity and time-dependent fluid loss rate, and the ultimate total volume of lost fluid. The applicability of the proposed models is demonstrated for several field cases encountering lost circulations.

scholarly journals Numerical Modeling of Foam Drilling Hydraulics

2007 ◽  
Vol 4 (1) ◽  
pp. 103 ◽  
Author(s):  
Ozcan Baris ◽  
Luis Ayala ◽  
W. Watson Robert
Keyword(s):  
Drilling Fluid ◽  
Operating Conditions ◽  
Drilling Fluids ◽  
Drilling Mud ◽  
Lost Circulation ◽  
Pressure Profiles ◽  
Drilling Operations ◽  
Parametric Studies ◽  
Bit Life ◽  
Foam Drilling

The use of foam as a drilling fluid was developed to meet a special set of conditions under which other common drilling fluids had failed. Foam drilling is defined as the process of making boreholes by utilizing foam as the circulating fluid. When compared with conventional drilling, underbalanced or foam drilling has several advantages. These advantages include: avoidance of lost circulation problems, minimizing damage to pay zones, higher penetration rates and bit life. Foams are usually characterized by the quality, the ratio of the volume of gas, and the total foam volume. Obtaining dependable pressure profiles for aerated (gasified) fluids and foam is more difficult than for single phase fluids, since in the former ones the drilling mud contains a gas phase that is entrained within the fluid system. The primary goal of this study is to expand the knowledge-base of the hydrodynamic phenomena that occur in a foam drilling operation. In order to gain a better understanding of foam drilling operations, a hydrodynamic model is developed and run at different operating conditions. For this purpose, the flow of foam through the drilling system is modeled by invoking the basic principles of continuum mechanics and thermodynamics. The model was designed to allow gas and liquid flow at desired volumetric flow rates through the drillstring and annulus. Parametric studies are conducted in order to identify the most influential variables in the hydrodynamic modeling of foam flow. 

Nano-Enhanced Drilling Fluids: Pioneering Approach to Overcome Uncompromising Drilling Problems

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
J. Abdo ◽  
M. Danish Haneef
Keyword(s):  
Rheological Properties ◽  
Size Distribution ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Lost Circulation ◽  
Drilling Operations ◽  
Cost Efficient ◽  
A Chain ◽  
Size Distribution Of Particles

The idea of pushing the limits of drilling oil and gas wells by improving drilling fluids for undemanding and cost efficient drilling operations by extracting advantage from the wonders of nanotechnology forms the basis of the work presented here. Foremost, in order to highlight the significance of reducing the size distribution of particles, new clay ATR which has a chain like structure and offers enormous surface area and increased reactivity was tested in different sizes that were chemically and mechanically milled. Bentonite which is a commonly used drilling fluid additive was also tested in different particle size distribution (PSD) and rheological properties were tested. Significant reduction in viscosity with small sized particles was recorded. The tested material called ATR throughout this paper is shown to offer better functionality than bentonite without the requirement of other expensive additives. Experiments were performed with different size distributions and compositions and drastic changes in rheological properties are observed. A detailed investigation of the shear thinning behavior was also carried out with ATR samples in order to confirm its functionality for eliminating the problem of mechanical and differential pipe sticking, while retaining suitable viscosity and density for avoidance of problems like lost circulation, poor hole cleaning and inappropriate operating hydrostatic pressures.

Wellbore Shielding Technique Increases Operative Window, Avoiding Formation Instability and Losses, Minimizing NPT, and Optimizing Drilling Operations in the Unconventional Plays

2021 ◽  
Author(s):  
Gaston Lopez ◽  
Gonzalo Vidal ◽  
Claus Hedegaard ◽  
Reinaldo Maldonado
Keyword(s):  
Drilling Fluid ◽  
Drilling Fluids ◽  
Wellbore Instability ◽  
Lost Circulation ◽  
Drilling Performance ◽  
Drilling Parameters ◽  
Vaca Muerta ◽  
Drilling Operations ◽  
Fracture Gradient ◽  
Vaca Muerta Formation

Abstract Losses, wellbore instability, and influxes during drillings operations in unconventional fields result from continuous reactivity to the drilling fluid causing instability in the microfractured limestone of the Quintuco Formation in Argentina. This volatile situation becomes more critical when drilling operations are navigating horizontally through the Vaca Muerta Formation, a bituminous marlstone with a higher density than the Quintuco Formation. Controlling drilling fluids invasion between the communicating microfractures and connecting pores helps to minimize seepage losses, total losses, wellbore fluid influxes, and instabilities, reducing the non-productive time (NPT) caused by these problems during drilling operations. The use of conventional sealants – like calcium carbonate, graphite, asphalt, and other bridging materials – does not guarantee problem-free drilling operations. Also, lost circulation material (LCM) is restricted because the MWD-LWD tools clearances are very narrow in these slim holes. The challenge is to generate a strong and resistant seal separating the drilling fluid and the formation. Using an ultra-low-invasion technology will increase the operative fracture gradient window, avoid fluid invasion to the formation, minimize losses, and stop the cycle of fluid invasion and instability, allowing operations to maintain the designed drilling parameters and objectives safely. The ultra-low-invasion wellbore shielding technology has been applied in various fields, resulting in significantly improved drilling efficiencies compared to offset wells. The operator has benefited from the minimization of drilling fluids costs and optimization in drilling operations, including reducing the volume of oil-based drilling fluids used per well, fewer casing sections, and fewer requirements for cementing intervals to solve lost circulation problems. This paper will discuss the design of the ultra-low-invasion technology in an oil-based drilling fluid, the strategy for determining the technical limits for application, the evaluation of the operative window with an increase in the fracture gradient, the optimized drilling performance, and reduction in costs, including the elimination of NPT caused by wellbore instability.

Investigation into Permeability and Bearing Strength of Plugging Zone Formed by Lost Circulation Materials

2012 ◽  
Vol 190-191 ◽  
pp. 504-508
Author(s):  
Song Li ◽  
Yi Li Kang ◽  
Li Jun You ◽  
Da Qi Li
Keyword(s):  
Calcium Carbonate ◽  
Drilling Fluid ◽  
Soap Film ◽  
Fracture Width ◽  
Lost Circulation ◽  
Bearing Strength ◽  
Confining Pressures ◽  
Mud Loss ◽  
Lost Circulation Materials ◽  
Relationship Of

Mud loss while drilling fractured formations is a major problem for drilling operating. It is a key to successful temporary sealing technology that lost circulation materials (LCM) can quickly form the plugging zone in the fractures. The permeability of plugged zone influences its bearing strength, as drilling fluid can penetrate and break it, causing it destabilizing and then failure of lost circulation controlling. With the soap film flowmeter, designing different LCM under variable confining pressures, considering the matching relationship of grain diameters and fracture width is (0.5～1):1, analyzing the permeability of plugging zones with different materials. The results indicated that permeability of plugging zone with peanut grains is lower than that of calcium carbonate, but its bearing strength is not as good as that of calcium carbonate, while using merely single LCM. Comparing other materials, the ideal plugging zone is formed with the mixture of peanut grains and calcium carbonate, which has the lowest permeability as well as the bearing strength. The mixture of matching calcium carbonate and smaller peanut grains, comparing to the width of fracture could stands 5 MPa of pressure difference at normal temperature, and 3.9 MPa at 80°C temperature in laboratory. To some extent, it can meet the needs of temporary sealing technology and successfully deal with lost circulation, which demands plugged tightly and bilateral pressurization.

A Change Point Detection Approach for Intelligent Real-Time Identification of Lost Circulation Events During Drilling Operations

2021 ◽  
Author(s):  
Francesco Cannarile ◽  
Stefano Montoli ◽  
Giuseppe Giliberto ◽  
Mauro Suardi ◽  
Benedetta Di Bari ◽  
...  
Keyword(s):  
Change Point ◽  
Structural Changes ◽  
Prediction Models ◽  
Detection System ◽  
Drilling Fluid ◽  
Change Point Detection ◽  
Lost Circulation ◽  
Drilling Operations ◽  
Point Detection ◽  
Mud Flow

Abstract Lost circulation is a challenging aspect during drilling operations as uncontrolled flow of wellbore fluids into formation can expose rig personnel and environment to risks. Further, the time required to regain the circulation of drilling fluid typically results in unplanned Non-Productive Time (NPT) causing undesired amplified drilling cost. Thus, it is of primary importance to support drilling supervisors with accurate and effective detection tools for safe and economic drilling operations. In this framework, a novel lost circulation intelligent detection system is proposed which relies on the simultaneous identification of decreasing trends in the paddle mud flow-out and standpipe pressure signals, at constant mud flow-in rate. First, mud flow-out and standpipe pressure signals underlie cubic-spline-based smoothing step to remove background noise caused by the measurement instrument and the intrinsic variability of the drilling environment. To identify structural changes in the considered signals, a nonparametric kernel-based change point detection algorithm is employed. Finally, an alarm is raised if flow-out and standpipe pressure decreasing trends have been detected and their negative variations are below prefixed threshold values. The proposed intelligent lost circulation detection system has been verified with respect to historical field data recorded from several Eni wells located in different countries. Results show that the proposed system satisfactorily and reliably detects both partial and total lost circulation events. Further, its integration with already existing Eni NPT prediction models has led to a significant improvement in terms of events correctly triggered.

A Big Question for Digital Experts: What Is the Driller Trying To Do?

2021 ◽  
Vol 73 (06) ◽  
pp. 29-30
Author(s):  
Stephen Rassenfoss
Keyword(s):  
Situational Awareness ◽  
Drilling Fluid ◽  
Construction Engineering ◽  
Lost Circulation ◽  
Drilling Optimization ◽  
Fluid Properties ◽  
Drilling Operations ◽  
Multiple Devices ◽  
Drilling Conditions ◽  
Fluid Losses

Digital drilling experts spend a lot of time wondering “what was the driller thinking?” They are not being sarcastic. The question matters for those doing analysis or writing control algorithms because the significance of readings, such as level of torque at any moment, depends on what the driller is doing at the time. The interpretation is different if the rig is drilling, where significant torque is required, or reaming, where the resistance is likely minimal. “During the reaming process, a spike in torque indicates something altogether different from a similar spike while drilling. So, the machine must recognize at least these two states: drilling and reaming,” said Fred Florence, a drilling consultant. He is among a group of drilling automation advocates who put rig state on a short list of issues that must be addressed to make it possible to create drilling systems where multiple devices can read and react in sync to changing drilling conditions. In other words, they want to know the information in the driller’s head now, said Moray Laing, director of digital value well construction engineering for Halliburton. That means an automated device needs to know what the driller is doing and also be aware of concerns that could require quick reactions. “Unless we can give it the same situational awareness of a human, it will not be able to manage the complexity of the process,” said Darryl Fett, Total’s manager of research drilling and wells in Houston. Rig state differences also plague those trying to analyze drilling data who need to know what else was going on at the time. They struggle with multiwell data where different methods of calculating the rig state were used. Drillers leave a record of their work in drilling logs. But this after-the-fact report typically lacks the precise timing sought by digital analysts using high-frequency data to analyze events that can happen suddenly. “A data scientist working on drilling will tell you that one of their biggest pains is someone will ask them to build a model on lost circulation and here is some data,” Laing said. That analysis is not possible unless someone can offer details about when the fluid losses began, how long they lasted, and other bits of context that might matter, such as the drilling fluid properties at the time. When asked for a basic explanation of the rig state, Crispin Chatar, drilling subject matter expert for Schlumberger, compared it to bringing a car that has been overheating to the shop. The mechanic will ask what was happening when the trouble began. Did the trouble start while driving fast on a freeway? While stuck in traffic? Did it happen after the radiator fluid warning light went on? “Every single engineer who works in drilling optimization, drilling analytics, or any one of our remote operation centers uses rig state to quickly and clearly understand what is going on at the well-site in terms of drilling operations or what the system might be seeing downhole,” Chatar said.

USING DURIAN RIND AS BRIDGING MATERIAL TO OVERCOME FLUID LOSS AND LOST CIRCULATION PROBLEMS IN DRILLING OPERATIONS

2016 ◽  
Vol 78 (8) ◽  
Author(s):  
Nor Fatihah Abdul Majid ◽  
Issham Ismail ◽  
Mohd Fauzi Hamid
Keyword(s):  
Drilling Fluid ◽  
Filter Press ◽  
Fluid Loss ◽  
Lost Circulation ◽  
Water Based ◽  
Drilling Operations ◽  
Excellent Control ◽  
Induced Fractures ◽  
Loss Control ◽  
Durian Rind

Lost circulation is one of the drilling operational problems. It refers to the total or partial loss of drilling fluid into highly permeable zones or natural or induced fractures. This problem is likely to occur when the hydrostatic head pressure of drilling fluid in the hole exceeds the formation pressure. Today, managing lost circulation remains a significant challenge to oilwell drilling operations because it may contribute to high non-productive time. It is imperative to note that the overbalance pressure situation also can cause the invasion of mud filtrate into production zones which will result in formation damage. To address these problems, an experimental investigation has been done on durian rind as an alternative fluid loss and lost circulation materials in water-based mud. Durian rind was selected as a mud loss control material because it contains close to 20% pectin which may complement the formation of high quality mat-like bridges across openings of the formation. The test involved the use of standard mud testing equipment and a lost circulation test cell. Durian rind powder was prepared by cleaning and cutting the durian rind into small pieces of 1 to 2 cm, and then dried them in an oven at 60°C for 48 hours before grinding into five different sizes from coarse to ultra-fine while Hydro-plug, the commercial lost circulation material was supplied by Scomi Energy. The fluid loss test was conducted using a standard low pressure filter press while the bridging test was carried out at 100 psi of pressure difference and ambient temperature using a lost circulation cell. Fine durian in the water-based mud gave the best fluid loss control compared to coarse durian rind, fine and coarse Hydro-plug. The experimental results also showed that at 15 lb/bbl (42.8 kg/m3) optimum concentration, coarse and intermediate durian rind have outperformed Hydro-plug by showing an excellent control of mud losses in 1 and 2 mm simulated fractures.

scholarly journals Drilling Fluid and Cement Slurry Design for Naturally Fractured Reservoirs

2021 ◽  
Vol 11 (2) ◽  
pp. 767
Author(s):  
Nediljka Gaurina-Međimurec ◽  
Borivoje Pašić ◽  
Petar Mijić ◽  
Igor Medved
Keyword(s):  
Drilling Fluid ◽  
Fractured Reservoirs ◽  
Naturally Fractured Reservoirs ◽  
Cement Slurry ◽  
Lost Circulation ◽  
Managed Pressure Drilling ◽  
The World ◽  
Naturally Fractured ◽  
Induced Fractures ◽  
Bottomhole Pressure

For years, drilling engineers have been faced with the challenge of drilling wells through naturally fractured reservoirs that are present around the world. During drilling, the pressure at the bottomhole of a well is frequently intentionally higher than formation pressure, which can result in the loss of mud in surrounding rocks. During well cementing, the bottomhole pressure is even higher than it is during drilling, because the cement slurry density is higher than the density of the mud. Therefore, if natural or induced fractures in the surrounding rocks are not plugged during drilling, the cement slurry can be lost to them, reducing their permeability which is undesirable in the case of a pay zone. To prevent the loss of circulation and the related consequences, it is necessary to apply good drilling and cementing practices and to use adequate methods and carefully selected materials for plugging the loss zones. The aim of this article is to give an overview of the preventive and corrective methods that can be applied in drilling and cementing through fractured zones as well as improvements in drilling and cementing technology to avoid lost circulation issues (e.g., aerated drilling fluid, casing while drilling, managed pressure drilling, expandable tubulars, lightweight cement slurries, etc.).

scholarly journals Assessing the Relation between Mud Components and Rheology for Loss Circulation Prevention Using Polymeric Gels: A Machine Learning Approach

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1377
Author(s):  
Musaab I. Magzoub ◽  
Raj Kiran ◽  
Saeed Salehi ◽  
Ibnelwaleed A. Hussein ◽  
Mustafa S. Nasser
Keyword(s):  
Machine Learning ◽  
Rheological Properties ◽  
Nearest Neighbor ◽  
Drilling Fluid ◽  
Gradient Boosting ◽  
K Nearest Neighbor ◽  
Wide Range ◽  
Machine Learning Approach ◽  
Drilling Operations

The traditional way to mitigate loss circulation in drilling operations is to use preventative and curative materials. However, it is difficult to quantify the amount of materials from every possible combination to produce customized rheological properties. In this study, machine learning (ML) is used to develop a framework to identify material composition for loss circulation applications based on the desired rheological characteristics. The relation between the rheological properties and the mud components for polyacrylamide/polyethyleneimine (PAM/PEI)-based mud is assessed experimentally. Four different ML algorithms were implemented to model the rheological data for various mud components at different concentrations and testing conditions. These four algorithms include (a) k-Nearest Neighbor, (b) Random Forest, (c) Gradient Boosting, and (d) AdaBoosting. The Gradient Boosting model showed the highest accuracy (91 and 74% for plastic and apparent viscosity, respectively), which can be further used for hydraulic calculations. Overall, the experimental study presented in this paper, together with the proposed ML-based framework, adds valuable information to the design of PAM/PEI-based mud. The ML models allowed a wide range of rheology assessments for various drilling fluid formulations with a mean accuracy of up to 91%. The case study has shown that with the appropriate combination of materials, reasonable rheological properties could be achieved to prevent loss circulation by managing the equivalent circulating density (ECD).

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