Casing Setting Depth Research Articles

Drilling Casing Design using Drilling Software at Well “Well X-01” Field “S”

Well "X-01" is a slant (J-Type) directional well and will be subjected to appropriate and technically qualified drilling casing planning in order to prevent problems such as burst, collapse, and tension that can cause increased internal and external pressure loads experienced by the casing. The methodology used in this research is document study and quantitative analysis in casing planning using Drilling Software by taking into account the loading acting on the casing, which is burst, collapse, tension, biaxial, and triaxial loads. Casing design planning for Well "X-01" is carried out by analyzing the casing setting depth based on PPFG data, considering kick tolerance, then casing planning is carried out using Drilling Software. The results of drilling casing planning inWell "X-01" Field "S" using Drilling Software, five design routes were obtained, that is conductor casing using X-52 casing; 157.5 ppf, surface casing using K-55 casing; 94 ppf, intermediate casing using K-55 casing; 54.5 ppf, kick tolerance 32.55 bbls, production casing using K-55 casing; 40 ppf, kick tolerance 42.1 bbls, and production liner using K-55 casing; 23 ppf, kick tolerance 69.08 bbls. The safety factor of each route met API standards for the durability of the selected casing. In well "X", casing planning can be a reference in the casing design process stage because optimal and safe results are obtained.

Development and evaluation of fracture gradient curve model: a case study of south-central Kazakhstan

An accurate fracture gradient value is one of the most important issues in oil and gas well design and drilling. The value of a fracture gradient is a critical parameter for determining the drilling mud weight and selecting the proper depths for setting the casing in the planning process of drilling operations. This paper proposed the new curve model of fracture gradient for the south-central Kazakhstan (central Asia) region based on the analysis of leak-off test and format integrity test results. Data from more than 400 tested wells were analysed and compared with the results of existing methods for predicting the fracture gradient and with the results from previous drilling projects in that region. By using the new curve model, the more precise values of fracture gradient are determined. Besides an improved fracture gradient model development and validation, the model's analytical expressions are presented. The article's most important results are determining the model's values of fracture gradient and providing a more accurate calculation of mud weight, less mud losses, more precise evaluations of cementing operations, better selection of the casing setting depth and improved drilling safety. [Received: February 13, 2022; Accepted: June 2, 2022]

Optimization of Drilling Well Design: A Review

Drilling well design optimization reduces total Authorization for Expenditures (AFE) by decreasing well constructing time and expense. Well design is not a constant pattern during the life cycle of the field. It should be optimized by continuous improvements for all aspects of redesigning the well depending on the actual field conditions and problems. The core objective of this study is to deliver a general review of the well design optimization processes and the available studies and applications to employ the well design optimization to solve problems encountered with well design so that cost effectiveness and perfect drilling well performance are achievable. Well design optimization processes include unconventional design(slimhole) compared with fat design, in addition to optimizing casing setting depth selection and casing string loads. Finally, we demonstrate well trajectory design considerations and optimization. The optimization process that mentioned above is significantly reduce drilling cost and time since, slimhole design with smaller casing and hole size reduce mud volume cost, steel cost and pump fuel cost. Optimum casing seat selection can ovoid serious problem such as kick and losses that increase nonproductive time (NPT) if kick tolerance and downhole pressure profile is not considered. Anticipating optimum stress loads in casing design is most effective way to reduce casing strings cost avoiding additional cost for designing with useless worst conditions. Wellbore trajectory optimization with geomechnic consideration is major concern to reduce the problem encountered with high torque, drag, formation collapse that result stuck pipe and non-productive time (NPT).

Formation interval determination method of MPD based on risk aversion and casing level optimization

MPD is one of the effective means to solve the drilling problems in deep-water and deep-stratum complex formations such as narrow pressure window. To reduce the cost, it is mostly implemented only in complex and narrow pressure window strata. However, at present, there is no scientific method to determine the MPD matching stratum interval under the “conventional + MPD” composite drilling mode. Aiming at this problem, by introducing the methods of risk quantitative evaluation and taking the principle of “avoiding risk and reducing MPD cost”, combined with the accurate ECD calculation method considering multiphase flow, this paper puts forward the accurate determination method of matching the stratum interval of MPD, which can reduce the section of MPD construction as much as possible and optimize the casing level on the premise of ensuring safety. Based on the artificial bee colony algorithm, the intelligent determination method of casing level and setting depth under the condition of pressure control is established, which can quickly and accurately obtain the maximum casing setting depth and its corresponding optimal pressure control parameters in the open-hole section. The case analysis shows that, compared with the conventional drilling mode, the “upper conventional + lower MPD” drilling method can save one layer of casing while ensuring safety. The proposed method can provide theoretical and scientific basis for the accurate calculation of MPD matching stratum interval under the “conventional + MPD” compound drilling mode and the scientific and efficient design of casing levels and setting depth under the condition of pressure control.

Geological Considerations Related to Casing setting depth selection and design of Iraqi oil wells (case study)

Well integrity is a vital feature that should be upheld into the lifespan of the well, and one constituent of which casing, necessity to be capable to endure all the interior and outside loads. The casing, through its two basic essentials: casing design and casing depth adjustment, are fundamental to a unique wellbore that plays an important role in well integrity. Casing set depths are determined based on fracturing pressure and pore pressure in the well and can usually be obtained from well-specific information. Based on the analyzes using the improved techniques in this study, the following special proposition can be projected: The selection of the first class and materials must be done correctly and accurately in accordance with the depth of casing preparation and the strategy in the considered field that must be taken into account definitely in the drilling and completion period, nevertheless correspondingly in production and upkeep, conversion to an injection well or the opposite, the plug in addition to the closing stage. Features that control the depth of the casing seat have been studied, which consist of fracture gradient, pore pressure with other issues are the surviving lithology's of rocks. Subsequently defining the casing seat can be sustained with an investigation of the determination of the suitable drilling fluid. According to the consequences of the fracture pressure and pore pressure investigation and the findings of casing setting depth by means of the bottom-up technique, the consequences are gotten to each casing for the 4 studied wells. reference point designed from the rotating table RT. For well A, the conductor casing depth is 47m, the casing surface depth is 533m, the intermediate casing setting depth is 1882 m. Finally, for the production casing depth is 3441 m. Compared to the collapse pressure method, it was found that the bottom-up method gave results that are close and similar to the real results. The results of other wells are included in the search consequences

Management Of Shallow Gas Kick At Syh-05 Well In West Java Area

SYH-05 Well Drilling Operation West Java Area, was planned to be drilled with a final depth of 1694.65 mMD / 1500 mbpl by directional well drilling. Drilling hazards on the 17½” trajectory were shallow gas, gumbo, and bit balling. Furthermore, on this trajectory, shallow gas handling and optimization of drilling were going to be executed through shallow gas kick countermeasures in the SYH-05 Well. The high gas readings from the SYH-03 Well and the SYH-04 Well are 867 units and 1275 units, respectively, at a depth of 500-520 mMD intervals.After carrying out mitigation for shallow gas mitigation, the SYH-05 Well would use a higher Mud Weight than the reference well in this study starting with MW 1.12 SG while the reference well started with MW 1.08 SG, and the use of Annular – Single Ram 21-1/ 4” 2K with 10” Ball Valve as Diverter System. Moreover, to overcome the Kick Volume which was larger than the 17-1/2” hole, a 12-1/4” Pilot Hole would be installed. Prepare High Density Mud as a Contingency Plan and 4 Mud Pumps to anticipate the implementation of High Flow Rate Dynamic Kill. In the Cementing Design process, Gas Tight Slurry Cement would be applied.Based on the Casing Setting Depth analysis in the SYH-05 well drilling operation, there were 4 trajectories, namely: Conductor Casing 20”, 0-80m; Surface Casing 13-3/8”, 80-663.69m; Production Case 9-5/8”, 663.69-1060m; and Production Liner 7”, 1060.50-1694.65m. The implementation of Well Control was aimed to tackle the shallow gas kick was successfully executed in less than 1 hour without incident or accident. Work on the 17-1/2” trajectory which was a shallow gas zone could be done with the planned timetable.Keywords: Drilling hazard, Shallow gas kick, Optimization, Countermeasures

Appraisal Well Design in "X" Oil Field

The selection of casing depths and casing design are considered one of the most critical steps in the well construction process. Inaccurate selection of casing setting depths and casing design can result in many challenges, long time and hence high well costs.
 "X" oil field was taken as a case study. There is only the exploration well X-1 drilled up to date. The 20˝ surface casing was relatively long because it was set at the top of Dammam Formation. That means deep surface hole, long trip time, large amount of mud, long surface casing, large amount of cement and hence high cost. Also, Hartha Formation was not evaluated because it is isolated with the 13 3/8" & 9 5/8" casing and the perforation through two casing was not available. Another problem, the 9 5/8˝ production casing damaged at the depth 32 m due to failure of tolerating the axial forces before or after the cement job.
 All data was inputted into the Landmark software to simulate the well. It was found that the surface casing can be set at the top of Lower Faris Formation instead of Dammam Formation. Also, The Hartha Formation can be drilled in the 12 ¼ ˝ hole and isolated by 9 5/8˝ casing instead of drilling it in the 17 ½ ˝ hole and isolating it by the 13 3/8˝ casing. It was also found that the 9 5/8˝ production casing can withstand all loads by selecting casing with higher weight.
 The cost of the modified design was also checked to study the feasibility of the modified design. It was concluded that the modified design can save around 300,000 USD for each well comparing with the design of well X-1.
 It is recommended to apply this design on the appraisal well to be drilled. If the design shows no problems, it can be considered the optimum design of appraisal and development wells to be drilled in the future. Also, the slim-hole design can be studied and an economic feasibility comparison can be made with the current and the proposed design in this study.

Casing design of the KY slim hole well in “X” Geothermal field

Geothermal exploration activities including exploration drilling are important stages in a geothermal project. The high uncertainty of the amount of reserves and costs incurred in geothermal projects is a reason for investors to be reluctant to invest at this stage. One alternative is to use slim hole drilling technology instead of using standard hole or big hole technology. Slim hole drilling technology has long been applied in Indonesia in 1993 but has not continued its application. In 2015, slim hole drilling technology began to be used again at the Ijen geothermal field, East Java. Therefore, it is necessary to review the slim hole drilling, especially the casing design and hoisting rig capacity. The purpose of this study is to design a casing for slim hole KY well drilling, namely determining the casing seat at each depth, calculating the thermal stress value which is considered in calculating burst, collapse, and tension pressures. In addition to the casing design, rig sizing calculations were carried out, especially hoisting rig capacity in field X using slim hole reflection well data in the Ijen area, East Java. The results obtained are the determination of the minimum casing setting depth for the production liner 1500 m grade L-80, production casing 680 m, grade L-80, surface casing 240 m grade K-55, and conductor casing 30 m grade K-55. the results of thermal stress analysis, the maximum temperature obtained in the production casing is 425.3ºF and the production liner is 426.67ºF.

Geomechanical analysis of horizontal wells in terms of stability for drilling — A case study from the Peri-Baltic Syneclise

This paper presents a shale gas field geomechanics case study in the Peri-Baltic Syneclise (northern Poland). Polish Oil and Gas Company drilled a vertical well, W-1, and stimulated the Silurian target. Next, a horizontal well, W-2H, drilled the Ordovician target and partially collapsed. The remaining interval was stimulated, and microseismic monitoring was performed. A second horizontal well, W-3H, was drilled at the same azimuth as W-2H, but the well collapsed in the upper horizontal section (Silurian). A geomechanical earth model was constructed that matches the drilling experiences and well failure observations found in wells W-1, W-2H, and W-3H. The field was found to be in a strike-slip faulting stress regime, heavily fractured, with weak bedding contributing to the observed drilling problems. An analysis of safe mud weights, optimal casing setting depths, and optimal drilling directions was carried out for a planned well, W-4H. Specific recommendations are made to further enhance the model in any future studies. These recommendations include data acquisition and best practices for the planned well.

Особенности выбора глубины спуска кондуктора в скважинах, вскрывающих несколько нефтегазоводонасыщенных пластов

Особенности выбора глубины спуска кондуктора в скважинах, вскрывающих несколько нефтегазоводонасыщенных пластов

Casing setting depth and design of production well in water-dominated geothermal system with 330 °C reservoir temperature

Casing, with its two main elements: casing setting depth and casing design, is one of well barrier elements playing a significant role for geothermal well integrity. All of the internal and external loads experienced by the casing from its installation into the well until the end phase of well, called plug and abandonment, have to be calculated precisely. Moreover, the casing must be able to withstand the geothermal environment: high-temperature, high-strength rock, highly-fractured formation, corrosive fluid, and under-saturated pressure. Therefore, the casing specification can be properly determined based on the technical and economic considerations to achieve a high quality of well integrity and endurance starting from drilling and completion, production, maintenance (well intervention, and workover), conversion into an injection well or vice-versa, and plug and abandon (P&A).This research study discussed the production well HCE29 in Dieng Field, Indonesia, characterized by a water-dominated geothermal system with temperature of up to 330 °C and pressure of up to 19.4 MPa. After the well was drilled and completed, the casing failure was identified. This study consisted of analysis and re-calculation of this well at the phases of drilling, completion, production, and maintenance to improve the casing setting depth and design method. The results show that the casing failure occurred in this well. In addition, this study improved the Philippines’ method used for re-calculation of casing setting depth and the casing design evaluation method.

Pre-drill pore pressure prediction and safe well design on the top of Tulamura anticline, Tripura, India: a comparative study

The Tulamura anticline falls in the state Tripura, Northeast India. The anticline is extended up to neighbour country Bangladesh. The region is characterized by huge anticlines, normal faults and abnormally pressured formations which causes a wide margin of uncertainties in wildcat well planning and design. These geological complexities of Tulamura anticline make the drilling engineers more challenging. Therefore, a proper well design is essential in such a region to prevent blowout. Drilling engineer requires to maintain wellbore pressure between the pore pressure and fracture pressure to reduce the possibility of a kick and a formation damage. Pore pressure plays an important role to design a safe and economical well in such a high pressure and temperature reservoir. For wildcat drilling, only seismic data are available in the study area. There are various methods to predict pore pressure from seismic velocity data. Modified Eaton’s method is widely used for the pore pressure prediction from seismic data in terms of the velocity ratio. Modified Eaton’s equations may cause an error by manual selection of compaction trend line which is used to find normal compaction velocity. The main objectives of this study are to develop a new method to predict pore pressure and safe well design on the top of Tulamura anticline in terms of pore pressure. The new method is validated by a well-known method, modified Eaton’s method, and RFT pressure data from offset wells. An excellent match with pore pressures estimated from RFT pressure data and predicted by new model along with modified Eaton’s method is observed in this research work. The efficiency and accuracy level of the hybrid model is more as compared to other methods as it does not require compaction velocity data; thus, an error caused by manual compaction trend can be eliminated. Pore pressure predicted by new method indicates result up to the 6000 m, which is up to the basement rock. The predicted pore pressures by new method are used as an input to calculate the fracture pressure by Hubbert and Willis method, Mathews and Killy method and modified Eaton’s method. Equivalent mud weight selection is carried out using median line principle with additional 0.3 ppg, 0.3 ppg and 0.2 ppg of swab pressure, surge pressure and safety factor, respectively, for calculation of all casing pipes. Casing setting depths are selected based on pore pressure gradient, fracture pressure gradient and mud weight using graphical method. Here, four types of casing setting depths are selected: conductor, surface, intermediate and production casings at 100 ft, 6050 ft, 15500 ft and 18,500 ft, respectively, by new methods, but the casing setting depths for intermediate are at 13500 ft in the case of modified Eaton’s method. The casing policy is selected based on burst pressure, collapse pressure and tension load. For each casing, kick tolerance in bbl is determined from kick tolerance graph to prevent the blowout. Finally, comparative safe and economical wells are designed on the top of Tulamura anticline along with target depth selection, casing setting depth selection, casing policy selection and kick tolerance in consideration of collapse pressure, burst pressure and tension load which gives a clear picture of well planning on the top of anticline in pore pressure point of view.

Application of specific energy for lithology identification

The previous applications of specific energy to drilling operations have focused mainly on drilling optimization and identification of inefficient drilling conditions. Recent advances in specific energy extend its applications to overpressure detection and pore pressure prediction. In this paper, an attempt is made to further extend the application of specific energy to real-time identification of subsurface lithology. The concept is based on the principle that the total energy required to break and remove a unit volume of rock is a function of lithology. The proposed methodology is tested using a recently drilled exploratory gas well in the tertiary deltaic system of the Niger Delta basin. In general, an excellent agreement is observed in trend between the traditional lithology identifiers (gamma ray and sonic velocity ratio) and the total energy consumed in breaking and removing the penetrated rocks. Unlike the logging while drilling (LWD) technique commonly employed in the industry (including the application of near bit sensors placed few feet behind the bit), the proposed methodology can provide a reliable means of picking formation tops and identifying subsurface lithology at the bit with no extra cost since drilling parameters are routinely recorded at the wellsite during the drilling of a well. The proposed methodology will assist the drilling engineers and geologists in determining the casing setting depths and coring points without having to drill too deep into the formation of interest.

Application of risk analysis in drilling well problems and operations- field case study

The objective of this paper is to present specific drilling problems and their solutions, and then apply risk analysis for them. Drilling data for actual drilled wells and performing the risk analysis resulted in medium risk for the most operations done before starting the drilling process. Drilling well operations showed a various risky levels for operations. Formation problems that resulted from a constantly formation /fracture pressures curves may sometimes lead to not being able to select the casing setting depth CSD, and use high rate of penetration ROP without logging may provide a good results. The application of this method resulted in a proper selection of CSD for two drilling wells (I) and (II). In addition, the treatment of a large layer of shale formation X2 for well (I) was done by using common methods to prevent shale problems but these methods will add another 5-6 days to the number of drilling days. However, the proposed high ROP method, without logging, and with quick cementing and casing operations is almost perfect and leads in reducing the drilling hole days by 5-6 days for well (I), and that’s why the final drilling hole days will be 59 days instead of 65 days. Another real drilling well case which is suffering from a lot of well problems was controlled using suitable methods and the required mud additives to all geological sections safely drilled.

Application of Artificial Intelligence Techniques to Estimate the Static Poisson's Ratio Based on Wireline Log Data

Static Poisson's ratio (νstatic) is a key factor in determine the in-situ stresses in the reservoir section. νstatic is used to calculate the minimum horizontal stress which will affect the design of the optimum mud widow and the density of cement slurry while drilling. In addition, it also affects the design of the casing setting depth. νstatic is very important for field development and the incorrect estimation of it may lead to heavy investment decisions. νstatic can be measured in the lab using a real reservoir cores. The laboratory measurements of νstatic will take long time and also will increase the overall cost. The goal of this study is to develop accurate models for predicting νstatic for carbonate reservoirs based on wireline log data using artificial intelligence (AI) techniques. More than 610 core and log data points from carbonate reservoirs were used to train and validate the AI models. The more accurate AI model will be used to generate a new correlation for calculating the νstatic. The developed artificial neural network (ANN) model yielded more accurate results for estimating νstatic based on log data; sonic travel times and bulk density compared to adaptive neuro fuzzy inference system (ANFIS) and support vector machine (SVM) methods. The developed empirical equation for νstatic gave a coefficient of determination (R2) of 0.97 and an average absolute percentage error (AAPE) of 1.13%. The developed technique will help geomechanical engineers to estimate a complete trend of νstatic without the need for coring and laboratory work and hence will reduce the overall cost of the well.

Wiper Trips Effect on Wellbore Instability Using Net Rising Velocity Methods

Background:This paper discusses the wiper trip effects on well instability in shale formations.Objectives:Problematic shale interval sections have been studied for the time spent on the wiper trip operations. Lifting efficiency and well wall instability change with the time analyzed. Detailed drilling operation, formation heterogeneity, rheological and filtration characteristics of polymer water-based mud are discussed. Physical and chemical properties of the drilled formation and drilling fluid are also studied.Materials and Methods:Wiper trips are analyzed using a typical drawing program to find the relations between the most controllable parameters. For that, two calculation models have been implemented to find the net rising cutting particles velocity in the annular. The relation between the net rising velocity and wiper trips is analyzed. Laboratory works have been done to support the findings of field work.Results:Strong relations have been found between the wiper trip impacts and lithology types of the penetrated shale.Conclusion:A modified drilling program is proposed in relation to changes in casing setting depth and drilling fluid properties that make the operations more efficient in cost and time.

FSQGA based 3D complexity wellbore trajectory optimization

Determination of the trajectory of a complex wellbore is very challenging due to the variety of possible well types, as well as the numerous complicated drilling variables and constraints. The well type could be directional wells, cluster wells, horizontal wells, extended reach wells, redrilling wells, and complex structure wells, etc. The drilling variables and constraints include wellbore length, inclination hold angles, azimuth angles, dogleg severity, true vertical depths, lateral length, casing setting depths, and true vertical depth. In this paper, we propose and develop an improved computational model based on Fibonacci sequence to adjust the quantum rotation step in quantum genetic algorithm for achieving cost-efficient complex wellbore trajectories. By using Fibonacci sequence based quantum genetic algorithm (FSQGA) in a complex searching problem, we can find high-quality globally optimal solutions with high speed through a parallel process. The simulation results show that FSQGA can significantly reduce computation complexity, and reach minimum objection values faster. Meanwhile, minimization of the true measurement depth of complex wellbore trajectory in actual gas-oil field shows that the drilling cost can be reduced up to 4.65%. We believe this new algorithm has the potential to improve drilling efficiency, to reduce the drilling time and drilling cost in real-time wellbore trajectory control.

Blowout Prevention and Relief-Well Planning for the Wheatstone Big-Bore Gas-Well Project

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 174890, “Blowout Prevention and Relief-Well Planning for the Wheatstone Big-Bore Gas-Well Project,” by Eric R. Upchurch, SPE, Sam Falkner, Andrew House, SPE, Chinh Nguyen, SPE, and Ken Russell, Chevron Australia, prepared for the 2015 SPE Annual Technical Conference and Exhibition, Houston, 28–30 September. The paper has not been peer reviewed. The offshore Wheatstone project in Western Australia uses subsea big-bore gas wells as the preferred method of producing the field. Each of the highly productive wells represents a source of gas that, if accidently allowed to flow unhindered, could present an uncommonly difficult well-control challenge. This paper details the engineering and operational planning performed to ensure that no uncontrolled hydrocarbon releases occur during the execution of the subsea big-bore gas wells and that, if a blowout were to occur, the response to such an event would be sufficient and robust. Introduction The Wheatstone high-rate gas-well design, with its 9⅝-in. production conduit, represents the company’s initial attempt at implementing such a well. Because the design team’s combined engineering and execution experience included neither big-bore wells nor reservoirs of Wheatstone’s productive magnitude, well-control expectations were limited to anticipating needing only a single relief well in the event of a blowout. However, upon receipt of dynamic-kill simulations performed by consulting experts in that field, a new reality became obvious. That is, the combination of a large wellbore connected to the multidarcy Wheatstone gas reservoir has the potential to produce at more than 1 Bscf/D if flow is unconstrained; in some scenarios, this could require the use of up to four relief wells simultaneously injecting 15-lbm/gal drilling fluid to regain control. Analyses suggest that it is improbable that a dynamic kill at Wheatstone can be performed successfully using only a single relief well, given the large diameter of the production wellbore. Therefore, the well-control risk of drilling a Wheatstone well was mitigated not by limiting its productive capacity (i.e., reducing the well diameter) but by (1) optimizing casing-setting depths to minimize the number of required relief wells, (2) designing the well to be completely pressure competent, even if it were totally filled with gas, and (3) formulating a blowout-response plan that is reflective of the complexities of executing a two-well dynamic kill on any of the nine foundation wells drilled at Wheatstone.

A new approaching method to estimate fracture gradient by correcting Matthew–Kelly and Eaton's stress ratio

Abstract Fracture pressure is one of the most important parameters in wellbore stability. Fracture pressure shows the ability of rock to hold vertical stress before starts to fracture. The application of fracture gradient (FG) affects the well design, such as mud weight profile, casing setting depth, and cementing operation. Fracture gradient could be determined directly by using leak-off test (LOT) and formation integrity test (FIT), and calculation from logging data. There have been a lot of studies in predicting fracture gradient after the fundamental theory of fracture pressure was developed by Hubbert and Willis in 1957. However, most of those studies were performed without considering the geological characteristic, such as precipitation environment, geology structure, and stratigraphy. A new methodology to predict fracture pressure from former calculations, Matthew–Kelly and Eaton, is proposed. The methodology characterized the formation lithology from Poisson's ratio and stress ratio value which is corrected and analyzed by two correcting constants, a and b. As the result, a new value of Poisson's and stress ratio of the formation was generated and the accuracy of fracture gradient was improved. In addition, the flexibility of this methodology indicates that this methodology could be applied in various drilling area.

Dynamic casing shoe while drilling: A smart drilling concept for future monobore technologies

The design process of a casing program involves the selection of setting depths, casing sizes and grades of steel that will lead to a safe drilling and completion of a well to withstand all encountered loads during the life of the well. The selection of casing setting depth is a very important task in preparing the well plan. Many aspects, such as lithology, over pressured formations, shallow gases, lost circulation and troublesome zones, directional well profiles and regulations must be considered in this selection.The development of new materials (i.e. expandables) and new technologies (casing drilling) as well as future concept like monobore well technology has created the need of new casing shoe calculation methodologies.The proposed concept to dynamically estimate the casing shoe depth while drilling is based on real time data and intensive geo-modeling pre-processing. The concept will start on paper with the classical casing shoe setting depth estimation which is used to identify the critical zones after which the dynamic model is applied and simulated. If positive simulation results are obtained, then the drilling process can be started. The new model can predict while drilling the position of the next casing shoe, taking into consideration measurements while drilling like pore pressure or formation properties. However, the success of this concept is strongly linked to modern or future technologies of monobore.