Efficient Well Intervention Eliminated Liner and Tie Back with Efficient Single Casing Expediting Well Delivery

Verkhnechonskoe oil field is situated in Eastern Siberia, Russia. This field is quite unique due to low formation temperatures –the bottom hole static temperature does not exceed 13 degC. This low temperature environment together with low formation fracture gradient present unique challenges for cementing operation. Conventional lightweight system extended by sodium silicate does not meet client well acceptance criteria – no sustained casing pressure (SCP) and successful annular space pressure test due to delayed compressive strength development and relatively high permeability of set cement stone. Failure to meet those criteria’s result in remedial cementing operations and delay of putting wells in production. To overcome this challenge new lightweight cement system based on optimized particles size distribution is successfully introduced for primary cementing of production casing on Verkhnechonskoe field. Implementation of the novel lightweight cement system with high solid volume fraction has allowed client to overcome highlighted issues. Rapid compressive strength development also helped in reduction of well construction time due to shorter wait-on-cement period. This paper outlines an approach based on the usage of optimized particles size distribution lightweight cement system in low temperature environment included three steps of cementing operation: design of cement system, implementation and evaluation results.

Replicating downhole conditions using real-time software helps reduce nonproductive time. Hydraulic outputs trend against sensor outputs, enabling event detection. Using real-time fluid properties with fluid tracking hydraulic software helps improve predictions for comparison, enabling faster and more reliable detection of downhole conditions. Two instances of real-time hydraulics simulators capable of tracking property changes of fluid and the positions of discrete fluid volumes within the wellbore were used. One simulator was used with a real-time fluid properties apparatus that provided full six-speed rheology and fluid density in real time. The second simulator used fluid updates provided by the mud engineer on location. The calculated equivalent circulating density (ECD) and predicted standpipe pressure (SPP) from the hydraulics software was compared to actual pressure while drilling (PWD) and measured SPP sensor outputs. The real-time fluid apparatus provided real-time rheology and density values consistently while drilling the section, and data was provided directly to the hydraulics simulator. Comparing ECD predictions with and without the real-time fluid properties made it possible to identify any improvements achieved using such equipment. Although both sets of data showed that the hydraulics simulator was highly accurate, using real-time fluid inputs enabled ECD predictions to trend considerably closer to the PWD measurements. The capability of tracking the predicted ECD against actual sensor outputs enables users to quickly determine deviations in sensor outputs associated with downhole conditions and to observe deviations occurring as a result of inconsistencies within the fluid system. Data presented in this paper are taken from some of the first global deployments of real-time fluid properties measurement equipment used in conjunction with real-time hydraulics software.

Cementing gas wells in coalbed methane (CBM) formations can present a cement-circulation challenge because the coal formations tend to have low fracture gradients and break down under the hydrostatic pressure of the cement column. The use of conventional lightweight cement slurries and/or foam cement significantly increases the prospect of maintaining circulation throughout cement placement. However, wells with exceedingly low fracture gradients can suffer either partial or complete loss of circulation during cement placement even with lightweight slurries. Both conventional lightweight cement slurries and foam cements have restrictions. Conventional lightweight cement systems use low-density materials (i.e. hollow spheres, gilsonite) and high water-to-cement ratios as a means of reducing the equivalent circulating density (ECD). The lightweight materials and high water requirements detract from the compressive strength of the cement, thereby limiting ultra-low densities while achieving adequate compressive strength. For foamed cement, the gas-to-slurry ratio should stay within a specific range to help ensure optimal cement properties; otherwise, the set cement could become permeable. This requirement has led to the hybridization of two systems to create an effective cementing solution. By combining the two systems, the best attributes of both can be captured. Starting with a lightweight cement system provides a low base-slurry density that allows the gas to be added to lower the density further while maintaining the compressive strength and foam stability. This paper discusses an operator's challenge and the use of the above solution to cement wells in the Western Canada Sedimentary Basin (WCSB) across CBM formations.

World's energy demand is on upsurge and Oil & Gas industry has been directed towards the exploitation of deepwater oil and gas resources. To make this operation successful petroleum industry is continuously demanding new innovative drilling technology that can be easily implemented. One of the constraints that hinders the deepwater exploration is its continuously shrinking narrow window between pore pressure and fracture pressure that further limits the reliability of old conventional riser drilling technique.Dual gradient drilling (DGD) is a managed pressure drilling that involves use of two different annular fluids for drilling a prospect providing a favorable annular pressure profile and simpler, safer & economical well design.In any of the rotary drilling operation, drilling hydraulics is the most complicated and least understood drilling variable as it involves complex relationship between drilling fluid, drill bit and formation. Riserless drilling, one of the type of DGD, eliminates the use of marine riser (u-tube is imbalance) and involves use of an additional subsea mud pump at seabed which, supplements to the complication for hydraulics computation as compared to conventional drilling.In drilling HPHT deepwater wells, drilling fluid is constantly exposed to its own column pressure and formations geothermal gradient which subsequently affects the mud rheology and density. These altered rheological parameters leads to inadequate hole cleaning and lowers the drilling efficiency. High temperature in the wellbore cause's fluid expansion and high pressure causes fluid compression and these changes get extremely severe as water depth and drilling depth increases. Hence it becomes necessary to consider the HPHT effects on Equivalent Circulating Density (ECD) and to correct & optimize the hydraulic program to ensure the best utilization of the hydraulic energy for effective hole cleaning.This paper presents a detailed study of Well hydraulics for riserless drilling considering the HPHT effect on Equivalent Circulating Density and its optimization so as to ensure riserless drilling operation is conducted in safe and effective manner. Also the paper is concluded with some recommendations on operational and design strategies.

Investigating the thermal properties of single-grade engine oil (SAE 50) with the simultaneous addition of MWCNT and CuO nanoparticles

In this study, the preparation of nanofluid (NF) is performed by the two-stage method by dispersing nanoparticles (NP) into the base fluid (BF). Hybrid nanofluids (HNFs) were prepared in the solid volume fractions (SVFs) of SVF = 0.1, 0.2, 0.3, 0.4 and 0.5% and mono nanofluids (MNFs) were made in SVF = 0.1 and 0.3%. After ensuring stability, the thermal conductivity (TC) of HNFs and MNFs is measured by the hot wire method at a temperature range of T = 20–60 °C. The results indicate that the TC (For HNFs and MNFs) increases as the temperature increases. Increasing the SVF also increases TC, which is more evident in the higher SVFs. According to the obtained results, the highest increase in the TC is related to the MWCNT-CuO-cerium oxide/water HNF in SVF = 0.5% and T = 60 °C, which is a 26.7% increase compared to BF. In SVF = 0.3%, the MNFs containing MWCNTs NPs have a better performance than the HNFs. Compared to the results with the relationship of Lu-Lin, it was found that the temperature is critical in increasing the TC. There are no temperature parameters in the Lu-Lin model, therefore there is a difference between the laboratory results and the Lu-Lin model results. Finally, based on experimental data, a mathematical relationship between temperature and SVF was proposed to predict the TC for HNF water/cerium oxide-CuO-MWCNT. Comparing the experimental data to the outputs of the proposed relationship shows that this relationship is accurate.

A major operator drilling in the Krishna-Godavari (KG) basin faced challenges attributed to tight tolerance and severe losses while running-in casing in deepwater conditions. The operator initially spent up to five days of rig time filling the casing conventionally and reducing running speeds to reach the planned depth. To help mitigate severe losses and high surge pressure caused by tight tolerance in the wellbore, the operator had to reduce the running speed and use high quantities of lost-circulation material (LCM), which caused premature conversion of float equipment from autofill mode to conventional mode (closed-ended pipe) midway, resulting in longer casing run-in time. Surge and swab analysis was conducted to validate equivalent circulating density (ECD) reduction during the casing run and derive a program of operation to safely optimize the casing run. The surge reduction float equipment package, comprised of a retained flapper valve and ball activation system, allowed the casing to autofill through large flow by areas, tolerant to the LCM in the well, while maintaining compatibility with the subsurface release plug system necessary for deepwater operations. The system allowed for midway circulation, as necessary, to help ensure the fluid level could be maintained during the casing run. The surge reduction equipment set was the first of its kind and consisted of three flapper valves distributed between the float collar and float shoe to provide the necessary redundancy to combat issues with the floats not holding because of the harsh conditions of the operation. It allowed casing to be run at optimum speed and remain within the pore pressure and fracture gradient window. A single deactivation ball installed in the float collar helped ensure the conversion of all valves in both the collar and shoe at the set flow rate, once reaching the planned casing shoe depth. This system combined with high LCM compatible subsurface plug sets not only induced zero losses while performing run in hole (RIH) casing operations (enabling 400% increased casing running speed), it also ensured consistent shoe track integrity with no float valve failure and no wet shoe; this saved several days of deepwater rig time for the operator. The first ever successful deployment of surge reduction float equipment with a subsurface release plug system in India is discussed, which reduced casing run-in time by up to 22 hours.

To maximize reservoir drainage and production volumes from a field in the United Arab Emirates (UAE), extremely long horizontal sections are necessary through the producing interval. Extended reach drilling (ERD) imposes significant requirements on the drilling operation and complicates the running of the production liner because of the long horizontal displacement. This paper details the design and field execution of an organophillic clay-free invert emulsion fluid (OCF-IEF) that met these ERD requirements and facilitated the longest liner run in the world. Successfully delivering a gauge wellbore with >20,442 ft of open hole at 90° inclination, followed by running and setting a production liner at target depth (TD), was not deemed achievable using a conventional invert emulsion fluid (IEF). A correctly designed fluid system was necessary to deliver success. The necessary fluid properties included a low rheology profile to minimize equivalent circulating density (ECD) to keep within the fracture gradient, long-term fluid stability, minimal formation damage risk, and low solids content to help minimize friction. A calcium-bromide brine-based low-solids OCF IEF was selected to meet these requirements. Through the use of this OCF-IEF system, the operator was able to achieve the well objectives, drilling one of the longest wells in the UAE, reaching a TD of 29,075 ft, including a record-breaking 20,442-ft openhole. The 8 1/2-in. reservoir section was drilled in 37 days, with only three trips necessary to change the bottomhole assembly (BHA). The average rate of penetration (ROP) varied between 70 to 100 ft/hr. The maximum ECD observed did not exceed the fracture gradient at any stage. Consequently, no downhole losses were experienced during the drilling phase. The engineered OCF-IEF achieved a low rheology profile, which minimized the contribution to annular pressure losses. The low rheology profile and low solids content in the IEF resulted in excellent fluid stability with no weighting material SAG. No losses were observed while running the liner, and no indications of tight spots were observed. Friction factors were low (between 0.15 and 0.25), and this facilitated the liner to be run without any issues. Total days on the well were 30 less than planned, which significantly saved both costs and rig time for the operator. The organophillic clays and organophillic lignites are replaced with various organic polymers to achieve different fluid behaviours (Strand et al. 2016). The novel polymer chemistry of this OCF-IEF together with a low solids content (attributed to using calcium-bromide base brine) resulted in desirable fluid properties that allowed the operator to extend limits, reach new depths, and break records to maximize production and increase revenue.

Epoxy resin applications in oil and gas wells have significantly increased for remediation and sustained casing pressure mitigation because of its solids-free nature and excellent thermomechanical/bonding properties when used either as a single component or as a resin/cement-enhanced composite. Therefore, it is imperative to assess the formation and degradation of structures in cured epoxy resin at downhole temperatures, particularly because hydrocarbon production requires long-term wellbore integrity. Differential scanning calorimetry was used to determine the glass transition temperature ( $$T_{\mathrm{g}}$$ ) of the proposed resin system, and thermogravimetric analysis (TGA) was used to characterize the thermal degradation response by monitoring the resin specimens’ mass loss over time under controlled temperature ranging from 300 to $$680\,{^{\circ }}\hbox {F}$$ at atmospheric pressure. The thermal kinetic response based on TGA was then modeled using the Arrhenius equation to predict the resin lifetime under expected wellbore conditions. This work also presents a case study in which an epoxy resin–cement composite is used as an annular barricade to help prevent and reduce sustained casing pressure. The resin–cement composite was placed in the annular section between the 18 5/8- and 13 3/8-in. casing sections as a chemical packer tailored to improve bonding to steel pipe, along with optimizing its mechanical response to cyclic downhole loads, which resulted in no up-to-date sustained casing pressure. For a resin system subjected to downhole temperatures of $$263\,{^{\circ }}\hbox {F}$$ , the model predicts that reaching 10% mass loss by thermal degradation can take more than 160 years, which is beyond the operational life of the wells where the system is evaluated. This indicates that the investigated resin system provides long-term dependability that ultimately results in reduction of intervention/remediation costs, along with production maximization. Additionally, the resin mechanical properties were evaluated at different temperatures to assess their response to expected thermal loading, which resulted in competent barriers that can withstand the cyclic loads generated by continuous wellbore operations. Furthermore, cement bond log results further support the optimum annular integrity attained when utilizing a cement–resin composite as chemical packer for enhanced isolation and annular pressure buildup mitigation.

The plastic forming of magnesium alloy is difficult, but the semi-solid material forming is a good method solved this problem. The mechanical model of the semi-solid materials was treated as that of the continuous porous materials in the high solid volume fraction. The upper bound theory applied for semi-solid metal plastic forming process was developed. The velocity discontinuities exist not only in the tangential component but also in normal component for the kinematically admissible displacement increment filed. The latter one was responsible for a change in solid volume fraction when the material passes the discontinuity. An upper bound analytical model and theoretical method of plastic forming process for semi-solid material has been proposed. The calculating formulas of deformed power were derived. It is theoretical basement to apply further for the practice technology analysis such as the plastic forming of magnesium alloy.

A three-dimensional multilayer shallow water approach to study polydisperse sedimentation and sediment transport in a viscous fluid is presented. The fluid is assumed be loaded with finely dispersed solid particles that belong to a finite number of species that differ in density and size. The model formulation allows one to recover the global mass and linear momentum balance laws of the mixture. The model incorporates compressibility of the sediment and viscosity of the mixture through a viscous stress tensor. As a consequence of a dimensional analysis applied to the global mass conservation and linear momentum balance equations, the horizontal components of the compression term and the horizontal terms of the viscous stress tensor may be neglected. This results in a final model that is vertically consistent with the classical one-dimensional vertical model. Numerical simulations illustrate the coupled solids volume fraction and flow fields in various scenarios and the effect of the compressibility and viscosity terms. Various bottom topographies give rise to recirculation of the fluid and high solids volume fractions on the bottom.

Optimization of response function on hydromagnetic buoyancy-driven rotating flow considering particle diameter and interfacial layer effects: Homotopy and sensitivity analysis

This report presents the three-dimensional electromagnetohydrodynamic flow of a zinc-oxide–water nanofluid past a bidirectional Riga plate with velocity slips and thermal and mass convection conditions. The Cattaneo–Christov heat and mas flux model, thermal radiation, chemical reaction and activation energy are considered to analyze the flow problem. The volume fraction of the ZnO nanoparticles is taken 6% in this analysis. An appropriate set of similarity variables is used to transform the partial differential equations into ordinary differential equations. During this process, some parameters are found and influences of these factors on the flow profiles are shown and discussed in detail. A numerical technique called NDSolve is considered for the solution of the nanofluid flow problem. The results showed that higher solid volume fraction and slip parameter have reduced velocities profiles and the increasing solid volume fraction and thermal Biot number have increased the temperature profile. Additionally, the concentration Biot number has increased the concentration profile. The modified Hartmann number has significantly increased the velocity profile. Dual impacts in velocity profiles along primary and secondary direction has been observed due to stretching ratio parameter. A comparison of current results has been carried with a fine agreement amongst current and established results.

The impacts of the solid volume fraction Vs and particle size dp on the total and local gas holdups in gas‐liquid‐solid bubble columns under different flow regimes were investigated. The flow regimes discussed were the discrete bubble regime (DBR), transition regime (TR), bubble coalescence regime (BCR), and strong turbulent regime (STR). The results demonstrated that the bed average gas holdup εg decreased with higher solid volume fraction in DBR, TR, and BCR. The increment of the solid volume fraction promoted bubble coalescence and also can enhance the particle effect on the average gas holdup. The εg changed slightly when shifting the Vs or dp in STR. A new correlation for εg was developed considering the particle properties and the flow regimes studied.

The flow behavior of native corn and potato starch granule suspensions prepared in a concentrated sucrose solution has been investigated. Measurements were performed using a rotational rheometer with a concentric cylinder geometry. Starch suspensions were dilute to semi-concentrated (1 % to 25 % by volume). Shear and dynamic viscosity were measured by shear flow and dynamic oscillatory testing at 20, 50 and 80 °C. The starch suspensions exhibited essentially Newtonian behavior at all solid contents, although at higher solid volume fractions there was evidence of slight shear thickening. The relative viscosity of suspensions increased with increasing starch granule content, and the data conformed well to Maron-Pierce’s equation. An increase in maximum packing fraction and gravitational depletion of the starch granules with increasing temperature resulted in lower relative viscosities at higher temperatures. Also, the relative viscosities of potato starch granule suspensions with bigger, more oval and anisometric particles were lower than those of corn starch suspensions where granules were closer to sphericity but were angular in shape. Oscillatory shear testing results showed the presence of viscoelastic properties at intermediate solid volume fractions at low frequencies; in addition, the relative shear viscosity was higher than the relative dynamic viscosity, probably due to the formation of shear-induced structures during the shear flow test.