bluuebunny/crossref_metadata_2025 huggingface dataset:
Boost Capacity of Velocity String Completions in Sultanate of Oman by Including Sliding Side Door
Authors: Hinai Khalid , Veeken Kees , Janusz Norbert , Mabsali Laila , Naabi Hajer , Al-Ruheili Sharifa , Ruzaiqi Musallam
Published: November 2017

Velocity strings are routinely installed to remediate liquid loading of gas wells. However, besides restoring stable production, velocity strings also reduce well capacity, easily by up to 50%. In PDO, a sliding side door (SSD) was introduced as part of the velocity string completion to reduce the loss of capacity by facilitating additional gas flow via the new annulus created between velocity string and original tubing. This paper documents different field cases that demonstrate how the SSD is manipulated to maximize well capacity, which in some cases was doubled for more than 1 year. The paper also presents modelling of gas production via velocity string, annulus or both (concurrent). Commercial software was not able to accurately predict the instability of concurrent gas production.
Innovative Use of Drones Improves Safety on Asset Integrity
Authors: Kumar V. Sivaraj
Published: November 2017

Objective/Scope

The objective is to find a safer and efficient method for carrying out inspection on the jack up legs and inside tanks supporting ADNOC and NDC pillars.

Method/Procedures

Offshore rigs require to be surveyed every year with the intensity of examination increasing between annual, intermediate and five-yearly frequencies. Examination includes numerous challenging compartments and spaces. These could be: Seawater tanks (normally closed and sealed), rig legs (hundred or more feet tall) underside of helidecks (over water). NDC introduced use of drones for tanks surveys thus mitigating all risks and introducing commercial efficiency as a lot of preparatory costs were avoided and the rig outage time considerably reduced.

Result/Conclusion

NDC decided to pioneer the region's first drone inspection of tanks and hull structures for offshore units amongst the drilling contractors thus demonstrating how the use of this technology can be applied to greatly improve safety, eliminate risks, increase efficiency and reduce costs. In a pilot trial of the concept the company demonstrated how a typical week long inspection program can be completed in a single day – a cost and efficiency improvement of almost 700%. Risks include lack of oxygen, fall from heights and injuries from obstructions. Of course experienced industry staff takes a lot of precautions before attempting such tasks. In fact companies have developed "Golden Rules" that govern activities inside confined spaces.

Novel

Scaffolding needed to be erected inside tanks using specialized crews at considerable cost. Tanks needed to be ventilated in advance of the tanks entry. Work needed to be done at heights with staff working on scaffolding with limited lighting. Rig time was being lost when it was brought to the jetty for surveys for ensuring safe access before surveys could be carried out.
Microemulsion Additive to Mitigate Impacts of Acid Flow Back
Authors: Morales R. , Diaz C.
Published: November 2017

Interaction between organic/inorganic acid and crude oil, especially in the presence of free iron, might result in asphaltene precipitation and acid sludge formation, as well as fluid separation problems at the surface facility. These problems cause a decrease of well productivity and increase d operational cost. To mitigate the potential damage associated with acid stimulation to improve its performance, the following aspects need to be considered.

Methods, Procedures, Process

To identify the appropriate stimulation additives that ensure the performance of the acid job and prevent rigid film emulsion, a proper sludge evaluation is needed. The stimulation additives need to be miscible and compatible with different acid packages, need to have good affinity with the oil and water phases, high tolerance to the presence of free iron, and low contact angle to water-wet the formation for production improvement.

This paper addresses the required properties of stimulation additives in formulations for wells that produce low API gravity crude oil (less than 15 API), have downhole temperatures up to 150°C, and contain approximately 5000 ppm of free iron.

An extensive laboratory performance study including produced fluids compatibility, acid sludge tests at different oil and acid ratios, as well as iron content, were performed to identify suitable acid additives to minimize acid flow back problems in heavy oil fields. The impact of the acid flow back fluids with acid additives on fluid separation at surface facility conditions was also evaluated.

Identifying the most suitable and effective additives to prevent the acid sludge formation during the acid jobs and minimize the side effect of acid jobs on surface facilities, is presented in this paper, as well as the effect of microemulsion on this application and its effectiveness.

It is expected that results of this study will help the industry to minimize the downhole and surface problems associated with flow back in acid jobs.
Taking Drilling Operations Optimization to New Heights
Authors: Moustafa Islam khaled , Hammadi Majid Al , Rheaume Gregory , Ali Salim Al , Jaorawala Ammar , Mefleh Issam Rezek , Helali Osama Al , Salam Mohamed Abdel , Akl Bassam
Published: November 2017

Field Background

In Aug. 2015, Umm Lulu drilling team drilled and completed well014 as a first linerless design by setting the 9 5/8" casing in Thamama-I formation and drilling an 8 ½" section till TD, relying on swell packer for zonal isolation.

Post evaluation of UL-14 design found cross flow between Thamama-I formation and Thamama-II target reservoir.

The drilling division developed another design by extending drilling the 12 ¼" hole till Thamama-I A base to isolate Thamama-I with cement after running the 9 5/8" casing and drilling 8 ½" hole till section TD. This scenario was not possible to execute due to the unavailability of completion equipment (4 ½" × 8 ½" swell packer).

The drilling division thought out of the box to drill 6" hole directly from 9 5/8 casing to address the equipment availability constraint. This option was pursued after thorough evaluation of all potential challenges.

In April 2017, well018, which was a first revised design, was drilled and completed successfully 10 days ahead of plan, saving $2.00M.

In June 2017, well020 was delivered with the best jack up 10k duration in ADMA-OPCO (31.5 days) and the best single oil producer with lower completion duration of 56 days, saving more than 15 days and $3.2M.
Changing Perspectives of Cathodic Protection System for Above Ground Storage Tanks
Authors: Hanif Ateeq. Ur-Rehman , Busaeedi A. M.
Published: November 2017

A Cathodic Protection system can provide effective corrosion control against external corrosion threats to above-ground storage tanks; be it related to tank construction materials, coating degradation over operational life span or environmental corrosion caused by tank foundation, soil etc. Traditionally, several different types of anode installation schemes were practiced for current distribution to the tank bottom. These were ‘Horizontal or vertical’ anode installation distributed around the tank periphery or angular drilled anode installation to extend the anodes toward center of the tank bottom. Deep-well anode systems with multiple anodes in a single long bore-hole at relatively remote location were also used to provide common cathodic protection system for multiple tanks in tank farm area. These conventional anode-beds were easy to install, monitor and maintained. For safety and environmental reasons in new storage tank construction, an impermeable plastic membrane is now required to be laid under the tank to contain any corrosion leak if it happens. The use of a membrane beneath the tank bottom as secondary containment and as a means of leak detection thwarts any attempt of conventional anode-bed outside the tank periphery to be effective. The anode-bed and references electrodes or other monitoring systems are therefore installed within the space available between the membrane and the tank bottom during construction of the tank, as retro-fitting of anodes during operational service life would not work because of the inaccessibility below the tank bottom. A robust design of the cathodic protection system for a tank bottom is therefore imperative to ensure intended design life.

This paper briefly discusses the changing perspectives of the cathodic protection system from conventional anode-beds to a grid system showing the detail design approach adopted and highlights the implications of miss-design based on a practical example of a newly constructed 100 meter dia crude oil storage tank with 40 years design life if relevant design considerations are not addressed.
Successful Use of Downhole Camera Technology to Assist Fishing Operation
Authors: Al-Hajri Nasser M. , Al-Quwaisim Hussain A. , Al-Zahrani Rashad M.
Published: November 2017

Fishing operations are complex and time consuming. This is due to the associated uncertainty with the orientation and condition of the tool that requires fishing. In this paper, a case study is presented which demonstrates the usefulness of utilizing downhole camera technology in conjunction with fishing operations. The use of real time camera inspection enabled successful fishing of a challenging plug. In addition, the traditional trial and error approach used in most fishing operations was avoided reducing the operation time and cost.

The paper case study is a high pressure oil producer that has a stuck retrievable plug at 200 ft. The presence of the fish at a shallow depth makes well intervention operations critical from well control perspectives. In such cases, fishing operations must be meticulously designed to account and plan for contingencies should complications arise during fishing. Attempts to fish the plug using normal and heavy duty slickline were not successful. During these fishing attempts, several tools were lost in hole due to the damaged nature of the stuck plug adding to the complexity of the fishing operation.

To address this challenge, a downhole camera with real time data transmission capability was run in the well using coiled tubing to enable viewing the condition and orientation of the lost fishing tools and the stuck plug. The results of the camera inspection runs were instrumental in subsequent fishing tools selection and adjusting the operating procedures. The first camera run revealed the presence of metal objects obstructing proper latch to the fish neck. Following clean-up runs with magnet, the second camera inspection run clearly showed partial damage to the top of fish neck (chipped out metal piece). The rest of the fishneck was found intact.

Given the nature of damage to the top of the fishneck, conventional fishing tool sizes (3 in.) were not able to latch the fish. Accordingly, a smaller fishing tool (1.26 in. spear) was run and latched inside the bottom of the fish neck instead of the damaged top. The 1.26 in. spear run was successful in latching inside the fishneck and in recovering the fish safely. The fishing operation design, job execution, and contingencies will all be discussed in this paper.
Integrated Data Analysis Reveals the Presence of Sealed Fractures in a Large Tight Gas Field
Authors: Zadjali Faris Al , Saroj Vikram Singh , Calvert Stephen , Djermouni Karima , Hattali Ahmed Al , Rawahi Mohamed Al , Noirot Jean-Christophe , Kharusi Dawood Al
Published: November 2017

One of the largest gas fields in the Sultanate of Oman was developed between 2010 and 2016 by drilling 26 vertical wells for commingled production from three deep tight gas sandstone stacked reservoirs. The shallower reservoir is a rich gas condensate reservoir, while the other two contain lean gas fluids.

Over the last few years, the wells performance has been poorer than anticipated. An integrated study was carried out in 2016-2017 to identify the root causes of this under performance and eventually address it in a new field development plan. All subsurface and surface disciplines worked together analyzing available data in order to understand the production behaviour and complex nature of the field.

One of the major findings of the integrated study was the interpreted presence of sub-seismic lineaments corresponding to possible zones of quartz sealed fractures. This was supported by seismic, core, reservoir pressure (MDT) and pressure build up data. The integrated data analysis revealed that these lineaments are having a direct impact on the field performance, as the hydrocarbon in-place volume seen by each well is dependent on the compartments defined by these lineament boundaries. A large set of lineaments were added to the dynamic model after mapping from detailed seismic work. This addition resulted in very good matches of historical production and pressure data. These updates to the reservoir model will ensure a more accurate field forecast and provide a better field development strategy.

This paper will demonstrate that the presence of sealed sub-seismic fractures that may remain undetected can have a substantial impact on the performance of tight gas reservoirs. By identifying these sub-seismic elements and understanding their impact through an integrated approach, field performance can be better forecasted in order to account for the presence of these features.
Resolving Water Saturation Uncertainty in a Thin Oil Rim Reservoir, Using Sigma While Drilling, Case Study from Onshore Abu Dhabi
Authors: Syofyan Syofvas , Latief A. I. , Amoudi M. A. , Al-Arfi S. A. , Al-Shabibi T. A. , Dasgupta Suvodip , Qleibo Meretta , Gzara Kais
Published: November 2017

Objectives

This study focuses on resolving the water saturation (Sw) uncertainty in a small oil rim that consist of thin high-permeability layers (super K). Resistivity-based water saturation techniques suffer from multiple uncertainties including thin layers with distinct capillarity profile, inaccurate resistivity due to high-angle bed effects and unknown Archie parameters. Accurate saturation using alternate methods than resistivity based is critical for the calibration of saturation height model for reserve estimate and to design the perforation program away from the mobile water zone.

Methods

To resolve the issue of accurate Sw, an alternate method of computing saturation from sigma measurements while drilling is being investigated. Data from multiple wells has been analyzed- saturation from sigma being computed and compared to resistivity based saturation. The resulting saturation is benchmarked against other known sources of saturation like core data and cased-hole measurements. The input parameters used to compute the sigma-based saturation were validated by well test and PVT lab data.

Observations

A general assumption for LWD logs is that invasion is so shallow that LWD data acquired during drilling may be sufficient to evaluate uninvaded zone properties However, this premise need to be confirmed by other sources of information, in this case Multi-Depth of Investigation (MDOI) sigma data. It provides valuable insight into the status of formation invasion, at the time of acquiring data and of measurement quality control. In situations where the resistivity data does not suffer from any high-angle bed effects, there is immense value in combining the information from resistivity and sigma. When there are two measurements free from invasion and reading the same volume of rock, this can be used for not only calculating water saturations but also to fine-tune the Archie parameters, which might be of immense value in situations, for use on offset wells with resistivity data only.

Novel Information

Sigma while drilling is another weapon in the arsenal of the petrophysicist and the multi-depth of investigation sigma measurements in a LWD environment contributes a new opportunity to evaluate fluid saturations in reservoirs with unknown or variable Archie parameters.
Automated Well Test Analysis Utilizing Self-Adaptive Differential Evolution Method
Authors: Moussa T. M. , Alloush R. M. , Issaka M. B.
Published: November 2017

Well testing is the analysis of pressure and rate data from a reservoir to estimate the reservoir parameters. It enables monitoring and optimization of reservoir performance, and helps estimating the petrophysical properties of the reservoir. Nonlinear regression was presented to well test analysis more than three decades ago, and rapidly became the typical practice in the industry since then. Despite its popularity, the nonlinear regression technique received limited development, and still has major problems in well test analysis. In nonlinear regression, wrong initial guess of regression parameters could lead to incorrect results; as the regression algorithm might not converge to the exact results when the initial parameters' estimations are far from the actual values. This is mainly due to the convergence of some algorithms, such as Levenberg–Marquardt's algorithm, to a local minimum and missing the global minimum of the objective function.

The objective of this research is to develop a well test analysis technique utilizing Self-adaptive Differential Evolution (SaDE) algorithm, this technique can perform automatic reservoir parameters estimation using the pressure and its derivative responses for different reservoir models. The proposed approach is applied on different reservoir models, namely; radial flow in a radial composite reservoir model and radial flow in a circular homogeneous reservoir model. The performance of the developed method is analyzed and compared with Levenberg–Marquardt's algorithm. Sensitivity analysis is introduced to study the effect of different model parameters such as; wellbore storage, skin, mobility ratio, etc.

The obtained results showed that the developed well test analysis technique, using SaDE optimization algorithm, can be used to estimate the reservoir parameters with higher accuracy compared to Levenberg–Marquardt's algorithm. Unlike Levenberg–Marquardt's algorithm, the introduced well test analysis technique has less dependency on the initial estimate of parameters, and the overall regression performance is significantly enhanced. Furthermore, for automated interpretation in which the model is already known, this method allows the elimination of the initial guess-determination step.

This is the first time SaDE algorithm is implemented and applied to estimate reservoir parameters in well test analysis. Therefore, it is a step forward to, fully automate well test analysis and interpretation, where the need of initial estimate of regression parameters is eliminated. This achievement is not possible using conventional gradient-based algorithms such as Levenberg–Marquardt. Outcomes of this study would help well testing engineers and analysts to have better understanding of reservoir parameters and performance without initial guess-determination step.
A Novel Displacement Mechanism of CO2-Assisted Steam Flooding for Highly Acidic Heavy Oil Reservoir: An Experimental Study
Authors: Li Yi-Bo , Gao Hao , Pu Wan-Fen , Yang Liu , Dong Hong , Zhang Xiang , Wu Runnan , Li Qingzhi
Published: November 2017

The steam injection is an effective way to development heavy oil reservoir. But for the high acidic heavy oil, due to the high amount of naphthenic acid, the steam and heavy oil can easily form W/O emulsion which possesses higher viscosity and lower temperature sensitivity than crude oil and increase the displacement difficulty. The introduction of high pressure carbon dioxide was able to destroy the W/O emulsion structure and decrease the viscosity of formation fluid. In this paper, based on the NS block reservoir condition, the physical simulation experiments were carried to investigated the demulsification of CO2 in the displacement process. The results showed that The high acidic heavy oil of NS block can be formed the W/O emulsion easily during the steam flooding process and the high viscosity of emulsion increased the difficulty of displacement. In the flooding process, the high pressure CO2 possessed the demulsification function for the emulsion and thus the lower viscosity of oil can lead to higher cumulative recovery. The alternative injection measures achieved the highest recovery and appropriate CO2/steam volume ratio is very important to the following flooding. The temperature of steam had the biggest influence on the final recovery. The demulsification effect of high pressure carbon dioxide has never been considered as the mechanism of displacement. For highly acidic heavy oil, if the generated emulsion was able to be demulsification by carbon dioxide during the flooding process, it will become one more advantage for carbon dioxide as the important displacing medium in EOR area.
An Industrial Hygiene Study in Support of a Sustainability Initiative: Clean Air for All
Authors: Simmons R. J. , Rodrigues C. C. , Stephen S. , Al Maflahi M. A. , Yousuf R. Y.
Published: November 2017

This paper presents the results of an industrial hygiene study that confirmed the effectiveness of an active system in reducing the potential for employee, as well as public, exposure to benzene vapor. ADNOC Distribution has introduced an advanced vapor recovery system in some of its petrol stations, which is better known as a Vapor Recovery Unit (VRU) System. This system promises a reduction in the volatile organic compound concentrations in the ambient air in the stations, which are linked with the stations’ operations. These volatile organic compounds may cause health issues for both long and short term exposures. This study is conducted to confirm the validity and the benefits of implementing the VRU system in compared to petrol dispensing without VRU. The project was commissioned on two stations, one that was equipped with a VRU system while the other was not. Air sampling using 3M Organic Vapor Monitors™ (OVM), followed by desorption with carbon disulfide and analysis via GC-FID was conducted during May-June 2016. Sampling was conducted on two employees per 8-hour shift per station over two 24-hour cycles (total of 24 samples). Blank samples (one per shift) were also collected and analyzed with the actual samples. Meteorological data were obtained from Al Bateen Executive Airport during the sampling periods. While all of the results showed benzene exposures that were within UAE regulatory limits, a few samples from the non-VRU-equipped station showed exposures that were above the most stringent international guideline, the NIOSH Recommended Exposure Limit (REL). The data clearly encourage the roll-out of the VRU system in all of ADNOC petrol stations. Results were found to be promising; more than 58% of the samples from the VRU station did not contain any detectible concentrations of benzene, as compared to none of the non-VRU stations’ samples. This validates the purpose of the VRU system and hence, the study confirms the benefits of implementing the system from an HSE perspective, as it assures the Company’s workers a healthier and a safer working environment, and also supports the implementation of self-service petrol stations in the UAE, by reducing public concern about hydrocarbon exposure during petrol dispensing.
Multiple Key Operational Achievements Yield Major Economic Impact as a Result of Successfully Controlling Fluid Losses in Troublesome Zones of Jurassic to Permian Age in Offshore United Arab Emirates
Authors: Habsi Medhat Al , Bijjani Patrick , Dawson Graeme , McCurdy Paul , Anez Marcos , Luyster Mark , Tresco Kim , Dobson James W.
Published: November 2017

Two optimized polymer/borate/salt (PBS) fluid loss systems were recently implemented in two different ADNOC Sole Risk (ASR) wells while drilling different troublesome formations in the Arabian Gulf which are prone to losses. The first well (Well A) was drilled through the fractured Upper Khuff Formation, and the second well (Well B) through porous Arabs and fractured Diyab/Jubaila groups. The application of the PBS systems enabled the rigs to regain circulation and successfully drill to the total planned depth with less non-productive time attributed to curing losses.

The wells involved several different key objectives; however, zonal isolation and logging were critical to both. In addition, the ability to control losses, even at an acceptable rate for one of the wells, allowed the team to proceed with the critical logging program. If not mitigated, losses could have resulted in a well-control situation.

Controlling the losses on Well A allowed the first unimpeded logging suite, including high quality imaging, pressure sampling and avoidance of a liner run. After logging the section, drilling was resumed to the planned section total depth, and the liner was run and cemented successfully.

The application of the PBS system in Well B allowed multiple troublesome formations (Arabs/Diyab/Jubaila/Gulailah/Sudair) to be drilled as one interval and successful isolation of these zones. The losses were completely cured after applying this system in the correct zone. The total planned depth was attained and the casing landed and cemented.

The solution for these loss-circulation challenges when drilling was the development of a faster, as well as flexible, setting and crosslinking PBS system that could effectively bridge and/or adhere to the formation rock. The optimization also included extending thermal stability of the set plug to maintain a workable loss rate at the anticipated elevated temperatures and simulations to ensure the system would agglomerate and adhere to the limestone/dolomite rocks. Pre-planning started nine months prior to drilling these wells. The predicted challenges ranged from managing losses to developing contingencies for total loss of circulation through the above-mentioned formations. Contingency systems were devised using a decision tree and rig instructions were prepared for every wellbore/scenario. The planning process included determination of a pumpable volume that would facilitate spotting this fluid loss system only once.

This paper outlines the successes achieved in curing loss circulation in the 8⅜-inch section of Well A within the Khuff formation and the 12¼-inch section of Well B within the Diyab group formation. These were drilled in ASR Arabian Gulf region as shown in Fig. 1. Figure 1Location of the ASR wells in the Arabian Gulf.
Study on Rising Velocity of Methane Bubble in Deepwater Wellbore During the Shut-In Period
Authors: Li Hao , Sun Baojiang , Gao Yonghai , Guo Yanli , Zhao Xinxin , Wang Jintang , Wang Jin Bo
Published: November 2017

The formation of hydrate membrane on the methane bubble surface could occur in the high pressure & low temperature wellbore during the shut-in period. Using an empirical drag coefficient model to investigate the laws of methane bubble with hydrate membrane rising in drilling mud is important for calculating the well control safety operation cycle time in avoiding typhoon. The drag coefficient for methane bubble with hydrate membrane rising in mud within a wellbore was experimentally investigated using a vertical, cylindrical wellbore with high pressure & low temperature. A high-speed camera was used to obtain the process of methane bubble with Methane hydrate membrane (MHM) rising under 6 MPa & 4 °C. The velocities of bubbles were measured by image processing software. The drag coefficients of different bubbles were calculated and the variation law of drag coefficient with Reynolds number was obtained. A new correlation of drag coefficient for the bubbles covered with hydrate membrane is established. The result of experiment indicated that the rising velocity of methane bubble with hydrate membrane would increase along with the increase of equivalent diameter, while drag coefficient would decrease before increase along with the increase of equivalent diameter. Due to the influence of hydrate membrane, the rising process of methane bubble covered with hydrate membrane would be significantly different from that of pure gas bubble; compared with pure gas bubble, the methane bubble of same diameter would have lower rising velocity. Through the comparison with known correlation of drag coefficient, it is believed that the existing drag coefficient correlations are not applicable to the prediction of drag coefficient of methane bubble covered with hydrate membrane. A new correlation of drag coefficient of rising methane bubble covered with hydrate is established, such correlation has scope of prediction error within ±25%. Considering the influence of hydrate membrane, a new rising velocity model for methane bubble covered with hydrate membrane is established to calculate the drag coefficient.
Intelligent Completion or Well Intervention Robot?
Authors: Correa Nathalia Alves , Barcelos Tadeu Franca , Miura Kazuo , Mendes Jose Ricardo
Published: November 2017

Well interventions represent one of the main operational expenditure (OPEX) in the O&G industry, especially in offshore fields. Historically, high cost of semi submersible rigs or drillships and long time to acomplish them have restricted the offshore well interventions. Based on this, the O&G industry has developed technologies in order to perform offshore well interventions in an economically viable way. Riserless well intervention (RLWI), intelligent completion (IC) and intervention robot (IR) are relatively new technologies and recently gained importance in the O&G industry.

Therefore, this paper details the operations and values of IC, RLWI, and IR technologies. Moreover, we analyze and compare those technologies, confronting them against the known production loss problems that require well intervention.

The objective is indicating which technologies are feasiable for the future well intervention on subsea wells.
cMIST™: Novel, Compact Dehydration System for Reducing Size and Weight
Authors: Thierens Danny , Ramkumar Shwetha
Published: November 2017

The natural gas industry is increasingly pursuing compact and lower weight processing technology to meet the technological and economic demands of offshore, onshore, remote, and challenged gas processing. This paper describes ExxonMobil Upstream Research Company's (EMURC) new inline dehydration and separation technology meant to replace conventional TEG tower and associated separator vessels to meet pipeline dew point specifications. Compact Mass transfer and Inline Separation Technology (cMIST™) achieves this goal with significant reductions in weight, footprint and cost.

The results of a field demonstration completed in February 2016 are discussed to establish the effectiveness and advantages of this novel technology. The technology was demonstrated using a skid-mounted unit in the Woodford trend area of Oklahoma, USA at an XTO Energy production facility. cMIST™ was tested under a range of field conditions (temperature, gas and solvent flow rates, process configurations, transient and upset) to examine the dehydration capacity, operability, and reliability.

cMIST™ relies on state-of-the-art technological advances in contacting and inline separation to achieve pipeline specification dry gas. The technology is highly modular to allow for simple transportation into remote, challenged, or offshore environments and provide installation configuration flexibility. Case studies show a 50 % weight reduction of the absorption equipment in selected applications. During EMURC's field demonstration and qualification program, cMIST™ achieved pipeline specification over a range of process conditions and during sustained operation. cMIST™ was demonstrated to have a broad application in gas dehydration.
Acid Soluble Drilling Fluids: Development and Field Trial
Authors: Wagle Vikrant , Al-Yami Abdullah S. , Al-Bahrani Hussain , AlSafran Ali
Published: November 2017

Stuck pipe can not only significantly increase the cost of drilling but also has the potential to decrease the chances of successfully drilling a well within the stipulated time. A number of techniques and tools have been developed to solve the stuck pipe problem after they occur. However, the real objective should be to avoid the problem of stuck pipe to begin with and if and when they occur, the choice of treatment to release a stuck pipe should be such that it is not only cost effective but also quick. Such an objective prompted us to develop a new drilling fluid formulated with a combination of two different weighting agents, viz. barite and manganese tetroxide (Mn3O4).

This paper describes the formulation of medium and high-density drilling fluids viz. 120 pcf and 150 pcf density fluids. These drilling fluids have been formulated with a combination of barite and Mn3O4 as weighting materials and hot rolled at 250°F and 300°F, respectively. After hot rolling these fluids at the specified temperatures, rheological properties and high temperature, high pressure (HTHP) fluid loss were measured. Sag resistance of the drilling fluids was estimated by perfoming static aging experiments in which the fluids were aged in inclined and vertical positions. To evaluate the filter-cake breaking potential of these mangansese tetroxide based drilling fluids, different breaker fluids were tested on the new 100pcf drilling fluid so as to calculate the % filter-cake removal efficiency. The paper also describes the data obtained from the field trial of 100 pcf and 145 pcf fluids formulated with barite and Mn3O4 for wells with a BHST of 290°F.

The paper discusses the benefits of using drilling fluids formulated with barite and manganese tetroxide in mitigating stuck pipe issues and highlights their benefits in terms of better barite sag resistance and lower equivalent circulating density as compared to conventional drilling fluids formulated with 100% barite as weighting agent. The 120 pcf fluid when static agend showed superior rheology, thin filter cake and better sag resistance as compared to the 120pcf fluid formulated with only barite as the weighting agent. Different filter-cake breaker fluids have been showon to partially dissolve the filter cake of drilling fluids formulated with the acid-soluble manganese tetroxide as a weighting agent. This partial dissolution of filter cake is sufficient to free the pipe in the case of any stuck pipe event in the wellbore. The drilling fluids formulated with a combination of barite and manganese tetroxide showed good rheology, barite-sag resistance and resulted in successful drilling of wells having a BHST of 290°F.
Optimized RA Sourceless LWD Suite for Horizontal Well Placement and ICD Completion Design in Middle East Cretaceous Carbonate Reservoir: A Case History
Authors: Brindle F. R. , Mishra A. K. , Altaf B. A. , Aragon J. C. , Allouti A. K. , Herz U. , Bhatt P. , Soliman A. M. , Deng L. , Hassan S. , Masry H. A.
Published: November 2017

This paper presents the successful use of LWD NMR and LWD resistivity image log technology to meet the challenge of placing wells in a thin reservoir with lateral facies variation without the use of radioactive sources and with simultaneous data acquisition to evaluate the wells and design their downhole inflow control devices (ICDs).

A series of horizontal producer wells were planned in a thin reservoir with lateral facies variation. After drilling the wells they were completed with downhole ICDs. Optimum placement of the wells within the reservoir and data acquisition to evaluate the wells and design their completions was achieved without the use of radioactive sources, as these created an unacceptable drilling risk. Rapid and accurate processing of the data in real time and subsequent design of the ICDs was required to enable the completions to run in a timely fashion. The NMR permeability was normalized using the new calibration parameters that were developed by integrating NMR results with core data, and the same relationship has been tested in other lateral wells.

Real-time NMR total porosity played a significant part in facilitating effective geosteering and well placement without the drilling risks associated with radioactive sources. In addition, the NMR provided a porosity distribution that was used to estimate a permeability index. This index was normalized using core permeability available from offset appraisal wells. The core and NMR log data in the offset wells were combined to derive the parameters for an NMR permeability relationship. The standard volumetric analysis results and the permeability index were used for identifying reservoir flow units using crossplots of normalized flow capacity versus normalized storage capacity (modified Lorenz Plots). These results were then used to develop the parameters for the ICD completions. High resolution LWD image log data was incorporated to select the best possible sections in the wells for isolation of the ICD segments. Following completion and stimulation, multiphase PLTs were run across the ICD

compartments to evaluate the wells. These results were then compared against expectations and used in subsequent well completion designs.

The results of the wells presented show that the chosen methodology enables the successful placement and completion of horizontal wells in this reservoir. Decisions about ICD completion design can be made in a timely fashion just after the drilling phase is complete, avoiding rig downtime. This approach has become the default procedure for the field and will be used for the bulk of the remaining producer wells in the reservoir.
High-Resolution Seismic Inversion Pinpoints Ultra-Thin Shale Interbeds and Sweet Spots
Authors: Tongcui Guo , Zhaohui Xia , Hongjun Wang , Liangchao Qu , Wenguang Zhao , Ping Wang , Xiangwen Kong , Li Liu , Zhi Ma , Sansheng Zhang , Jianguo Zhao
Published: November 2017

The W block shale in the study area is located at the West Canada basin and belongs to the low-porosity and ultra-low permeability gas-condensate reservoirs. The sandwiched layers in the shale are extremely important for reservoir reconstruction. As the single-layer thickness of the carbonate interbeds in the W block shale is very thin and have multi-stage superposition characteristics, the use of conventional geostatistical inversion cannot effectively and accurately predict the thin sweet spots and interbeds in the shale. This article uses three-dimensional probability constraints as pre-stack geostatistical inversion to replace traditional one-dimensional and two-dimensional face constraint inversion and achieved quantitative prediction of interbeds using well logging and 3D seismic data, so that prediction outcomes fully integrates well logging, seismic data and established a set of 3D probability constraint pre-stack geostatistical inversion process for thin interbeds and sweet spots in the shale. The process mainly includes the following crucial steps: (1) Well logging evaluation of shale reservoir parameters, analysis of shale rockphysical parameters and analysis of petrophysical characteristics of shale sweet spots and carbonate interbeds from well data, in order to evaluate and use seismic data to predict the possibility of shale sweet spots and interbeds. The characteristics of shale sweet spots is low Poisson ratio, moderate Young's modulus, high total organic content (TOC) and high brittleness. The characteristics of carbonate interbeds is high Poisson ratio, high Young's modulus, low TOC and high density. (2) Pre-stack gather optimization to establish six reliable partial sub-offset seismic data volumes. (3) Application of waveform difference simulation for prediction of shale interbeds, analysis of the vertical and horizontal variation characteristics of the interbeds based on post-stack seismic data and the three-dimensional probability volume of carbonate interbeds was estabilished according to the results of seismic waveform difference simulation and well logs. (4) High resolution 3D lithologic probability constrained pre-stack geostatistical inversion are performed and effectively predicted the spatial variation characteristics of shale thin interbeds and sweet spots.
Rapid Microfluidic Analysis of Thermal Foam Stability at 250 Degrees Celsius
Authors: Bao Bo , Sanders Aaron , Ren Ginger , Haas Thomas de
Published: November 2017

A common issue in thermal oil recovery is that a high-permeability path in the reservoir diverts steam from reaching the bulk of the pay region. Injection of thermal foams is an effective approach to improve the oil recovery factor by increasing the effective viscosity of gas phase. Conducting conventional laboratory testing on thermal foams is time consuming, often not representative of field conditions, and delivers limited amount of data. This study will outline a novel microfluidic method for rapidly screening foaming agents at reservoir-relevant pressures and temperatures. The objective of this study is to provide operators with a tool that can rapidly screen chemical additives before conducting a field pilot.

Microfluidics is the study of fluid-flow at the micro-scale (typically tens to hundreds of microns). For measurement and analysis of fluid behavior and properties, microfluidics shows unique advantages including i) fast heat and mass transfer; ii) small amount of sample consumption; iii) full-factorial multiplexed analysis. In this study, microfluidic devices are fabricated from glass and silicon wafers in a clean-room environment. A network of microscopic channels etched in the silicon wafer emulates flow through the reservoir and allows reservoir engineers to visualize the foaming process and quantify foam stability under a variety of conditions. The microfluidic device has two parallel porous media sections with two permeabilities, which allows the comparison of foam velocity.

The results of this study show that recently developed high molecular weight sulfonates, can form stable foams at 250°C. This study provides the first micro-confined visual data showing the stability of thermal foams at high-temperature and -pressure. A key observation is that the mechanism responsible for increasing the pressure-drop across a porous media may not always be the formation of foam. Some chemicals showed that deposits form in the chip and increase the pressure drop. This is proof that selecting the correct chemistry is critical to preventing reservoir damage. The speed at which the foam moves through the two porous media sections is an indication of the foam's ability to increase resistance in the reservoir.

This study demonstrates a novel approach to screening thermal foams and describes the pore-scale mechanism of foam degradation at temperature. This is the first study showing visual evidence of how thermal foams perform at reservoir-relevant temperatures and pressures (250°C and 5 MPa).
Research and Application of High-Temperature Drilling Fluid for Scientific Core Drilling Project
Authors: Wenlong Zheng , Xiaoming Wu , Yuming Huang , Jie Xu , Wenshi Wang
Published: November 2017

SK-2 Well is the main hole of China Continental Scientific Drilling Project in Songliao Basin, which was designed to penetrate through Cretaceous strata and recover a nearly complete Cretaceous terrestrial sedimentary record. Continuous coring was conducted from 2840m to 4542.24m in 311.2mm diameter with bottom hole temperature of 180°C during 10 months. The risk of sticking and collapse was very high in complicate formations, such as brittle shales and sandstone with high permeability. Design of high-temperature drilling fluid suitable for core drilling in SK-2 Well was of great importance and was in urgent practical demand.

Attapulgite was compounded with sodium bentonite to improve the bentonite quantity limit in formulating high-temperature drilling fluid, and additives of great salt resistance and thermal stability were optimized. Besides, different plugging agents were used to enhance the plugging efficiency and improve the mud cake quality. Based on XRD analysis of mineral compositions, shales hot aging recovery tests and cuttings contaminations tests, etc., a new type of polysulfonated drilling fluid system was formulated with improved rheological properties, plugging ability and inhibition.

Mud thickening rapidly after aging at 180°Cwhen the bentonite content exceeded 4%, but the rheological parameters were stable when bentonite and attapulgite addition was both 2%. Combining sized calcium carbonate with sulfonated asphalt could reduce water loss significantly, compared with the single use of them. A good inhibition effect was achieved by the synergistic effect of 7% KCL+5%polyglycols+1% polyamine.

This drilling fluid was successfully used in the 311.2mm section of the SK-2 Well, and the field application effect was remarkable during drilling process since seldom complicated conditions were encountered. Finally, 1683.17 meters long cores were recovered and the average core recovery rate was up to 98.88%.
ARC Eco-Lube - A Food Industry Waste-Based Green Lubricant
Authors: Amanullah Md , Arfaj Mohammed K.
Published: November 2017

Due to a perpetual source of various waste products, the food industry is a potential source of different raw materials for different industrial applications including the oil and gas industry. These waste products can be processed, treated or modified for various industrial uses to mitigate or overcome some of the technical challenges. For example, the waste vegetable oil generated by the food industry can be used to develop eco-friendly lubricants for exploration and exploitation of oil and gas resources without any detrimental impact to the surrounding environment, ecosystems and habitats. This paper describes an eco-friendly lubricant developed using waste vegetable oil generated by the food industry.

Experimental results indicate a significant reduction in the COF values of the water-based muds in the presence of the newly developed lubricant. Comparison of the COF reduction capability of the new lubricant with respect to non-environment friendly and poorly biodegradable diesel and mineral oils indicate better or similar performance for the newly developed lubricant. It also showed virtually similar performance in lab lubricity test with respect to a commercial green lubricant used by the industry and thus demonstrates its suitability as an alternative to commercial green lubricants. As the lubricant has been developed using a locally available food industry waste product, it will play a positive role in the growth of the local industries and enterprises. The localization of the lubricant development will create new employment opportunities for the local communities. Moreover, it will contribute in the growth of local and national economy and also in lifting the social and economic condition of the local communities.

Incorporation of the lubricant in water-based mud will reduce the COF values significantly without any change to the environmental characteristics of water-based muds. Hence, it can be used in mitigating the torque and drag problem while drilling in sensitive environments such as offshore and deep water drilling environments.