bluuebunny/crossref_metadata_2025 huggingface dataset:
The EOR Mechanism and Flow Behaviors of High-Viscosity Modified Starch Nanogel Particles in Porous Media
Authors: Liang Tuo , Hou Jirui , Qu Ming , Wen Yuchen , Zhang Wei , Wu Wenming , Wu Weipeng , Zhang Ziyi , Yang Jingbin , Xiao Lixiao , Ding Yitong
Published: October 2019

The formation of the dominant channel of water is a severe problem for most of the oilfields. Recently, gel and nanoparticles regarded as conformance water materials have attracted more attention to control water-cut and enhance oil recovery (EOR) in many water invasion reservoirs. However, nanogel particles possessing synergic properties of nanoparticles and gel are currently unavailable, which causes barrier to EOR. Here, high viscosity α-starch nanogel particles were synthesized to play the synergistic role of gel and nanoparticles economically. The average diameter of nanogel particles was 30 nm with dispersion viscosity of 250 mPa·s at 90°. Through flooding experiments, we demonstrated both light and heavy oil recovery rates reached around 30%. The nanogel particles promotes to displace oil droplets from the rock surface due the creation of the structural disjoining pressure. Also, its high viscosity properties help to drag oil clusters out of the oil phase.
A New Method to Evaluate Potential Hydrocarbon in Hard Overpressure Zone
Authors: Apranda Yoseph Robby , Riadi Ridha Santika , Nugraha Teguh , Permana Robhy Cahya , Putranto Asnanto Multa , Noerad Dardji
Published: October 2019

The Sanga-Sanga working area consists of brown fields that have been produced for nearly 50 years. The production is declining rapidly from anticlinal trap fields. Finding new resources is a must in order to extend the production life. Therefore, the exploration requires getting deeper targeting reservoirs associated with hard overpressure zones.

The methodology used to identify and recognize the potency of hard overpressure zone is the integration of geology, geophysics, and geochemistry data. Normal compaction trend and pore pressure analyses were performed to determine top of overpressure zones. The geochemical data from biomarker provide calculated vitrinite reflectance (Rc) to complement vitrinite reflectance (Ro) when evaluating relationship between hydrocarbon origin and overpressure generation. Finally, the seismic integrates all the data in structural reconstruction framework.

Pore pressure analysis showed 9 wells have overpressure zones. The overpressure occurrence can be grouped based on anticlinal lineaments. The Badak-Nilam lineament is characterized by a sharp change in overpressure to hard overpressure zone, distal facies, relatively normal deposition and showing higher pressure gradient. The Semberah and Lampake-Mutiara lineament are characterized by long transition zone, proximal facies, strongly uplifted and folded, and showing lower pressure gradient. Ro and Rc data showed that there are two periods of hydrocarbon charging into the reservoir, prior to and after the hard overpressure zone occurred. Vertical effective stress, dynamic mechanism, and the timing hydrocarbon generation-migration and overpressure generation hole significant role to accumulation.

The evaluation of hard overpressure zone play requires the integration of geology, geophysics and geochemistry to get the understanding of the timing sequence between hydrocarbon generation-migration and overpressure generation. Calculated vitrinite reflectance data from biomarker gave an advantage to this timing relationship that could lead to the exploration of the hidden resources in the hard overpressure zone becomes more feasible.
New Perspective to Unlock Opportunities in Mature Field: Sanga-Sanga Block, Indonesia
Authors: Fedriando Fedriando , Pambudi Aldy Reza , Rolanda Donna Sita , Srikandi Citra , Nugroho Agung Prasetyo , Fadhlirrahman Ahmad Arif , AD Addil , Satria Tedi
Published: October 2019

Sanga-Sanga Block is located onshore of the Mahakam delta, in East Kalimantan Indonesia and operated under Pertamina Hulu Sanga-Sanga. Nilam field, one of assets in Sanga-Sanga Block was discovered in 1974 with 75 km length. Nilam field was interpreted as the extension of Badak Handil Anticline Structure. The first well, NLM 1 was spudded on 8 July 1974 and put on production 9 years later due to waiting on surface facility. Early production was 22 MMscfd and flow directly to Bontang. At present, Nilam has reached a mature stage of its life where 364 wells drilled. The productions are continuing declining and currently 98 wells online and deliver approximately 23 MMscfd and 1800 BOPD.

There are 3 components to generate the production; they are base, rigless and new well program. New well program is main contributor to Nilam production. However, since oil price start to drop in 2014, drilling activity becomes decreased and consequently, rigless activity become the main backbone to arrest production decline. Aggressive rigless program is required to maintain Nilam production. Since 2010, total of perforated zones are 1323 and by the time, thus remaining zone candidates for rigless are decreasing. To face this challenge, integrated subsurface review has been conducted to assess several strategies to create new opportunity in delivering Nilam production. The strategies are; unlocking the hidden potential from by passed and unprognosed zones in existing well and campaign of complex rigless program to access the potential zones.

In early 2018, these strategies has already applied and already contributed 4.42 Bcf and 164 thousands of barrel oil to Nilam Field. The success ratio is 73%. It helped to sustain Nilam production and maintain the decline rate. In summary, these strategies have successfully unlocking hydrocarbon potential and maximizing recoverable reserve in existing wells which resulted in extend the field life. This paper will describe the success story to unlock gas and oil reserve in complex environment especially at Nilam Field.
Sour Gas Facilities Debottlenecking: Establishing Feasible Operational Boundaries for Higher Contaminants Processing
Authors: Muhamad Ir. Suhana , Ahmad Johari Ir. Ahmad , Abdullah Nur Hidayah
Published: October 2019

Gas fields containing contaminants continue to not only challenge new field development projects, but also existing operations worldwide. Unforeseen variables such as increasing levels of contaminants from existing fields paired with increased sales gas demands, justifies the urgent need of identifying limits and pushing boundaries of existing facilities to handle the operation parameter changes.

This study focuses on a debottlenecking study done for an existing operational facilities located at the Caspian Sea area, with an original inlet H2S design of 45 ppmv, to be processed down to < 3.5 ppmv. New sales gas demand requires for the existing facilities to process sour gas from reservoir having a maximum level of 580 ppmv H2S, at a higher continuous sales gas volume. Challenges to achieving this also includes uncertainties due to fluctuations of H2S levels from the reservoirs, with some variations going from <10 ppmv to 300 ppmv H2S coming out from the same well.

Discussion will elaborate on challenges in meeting the new sales volume with expected increased in H2S levels from existing wells, and how limitations of existing facilities (Acid Gas Removal Unit, Acid Gas Incinerators and materials sour service compatibility) are addressed to produce a feasible operating envelope, with minimal changes to existing operating facilities.

Actual operating data from approximately 5 years of operation was analyzed to determine the feasibility of the AGRU and Incinerator to handle higher H2S levels in feed. This is in anticipation of continuous feed gas volume of 500 MMscfd, at blended H2S levels of between 45 ppm to 162 ppm (worst case scenario). Existing facilities sour materials compatibility analysis are also done to determine the feasibility of the operating envelope.

In the analysis, data from actual operating history and new production profiles are plotted against a feasible operating curve developed for the AGRU. The resultant graph gives an indication of the existing AGRU capability to manage incoming increase in gas volume and H2S levels. The analysis also evaluates the impact to the Incinerators, with new emission dispersion simulations done, to ensure operating curve complies with local environmental regulations on emission dispersion.

The analyses conclude that the existing facilities is deemed adequate to handle new gas demand, with some curtailment on blended H2S levels to ensure only minimum changes and upgrades are required to existing facilities. The curves developed are hereby used as a reference for operations of the facilities in the future, whilst the methods applied here can be used as a reference for future sour facilities debottlenecking.
Numerical Simulation of Improving Cementing Displacement Efficiency under Narrow Safety Density Window
Authors: Gao Haiyang , Ai Zhengqing , Zhang Jingcheng , Zhou Bo , Chen Feng , Wang Wenchang , Liu Zhongfei , Deng Qiang , Shi Yongzhe , Wang Zhongli
Published: October 2019

As for the thick salt-gypsum formation and the target strata in the Kuqa piedmont zone of Tarim basin in western China, The biggest challenge in well cementing is the narrow safety density window (only 0 g/cm3-0.1 g/cm3 or 0ppg-0.833ppg) and the unsatisfactory leakage blocking technology under pressure (the improvement of formation pressure-bearing capacity is less than 0.1 g/cm3 or 0.833ppg). The limited flow rates (0.6m/s-1m/s lost still) during cementing operation are distinctly insufficient for displacement efficiency. In response to this challenge, a numerical simulation study has been carried out using the computational fluid dynamics (CFD) software ANSYA Fluent to explore practical guidelines in these formations.

The models we build are annulus with a 176.7mm (6 5/8 " bit expanding 5%) outer diameter for the hole and a 139.7mm(5 1/2") inner diameter for the casing, the length is 11 meters or 22 meters, and the eccentricities are 0.3, which means a sufficient centralizer according to our practical experience. The 11-meter and 22-meter models have one million and two million grids, respectively. In the thin boundary layer area four thin boundary layers were constructed. The species model and the viscous laminar model have been applied, and the velocity inlet and the outflow outlet have been set as the boundary conditions. Both the mud, the spacer and the cement slurry are non-Newtonian Herschel-Buckley(H-B) fluids, whose rheological properties are determined by the flow index n, consistency coefficient K and yield point YP. By analyzing the interface characteristics of the mixing slurry, distribution of mud mass fraction and wall shear stress at different inlet velocity and displacing time during the displacement process, the effects on the displacement efficiency for each individual factor, such as casing centralizer, flow rate, and rheological properties, have been analyzed and summarized.

According to these simulations, a series of guidelines have been drawn. A sufficient casing centralization is the most important approach to improve the displacement efficiency. Flow rate and wall shear stress also play an important role, but they are limited by the safety density windows of the formations. Under the circumstances, the most practical way to improve the displacement efficiency is to optimize the rheological parameters of the mud-spacer-cement slurry (for instance, to decrease the consistency coefficient K and yield point YP of the spacer) to achieve a larger friction gradient difference and get a better displacement efficiency eventually.

These guidelines, which have been applied in the X-well of Kuqa piedmont, have shown a remarkable achievement in cement sheath evaluation across the primary zone of interest (qualification rate improved from an average 49% to 80.3%), and therefore are practical in the formations with narrow safety density window.
Towards a Reliable Determination of Saturation Pressure: A Hybrid of Mouth Brooding Fish MBF Algorithm and Flash Calculations
Authors: Ebadi Mohammad , Koroteev Dmitry
Published: October 2019

Determination of the saturation pressure as one of the most prominent PVT properties of each oil sample has been the topic of many expensive and time-consuming experimental and numerical methods. The current research aims conducting a systematic search procedure to estimate the saturation pressure of an oil sample based on the application of flash calculations tuned with a modern optimization algorithm.

The saturation pressure is the only one at which the total product value of Zi (mole fraction of component i in the entire hydrocarbon mixture) by Ki (pressure dependent equilibrium ratio of component i) is equal to the unity. Instead of using a trial-and-error method to compute a pressure which satisfies the abovementioned condition, advantages of metaheuristic algorithms like Mouth Brooding Fish (MBF) can be utilized to evolutionarily find the saturation pressure.

The pressure of each cichild has been evaluated based on a cost function which relies on values generated with Equations of States (EOS). The squared difference between the generated output and the unity is the amount of error which has been minimized within the running of the MBF.

Whereas the determination of saturation pressure through the application of flash calculations has traditionally been a challenging case in terms of providing a proper initial guess, the proposed procedure has turned the previous method into a systematic, super-fast and programmable trend which can easily be inserted into the commercial packages of reservoir simulations.
Integrated Hydrocarbon Asset Management: Efficient Strategies and Innovative Solutions
Authors: Masoudi Rahim , Jamaludin Maisarah
Published: October 2019

The 2015 oil price downturn compounded by future uncertainties and volatility in the industry have resulted in significant transformation in many oil & gas companies towards identifying and removing inefficiencies and maximising the lifecycle value of the hydrocarbon assets. The need to take proactive action in enhancing the business workflows to improve efficiencies through process simplification, innovative collaboration models and cost reduction efforts. In the low oil price environment, we need to be more cash conscious, focusing mindset towards value & objective driven activities, while rethinking the commercial and contractual strategies.

This paper will briefly touch upon some of the process improvements at industry level in Malaysia and its key principles and value impacts, focusing mainly on Integrated Asset Development & Management (IADM) throughout field/asset lifecycle from exploration stage to decommissioning and abandonment stage. In addition, this paper will also share examples of innovative solution of resources management towards successful development plan formulation and asset management, that serve as a platform for putting together various elements of ideas and concepts, best practices and lessons learnt, techno-commercial & data-driven initiatives, alternative industry standard approaches, and enabling technologies for IADM.
Optimizing Operating Cost Through Production Management and Techno-Economic Approach in Mature Field and Gross-Split Scheme
Authors: Nugroho Wisnu Agus , Panaiputra Harris Grenaldi , Kusuma Dian Nurlita , Wirawan Alvin , Hartawan Iman Budi , Hapsari Ratna
Published: October 2019

Currently Indonesia apply new gross split production sharing contracts for the oil & gas industry. Regulation of the Minister of Energy and Mineral Resources Number 8 of 2017 on Gross Split Production Sharing Contracts sets out a new economic structure for production sharing contracts (PSC) based on dividing gross production between the state and PSC Contractors, without a mechanism for the PSC Contractor to recover operating costs. For mature field, high operating cost regarding low production, high maintenance, and integrity issues are challenging for this new regulation. To optimize operating cost with robust and prudent planning is one of the key of success in this era. Pertamina Hulu Energi Offshore North West Java (PHE ONWJ) has started gross split scheme since January 2017 which start a new era of production sharing contracts.

With the start of gross split scheme, prioritization of production is the main objective, to gain maximum productivity in terms of operating and lifting cost. The methodology to optimize operating cost is by prioritizing productive remote well platform, Normally Unmanned Installation (NUI), by ranking of potential development and its production volume. The non-potential and non-productive NUI then be assessed to be shut off or run to fail. The assessment conducted using technical and economic approach to obtain optimized result. For non-potential and productive NUI, assessment to gain more production with minimum cost is conducted. Then, development could be focused on potential and productive NUI.

Foxtrot, one of flow station in PHE ONWJ working area, has eight active NUIs that are FA, FK, FG, FFB, FNB, FWB, HZEA, and HZEB. By conducting ranking of potential development and its production volume, company could focus on five Foxtrot NUIs for development (FK, FG, FFB, FWB & HZEA), two NUIs for optimization (FNB & FA), and one NUI that potential to be shut-off, HZEB. This action on the non-potential and non-productive NUI shut off could yet decrease operating cost by IDR 8.8 Billion/ year, eliminate potential personal hazard, and reduce system's backpressure due to its low API crude oil. Oil and Gas Company that operates old facilities in mature field could apply this approach to maintain their production by focusing on beneficial asset yet decrease operating cost.
Giving a Boost to Low Pressure Gas Well by Installing Gas Ejector
Authors: Ping Wei , Brian Macdonald
Published: October 2019

To further reduce the back pressure on low-pressure gas wells and increase reserves in a mature gas field, a gas ejector project was evaluated and proposed in 2014. Following on-site tests on several gas wells during 2015 the gas ejector was successfully put into service in 2016. Reservoir simulation estimates that 6.4bcf of incremental reserves will be achieved through gas ejector installation by decreasing inlet pressure to 50 psi from 100 psi. Very low capital costs and insignificant operating costs demonstrate positive economics. Existing facilities and availability of high-pressure gas source contribute to the success of this project. The gas ejector was designed and manufactured in China at far more competitive costs that could be obtained in the international market. The application of gas ejector during the past 2 years to reduce back pressure has helped to improve the economics in a mature gas field. Figure 1 shows the location of YC13-1 field facilities.
Conforming Production Logging Tool with High-Resolution Electrical Imager in Carbonate Reservoir
Authors: Al-Khalifa Nasser , Nugroho Cahyo , Memiche Lynda , Al-Blooshi Asmaa , Tiwary Asheshwar , Al-Moraikhi Haifa , Joshi Deepak
Published: October 2019

This paper presents results from integration of Production Logging Tool (PLT) data with image facies interpretation from high-resolution electrical images in a horizontal producer well in Kuwait. The Minagish Oolite Formation is a carbonate reservoir in the Umm-Gudair field which is characterised by packstone to grainstone with oolitic rich facies. Integration of fluid contribution along the producer hole from PLT measurement with image facies from electrical image logs will support completion strategy optimization.

A PLT was deployed in horizontal producer well of 6.125 inch (bit size) with coil tubing, when both flowing as well as shut-in conditions with choke size (128+128)/64″. Liquid rate from PLT 2981 Barel fluid per day (BPD) was in agreement with surface Portable Gas Oil Ratio (PGOR) test rate (2975 BPD). During drilling, high-resolution of electrical image was acquired. The electrical image has range of conductive (darker) and resistive (brighter) features, where conductive image shows porosity such as vugs and resistive image shows less pore space such as cemented patches in carbonates.

Based on PLT measurement, entire producer section was divided into six intervals, as below Interval A has 800 feet and interval E has 150 feet with production rate 56 BPD.Interval B has 300 feet which contributes 80 BPD.Interval C contributes 100 BPD and has 75 feet lateral section.Interval D has 300 feet lateral and contributes 92 BPD.Interval F contributes maximum liquid of 2590 BPD from 1350 feet interval.

On integrating PLT and facies analysis result, it was found interval F which gave highest liquid rate of 2590 BPD has higher statistics of conductive features. Second highest production rate coming from interval C is also showing high amount of conductive image. Low production rate interval E shows lower statistics of conductive features. Image analysis shows interval C and interval F having resistive patches, dominant moldic porosity and nodular limestone. Low production rate intervals are characterized by facies of clean massive limestone with less secondary porosity.

Facies analysis was exercised using electrical image log to characterize the reservoir. Identified image facies were mottled, bioclastic, vuggy, nodular, and clean to argillaceous limestone. Facies analysis based on conductive and resistive features from high-resolution electrical image has relationship with production rate from PLT. The study concludes that electrical image can be used to optimize completion design and hence to optimize production rate.
A Real-Time Indicator for the Evaluation of Hole Cleaning Efficiency
Authors: Alawami Mohammed , Bassam Mohammed , Gharbi Salem , Al Rubaii Mohammed
Published: October 2019

Drilling operations are considered a major cost in the development phase of oil and gas wells, which places huge emphasis on drilling efficiency as a leading factor in cost reduction and optimization. Nonproductive time (NPT) incidents such as stuck pipes must be minimized by careful planning and close well monitoring to enhance drilling efficiency. One frequent and global cause of stuck pipes is the inefficient removal of formation cuttings from the wellbore while drilling, which is the focus of the developed real-time model. Poor hole cleaning is also a major contributor to other NPTs such as loss of circulation and formation fracturing, which can be induced due to the high equivalent circulating density (ECD) caused by the presence of excess cuttings. Insufficient hole cleaning, if not tackled properly and in a timely manner, can lead to NPT incidents and consequently increases the drilling cost significantly. In addition to NPT reduction, proper hole cleaning can increase the rate of penetration (ROP) and reduce torque and drag. A tool that provides a real-time indication of the hole cleaning efficiency is therefore very valuable to have better control of the hole conditions, especially in critical wells. Such indicators will provide continuous monitoring of the wellbore and will allow immediate intervention for detected abnormalities.

There are several indexes that evaluate hole cleaning efficiency while drilling. The index that will be the core of the developed model is the Carrying Capacity Index (CCI), which is defined as the ability of a mud system to circulate the cuttings to the surface. The index is influenced mainly by the drilling fluid properties and flow hydraulics, which are both controllable factors that allow the rig crew to adjust on location to ensure sufficient cleaning of the cuttings.

The developed system automatically calculates the CCI in real-time. Thousands of raw values are generated from rig sensors continuously, which makes the calculations nearly impossible for a human to perform. The model is developed to take in the raw data and use it as an input in conjunction with some well details, such as hole size and casing size, to generate the CCI. This system takes us one step closer toward the ultimate goal of having an integrated and fully automated hole cleaning evaluation and intervention tool that does not require any human involvement.
A Straight Line p/z Plot in Multilayer Tight Gas Reservoirs
Authors: Jongkittinarukorn Kittiphongs , Last Nick
Published: October 2019

Application of conventional material balance methods to evaluate multilayer tight gas reservoirs gives misleading results. This is due to the phenomenon differential depletion, as a result of which very long shut-in times are required to get the correct average reservoir pressure, and pressures from static BHP surveys are generally significantly lower than the average reservoir pressure. This study proposes a new approach which yields a straight line on the p/z plot, without a long shut-in period.

This paper proposes to use data from production logging which can be used to perform selective inflow performance (SIP) analysis. From SIP the pressure and productivity of each reservoir can be estimated independently. The average reservoir pressure of the multilayer system can then be calculated from each layer's reservoir pressure weighted by its hydrocarbon pore volume. The method therefore requires estimation of the hydrocarbon pore volume ratio (Fv). A guideline for Fv estimation and the effects of Fv on the p/z plot will be discussed in this study. With this new average reservoir pressure, material balance methods will give a straight line, similar to one for a single layer gas reservoir.

Without loss of generality, this study focuses on a 2-layer gas reservoir: a high-permeability layer (layer 1) and a low-permeability layer (layer 2). The results can be applied to multilayer gas reservoirs. Fv is defined here as the ratio of the hydrocarbon pore volume (HCPV) of layer 1 to the HCPV of layer 2. For a given Fv, together with individual layer pressures from SIP analysis, the average reservoir pressure can be calculated. Different values of Fv yield different profiles on the p/z plot. A straight line can be obtained only from the correct value of Fv. If the value of Fv is incorrect, the calculated pressure will be deviating from the theoretical straight line. High and low values of Fv lead to underestimation and overestimation of GIIP and reserves, respectively. During the early production period, most of the production is from layer 1 which dominates the early-time response. The differential pressure between layer 2 and layer 1 (p2 – p1) is increasing during this period. After layer 1 is partially depleted, production from layer 2 starts to increase significantly, and dominates the late-time response. The value of (p2 – p1) reaches a maximum and then decreasing. Beyond this point, all profiles for different values of Fv lead to the correct GIIP and reserve. Then the uncertainty will be reduced dramatically.

This study should be beneficial to engineers who wish to estimate GIIP and reserves. It is theoretically sound for multilayer gas reservoirs, both tight and high permeability reservoirs, for both with and without cross-flow. With this new approach, engineers can apply material balance methods to better understand multilayer gas reservoirs and to make better reservoir management decisions.
Breaking the Challenge of Brownfield by Delivering 10,000 BOPD with Implementation of Gas Lift Supply Strategy. The Success Story of Facility Upgrading, Integration and Optimization in Oil Field
Authors: Muhammad Kahfie Rizky , Kurniawan Farid , Saputra Reza
Published: October 2019

Sanga Sanga block has been producing for more than 50 years, with most of the oil production from depleted reservoirs with 60% of base production decline. Extending the wells’ lives requires aggressive artificial lift development both in subsurface and surface. The implementation of gas lift supply strategy is very critical to fulfil gas lift capacity requirement also with sufficient injection pressure. This paper will describe gas lift supply strategy consisting of facility upgrading, along with integration and optimization of the existing facility.

Thorough project planning and procedures have been established to ensure the optimum oil development. The gas lift facility upgrade consists of three main projects as follows. The first was a major project of an additional high pressure compressor for gas lift. One unit in the Mutiara field and two rental units in the Nilam field have been installed to increase gas lift capacity.

The second project was the installation of an interconnected gas lift network to ensure availability and coverage of gas lift system along from gas lift source to the furthest well location. The last project was the optimization of the existing production facility, injection facility and trunkline to reduce capital cost.

This project was completed as scheduled and successfully delivered 10,000 BOPD in the last four years. It was supported by an additional 27 MMscfd supply from the HP Compressor project as a gas lift source.

A length of more than 35 km of gas lift system was completed in 6 producing fields to eliminate gas lift blank spot. Gas lift injection pressure has increased from 300 - 1000 psig to 1400 to – 1800 psig, enabling more drawdown in the gas lift wells. The interconnection system installed gives two benefits: flexibility of gas lift source during compressor maintenance and also the distribution of High Pressure and Medium Pressure gas. Sanga Sanga also managed to reduce the unit price of the individual gas lift injection facility by 30% through a bulk procurement strategy, utilization of idle equipment and the modification of existing equipment.
Leveraging Oil and Gas Data Lakes to Enable Data Science Factories
Authors: Antonio Daniel , Sadlier Andreas , Winston Joseph
Published: October 2019

As oil and gas companies undergo their digital transformations, they typically first focus their efforts on analytic and machine learning solutions. They expect immediate advancements in automated operations and detecting predictive failures. The solutions generally rely on small-scale proof of concept exercises to demonstrate their worth. Far too often, this approach relies on manually collected datasets. Ironically, these consume the majority of the project's time and resources; consequently, they fall short of their promise to yield significant financial returns.

Organizations must centralize available information into a corporate data lake to enable data scientists to access all available data. New challenges also arise from information governance and data management because this data originates from different business units with their own goals and concerns. Rather than focusing on the analogy of a data lake as a storage methodology for information, it is useful to view a data lake model as a manufacturing facility that produces analytical insights and enhanced capabilities.

Just as a manufacturing facility is organized around specific processes to deliver finished goods, a data lake should provide all capabilities necessary to transform raw data into valuable assets for oil and gas organizations. The data lake must therefore feature several analogous capabilities and properties. These include a receiving dock, quality assurance/quality control (QA/QC) stations, warehousing, and tooling and engineering, as well as flexible, lean assembly lines to build new products and shipping capacity to deliver the finished goods to customers. By applying successful manufacturing techniques to the data lake design, oil and gas companies can efficiently develop and maintain assembly lines for manufacturing analytical insights.

This paper explains the similarities between delivering analytics and manufacturing processes. It also describes the data lake functionality. Each part of the process provides a critical component for generating analytical results and can be managed like its manufacturing counterpart to deliver lean processes that enable more efficient data science results.
Estimating PVT Properties of Crude Oil Systems Based on a Boosted Decision Tree Regression Modelling Scheme with K-Means Clustering
Authors: Almashan Meshal , Narusue Yoshiaki , Morikawa Hiroyuki
Published: October 2019

Machine learning has been successfully implemented for the past 20 years in estimating reservoir fluid properties competing with the empirical correlations. One of the most commonly utilized modelling schemes is the artificial neural network which is known for its black-box problem that does not show the steps taken to reach the final estimation of the fluid properties. This study offers a different modeling approach that overcomes the limitations of the current implemented modeling scheme providing users with better predications and deeper understanding of the key input parameters in modeling. The proposed model predicts the bubble point pressure (Pb) and the oil formation volume factor at bubble point pressure (Bob) as a function of oil and gas specific gravity, solution gas-oil ratio, and reservoir temperature by a boosted decision tree regression (BDTR) predictive modeling scheme. The K-means clustering algorithm is performed as a preprocessing step based on the Pressure-Volume-Temperature (PVT) input features to increase the prediction accuracy. In addition, the predictive power of the built K-means clustered BDTR model implemented in this study is compared against the most commonly used empirical correlations, the ANNs, and the standalone BDTR model. Moreover, the feature importance of predicting Pb and Bob is discussed. The universal dataset used in building the predictive model consists of 5200 experimentally derived data points representing worldwide crude oils covering a wide range of geographical regions. The built BDTR model is more accurate and it outperforms the most commonly used empirical correlations and the previous machine learning models in predicting Pb and Bob in terms of the average absolute percent relative error. Furthermore, the proposed model can be integrated into simulators and it can also be applied towards predicating other oil and gas properties, in the gas-liquid two-phase flow pattern identification, and in predicting rock properties. As an interpretable approach in predicting the PVT properties of crude oils, the proposed model can be used as an alternative modeling scheme in PVT characterization where the importance of the input features can heuristically and accurately be determined. This can be applied towards preventive maintenance and anomaly detection studies where prediction decisions can be further investigated by the interpretable representation of the decision trees. In addition, it is the most accurate model to date in predicting the bubble point pressure and the oil formation volume factor at bubble point pressure of crude oils.
Cost Effective Long Interval Wellbore Cleanout Using Wireline Technology: Field Application in Peciko Field, East Kalimantan
Authors: Rahman Risal , Siamsyah Kurniawati Pratika , Nadrul Jamal Muhammad
Published: October 2019

Mahakam field was experiencing gas production decline in some offshore wells. Previous interventions done in the past indicated the high probability of scale and sand which had reduced the production flow path, it had also prevented perforation gun from reaching the target depth in order to perform additional perforation to increase well potential.

Considering existing perforated reservoirs in the wells were still productive, Pertamina Hulu Mahakam (PHM) preferred to use well clean out method without invading/damaging open reservoirs. The additional cost of lost or deferred production was always unwanted. The deployment of traditional rig or coiled tubing unit to help restoring production came with considerable cost due to the equipment and personnel requirements. Consequently, PHM continually looked for new techniques to reduce this challenge. Milling on wireline, where applicable, was one solution since it could be performed in rig-less environment.

The delivery of wireline deployed milling services had been provided by conveying a specially designed milling tool which had its own built in control, power and drive section. The bit design could be customized to make the tool fit for specific application.

For a milling tool to operate properly on wireline, there were 2 physical principles that were needed to be dealt with; weight on bit (WOB) and anti-torque. To address this, wireline tractor was used.

This system fit perfectly with the context of mature field; simple, cost-effective, safe and easy to handle.
Application of Fuzzy Logic for Improvement of Perforation Gain Predictability in Multi-Layered Giant Mature Gas Field
Authors: Rau Irfan Taufik
Published: October 2019

A giant gas field that covers 75 km in length and 15 km in width has been producing since 1990 from approximately 1,200 wells which are located in 34 platforms. Deposited within a deltaic environment with enormous multi-layer sand-shale series, the wells undergo commingled production with an average of more than 30 reservoirs per well. With a total of approximately 700 perforation jobs included in more than 4000 well intervention jobs per year, the field is considered as the most complex field in the PSC Block in terms of operations. Prioritization of these perforation jobs are based on the perforation gain of each job. Therefore, properly estimating the perforation gain is crucial in order to efficiently and effectively manage and prioritize well intervention jobs.

Hypothetic approaches, for instance productivity index driven from Darcy's equation, may not be straight-forward due to incomplete and imprecise data measurement. Overwhelming operations workload in the field limits the number of data acquisition jobs performed. Consequently, required data to estimate perforation gain such as skin, pressure and drainage radius becomes limited. An alternative approach using artificial intelligence called fuzzy logic was introduced. Being a soft-computing pattern recognition method that allows imprecise input to yield output, fuzzy logic fits well with the nature of high uncertainty in geosciences data. The one-year study is conducted on reservoir basis using well monitoring results to split well level gas rate into individual reservoir gas rate. In order to ensure that proper data are incorporated in the model training, processes of data filtering must be undertaken. Therefore, implementing fuzzy logic to estimate perforation gain includes 3 main steps: (1) Preparing and Filtering Training Data Set; (2) Building the Fuzzy Model; and (3) Performing Blind Test.

After series of trial and error process, the model has reached its minimum error without compromising sense of engineering and generality. The fuzzy model results in 960 fuzzy rules and 5 input parameters: netpay, porosity, drawdown, mobility and water risk. Afterwards, the blind test shows that the resulting output from fuzzy logic correlates well with the realized gas rate both on reservoir level and well level, with maximum R-squared value of 0.7. The study is limited within the scope of current best practice for unperforated reservoirs and further study would be required to estimate the perforation gain from unconventional perforation methods and re-perforations. This method of estimating perforation gain using fuzzy logic has been implemented on daily basis with the aim to improve the efficiency and effectiveness of managing and prioritizing well intervention jobs in such a complex environment.
Source Mechanism and Stress Inversion for Hydraulic Fracturing Induced Microseismicity in Glutenite Reservoir
Authors: Feng Runhua , Memon Shoaib , Zeng Lingping , Xie Quan , Jia Suzie Qing , Zhang Hongliang , Du Daijun , Pu Wanfen , Sarout Joel , Sarmadivaleh Mohammad
Published: October 2019

The microseismicity associated with hydraulic fracturing in unconventional reservoir (i.e. shale gas play) has been investigated in the past several decades. Few experimental studies with respect to the focal mechanism and stress inversion was conducted, especially for Glutenite reservoir. In this study, the glutenite core was taken from the underground of 2600 m. Next, we performed scaled hydraulic fracturing tests on the cubic core (50×50×50mm) under geological principle stress condition in true tri-axial stress cell. Meanwhile, we monitored wellbore and pore pressure, and micro-seismic events during the fracture propagation from six faces of the cubic rock. Micro-seismic survey and events were interpreted to identify the induced fractures distribution in three dimension. Source mechanism and stress inversion were analyzed by moment tensor decomposition.

The correlation of failure plane from microseismicity and tested sample implied that the microseismic events were accurately localized. The distribution of microseismic events from secondary and reopening tests indicated that the hydraulic fracturing induced microseismicity are mainly caused by significant tip effect (i.e. reactivate preexisting natural fractures). Based on source mechanism analysis, we found that the most of the failure are dominated by double-couple (DC). The correlation between original principle stress state and the one from STESI inversion indicated that the direction of principle stresses, especially for σ2 and σ3 inversed from reopening test, can be highly influenced by the hydraulic induced fracture or weak planes during secondary fracturing test.
HSEQ View and Review V&R; An Initiative to Improve Health Safety Environment & Quality HSEQ Performance in WCI Division
Authors: Widodo Bayu Dwi , Therademaker Ricky
Published: October 2019

Improving safety culture is a never ending challenge in Well Construction & Intervention (WCI). WCI launched several HSEQ initiatives in 2018 with expectation to reduce numbers of incident or similar incident recurrence in WCI operation. Those initiatives are Broadcast Safety Message, I-Care Leader, HSEQ Perfect Days, Safety Stand Down, Well Sentinel, Back to Basic and View and Review (V&R). Each HSEQ initiatives were introduced to achive Company ultimate goal, ZERO LTI.

By definition, view is the act of seeing or looking at something (John Milton, 1608-1674) and review is to think or talk about something again, in order to make changes to it or to make a decision about it (https://dictionary.cambridge.org/dictionary/english/review).

View and Review from WCI perspective meaning a technique to observe a daily activities or daily situation at work-place then to discuss the act/ situation with respective personnel in order to capture the positive point as well as point of improvement from the act/ situation being captured.

Key points of this initiative are no blame culture; open mind and sharing knowledge are the utmost spirit when delivering this program. Therefore the new worker will take a lot of benefit when participating in the program and to merge their behavior in the existing safety culture of the organization.

V&R initiative is a simple initiative and effective to boost up crew safety awareness and to facilitate sharing knowledge between teammates. This initiative can be implemented by all personnel; either experienced personnel, new personnel or even a visitor. The success of a program is how easy/ simple and fun the program to be implemented because it needs to be effective to achieve the objective itself.

Delivering the program to all crew on board for sure is a challenge. Consistency of its implementation is also another challenge. Hazard and risk do exist, the way on how we prevent and mitigate is the key of excellence HSE Performance, and one of the way to achieve it is View and Review.
Advanced Data-Driven Model for Drilling Bit Position and Direction Determination during Well Deepening
Authors: Koryabkin Vitaly , Semenikhin Artyom , Baybolov Timur , Gruzdev Arseniy , Simonov Yuriy , Chebuniaev Igor , Karpenko Maxim , Vasilyev Vasily
Published: October 2019

In this paper we present a new data-driven methodology for a drilling bit position and direction determination. The model is based on machine learning approach and trained on a data collected in a real-time or near real-time: mechanical parameters of drilling, tool-face data, MWD/LWD data, etc.

The proposed methodology might be an interest for directional drilling service companies, operator companies that develop low-thickness productive strata. One of the main advantages of the proposed approach is economic efficiency which it provides due to absence of additional costs associated with payments for additional man hours for precise trajectory and direction monitoring. Methodology allows to predict trajectory at any time of drilling.

The methodology is illustrated on the historical data of drilling of one oilfield. At the current stage, the results of the testing show good quality. Blind test on 154 independent sliding episodes shows that median absolute error (MedAE) of depth, inclination and azimuth are 0.26 m, 0.25° and 0.42°. These errors will decrease after adding more wells and steps, which are described in future plans.
AGIR : One-Stop Application for Asset Integrity Risk Management
Authors: Susanti Feri , Hasanah Uswatun , Jaya Suwanto , Muttaqin Firdaus , Munir Bahrain
Published: October 2019

Major accident is one of the risks that oil and gas industries are exposed to. Although its probability of occurrence is low, the impact of this unfortunate event could result in significant losses in terms of personal safety, environment preservation, company asset, production and reputation. Therefore, risk management has to be in place, consisting of identification, assessment and prioritization of risks, followed by coordinated and economical application of resources to minimize, monitor and control the probability and/or impact of the unfortunate event.

In anticipation of potential major accident, there was an initiative to develop a system to manage risks in operations. In order to do that, a Technological Risk Assessment (TRA) study has been done for the existing facilities. As a result, technological risks, which deal with events that may have catastrophic and disastrous consequences, could be identified. However, due to operational changes, the level of risks could differ from the one defined by the TRA study. These risks are what we call "technical integrity risks".

In contrary to technological risks which are updated at every 5 years within the facility life cycle, technical integrity risks dynamically change over time in operational phase of the facility. Therefore, it was necessary to have one centralized database to register all the technical integrity risks. The database was named AGIR (Asset Global Integrity Risk) Register.

Apart from its function as a database, AGIR was developed as a one-stop application for risk management processes. All cases identified as potential integrity threats are registered in the application. A risk assessment tool is also embedded in order to guide users to perform risk assessment based on company's risk matrix in more systematic and efficient way. A TRA database is also included as reference of risk level by design, providing also the major risk register of the facilities. For cases that are confirmed as integrity threats, follow-up of actions defined is also monitored in this application. Furthermore, the application also provides dashboard function to generate reports. This application provides transparency and traceability in the implementation of risk management system. Its features could still be enriched to cope with the company's future needs with regard to risk management.