bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Solar-ESP Based Wellhead System for Remote Wellhead Operations in Marginal Oilfields
Authors: Idachaba Francis Enejo , Wokoma Esther
Published: October 2017

Marginal Oilfield status is the terminal point of all mature producing oilfields before they are finally abandoned. At this point, it becomes uneconomical for most operators to continue producing the field due to the very low oil production from the fields coupled with the increasing water cut and sand production from the wells. In spite of the low production from these fields, records show that the field still contains up to 40% of its reserves. The field at this point is either abandoned or sold out to marginal operators who manage the fields with minimal OPEX to maintain profitability. The strategies to be deployed to ensure profitability of the field must guarantee very minimal or zero OPEX both for the production and the operation of the field. Artificial lift is a technique used for increasing the flow from low producing oil wells and the Electric Submersible Pump is a tool used in facilitating the increase of the well flow especially when the crude oil production has decreased. This work presents the development of solar power driven Electric Submersible Pump (ESP) for increasing the flow from oil wells. The system operation is managed by a controller which manages the operation of the ESP. It also utilizes the ESP and the choke to control well pressure while a sand trap is inserted between the wellhead and the choke to separate the sand from the oil. The utilization of solar power for the ESP eliminates the need for other sources of power supply which require increasing OPEX costs and integration of the electronic choke enables remote operation and control of the wellhead, thus minimizing operator visits. This system will enable marginal field operators produce from remote wells with minimal OPEX. It will also enable major operators extend the production from their oil fields especially in this era of low oil prices where new explorations are too expensive to consider.
Nanoscale Flow Chip Platform for Laboratory Evaluation of Enhanced Oil Recovery Materials
Authors: Engel Michael , Wunsch Benjamin H. , Neumann Rodrigo F. , Giro Ronaldo , Bryant Peter W. , Smith Joshua T. , Steiner Mathias B.
Published: October 2017

We present a lab-on-chip platform for the experimental test and evaluation of Enhanced Oil Recovery [EOR] materials that enables direct experimental access to nanoscale and pore scale flow phenomena. The flow chip devices with nanometer scale features are made based on state-of-the-art semiconductor process technology. The chip design is highly customizable and allows for implementation of geometrical model representations (statistical and naturally occuring porosity patterns) that could be tested over a wide range of pressures and temperatures. By using representative chip implementations, we perform controlled flow experiments and lab tests for calibrating pore scale flow models. We discuss the design and manufacturing of the flow chips, report how the flow experiments are performed and how the experimental results are used to calibrate the computational flow simulations. Ultimately, the calibrated flow simulations will be used for predicting the efficiency of EOR materials in a pore scale representation of reservoir rock. The novelty of our research is that it leverages semiconductor process and device technology for EOR lab testing, enabling the experimental validation and calibration of flow through geometrical constrictions as small as 200 nanometers.
A Practical Approach to Incorporate Data-Driven 4D Seismic Inversion into Flow Simulation History Matching
Authors: Rey Alvaro , Landa Jorge L.
Published: October 2017

We present a workflow for incorporating time-lapse seismic into reservoir flow simulation models using a 3D high resolution streamline-based dynamic data integration procedure along with a data-driven 4D seismic inversion approach that generates map-based estimations of the change of reservoir pressure and saturation between two seismic surveys.

The proposed seismic history matching workflow is divided in two stages. In the first stage a probabilistic data-driven inference workflow combines multiple time lapse seismic signatures with production data to generate maps associated with the change in reservoir pressure and saturation between two seismic surveys. In the second stage, a 3D, high-resolution data integration procedure based on streamline sensitivity coefficients is applied to update the static model conditioned to production data and to the data-driven inverted 4D seismic from the first stage.

The novelty of the proposed technique is the ability to directly incorporate time lapse seismic data into the reservoir model characterization directly using the dynamic flow response from simulation. This eliminates the need to characterize uncertainties associated with traditional approaches to seismic inversion including the seismic rock physics model and poorly determined seismic parameters.

The proposed procedure is verified using two synthetic field models and is then applied to an actual offshore oil field under waterflooding. The workflow in total results in a reservoir flow simulation model that is jointly calibrated to historical production and 4D seismic data.

The streamline-based data integration provides an efficient approach to refining high-resolution or local heterogeneity and to quantify connectivity between injector – producer pairs.

The seismic data provide a critical spatial constraint for reservoir property inversion, thus increasing the reliability of the reservoir model for production forecasting and field development planning.
Improved Autodriller Performance with Direct Drillstring Measurements in the Drawworks Control Loop
Authors: Soukup I. M. , Boudreaux M. S. , Ramirez R. , Anderson J. R. , Shim J.
Published: October 2017

Precise autodriller control is critical for minimizing drilling dysfunction, maximizing tool life, and optimizing drilling performance. Measurements made as part of the control loop have traditionally been located remotely from the drillstring, and therefore, suffer from physical system states that are not directly related to the forces on the bit. As an example, weight measurements from deadline anchors are influenced by forces and physical properties of the hoisting system, which include friction effects, mud hose forces, and mechanical stiffness. Direct drillstring measurements provide more representative and repeatable measurements of forces near the bit, achieved by decoupling the physical states which are external to the drillstring system. Moreover, recent developments in sensor technology have provided wireless communication to the drillstring, which enables continuous direct drillstring measurements while drilling.

Data from an integrated direct drillstring measurement system was recently implemented into the drawworks control system of a jackup rig drilling in the Gulf of Thailand. Two test methodologies were used to accurately evaluate performance between the direct drillstring and the deadline anchor (feedback loop sensors) for weight-on-bit (WOB) control: (1) the first method required alternating the sensor sources every 400-500 ft and (2) the second method involved changing the sensors after each completed well.

Performance was studied by acquiring data while drilling under WOB control and comparing statistical measures between each sensor set. Time-domain analysis for control error was calculated to examine stability, responsiveness, and general error trends. Broad spectrum control performance was analyzed through statistical metrics and evaluated across wells as a function of depth. This paper documents these various analyses, the comprehensive results of which indicate significant opportunities for improved autodriller control, and thus, drilling performance by using measurements directly coupled to the drillstring within the control loops.

To date, the limited number of wireless intelligent sensor systems has precluded widespread adoption of integrating direct drillstring measurements into the control loop. However, recent improvements in sensor systems and the associated technology discussed in this paper, and applied successfully in the field, demonstrate the need for advancements in the control system architecture of drilling rigs. System stability and sensitivity improvements enable greater weight control to the drillstring and better translate the forces at the bit for more representative, repeatable real-time drillstring measurements. Field tests have shown significantly improved autodriller control, reduced drilling dysfunction, and increased rate of penetration (ROP), particularly at deeper hole depths, verifying the technology's application in extended reach wells.
Meeting the Large-Diameter Drilling Challenges and Securing Sustainable Performance Gains Using Hybrid Bit Technology in Deepwater Gulf of Mexico
Authors: Chowdhury Ashabikash Roy , Callais Ryckman , Rodrigue Wayne , Alferez Carlos H , Anderson Mark , Terziev Ivaylo , Angeles Magdiel
Published: October 2017

The operator is active in drilling deepwater (DW) exploratory, appraisal, and development wells in the central and western areas of the Gulf of Mexico (GOM) where water depths exceed 4,000 ft. In this demanding application, a key step to a successful well is achieving high performance in the large-diameter surface sections of the well. This important segment can start a well ahead of the authorization for expenditure (AFE) or create setbacks and added unplanned costs. Increasing the rate of penetration (ROP) and improving wellbore quality are two essential components for reducing cost of the riserless sections of any deepwater well.

Verticality must be maintained throughout the 26-in. large-diameter section to reduce casing wear and to ensure torque and drag remains minimal while drilling to deeper depths. The 26-in. hole section is drilled riserless and a high ROP generate additional savings by lowering the drilling fluid cost. The higher percentage of cuttings provides the additional equivalent mud weight so pump and dump (PAD) mud is not required. The increased ROP needs to be achieved with low vibration levels to avoid any bottom hole assembly (BHA) component failure that would necessitate an avoidable and costly round trip.

The operator has previously drilled with 18⅛-in. hybrid bits in salt and sub-salt formations and has recognized the potential of hybrid bits and their ability to drill fast with stable drilling conditions. Several drilling records have been set in this hole size. Encouraged by the performance gains and better drilling efficiency of initial hybrid bit runs, the operator planned to reduce cost of their riserless drilling section in a batch drilling program in GOM.

The 26-in. hybrid bit was implemented to batch drill three hole sections, each approximately 3,400 feet long. The operator was able to optimize the drilling parameters for each successive well due to growing confidence in the stable drilling environment. This enabled the drillers to increase the ROP and greatly improve time savings. The three intervals were drilled at ROP of 255, 308, and 379 ft./hr., respectively; breaking GOM field ROP records for each consecutive run with this operator. All three penetration rates have also surpassed the current world record ROP for this hole size. Subsequent 26-in. hybrid bit runs have established consistently higher ROP and have proven to be a significantly better solution when compared to polycrystalline diamond compact (PDC) bits.

This paper presents the details of the performance improvements achieved through the use of large-diameter hybrid bits, compares the drilling efficiency of large-diameter PDC and hybrid bits, and discusses some important design aspects of the hybrid bit that deliver stability and steerability.
A Fast and Robust Compositional, Multi-Phase, Non-Isothermal Wellbore Hydraulics Model for Vertical Wells
Authors: Putcha V. B. , Ertekin T
Published: October 2017

Production through wellbores in petroleum industry involves multi-phase flow of oil, gas and water. It is necessary to capture the effects of varying composition of phases to represent wellbore hydraulics accurately. However, a majority of current wellbore simulators prefer a ‘black-oil’ formulation due to its higher speed as compared to a compositional approach. In this work, a neuro-simulation protocol is developed for fast and accurate simulation of wellbore hydraulics in vertical non-isothermal systems.

The proposed toolbox is capable of predicting the pressure profile along a production tubing containing flow of pure hydrocarbons (C1 through C45) and water. The tool can operate within a range of flow rates, well depths, pipe diameters, inlet fluid compositions, wellhead pressures and geothermal gradients. The data for training the expert system is generated from a numerical simulator that computes wellbore hydraulics. The numerical simulator is a compositional model, which uses a two-phase equilibrium flash calculation for determining the distribution of hydrocarbon components in oil and gas phases. A two-phase drift flux model accounts for the variation in gas and liquid velocities under various flow regimes. The compositional mass balance and momentum equations are simultaneously solved using a fully implicit scheme, while the temperature profile of the well is taken into consideration in computations.

The results provided by both the numerical simulator and the tool described in this paper are compared against field data as well as numerical simulation results reported in the literature. It is observed that the average relative deviation of the results generated in this study from the field data example is 2.2 %. The average relative deviation between the numerical simulator developed and field data example is 2.4 %, showing that the expert system is capable of capturing the related physics and thermodynamics of the wellbore hydraulics phenomena. The average relative deviation between the results generated by the proposed tool and numerical simulation examples from literature data is observed to be between 3.3 and 7.1 %. The average relative deviations between results from the numerical simulator developed in the current work and simulation results reported in literature are found to be between 2.3 and 8.1 %. The variation between predictions provided by various models for wellbore hydraulics in the literature lie within the ranges mentioned above.

It is observed that the tool discussed in this paper is a fast, accurate and robust model for predicting wellbore hydraulics for compositional systems. The proposed tool also overcomes the stability issues associated with compositional numerical wellbore simulation models. Such a versatile tool can also be used for generating tubing intake curves for an unrestricted set of scenarios and for quick selection of optimal gas lift design parameters.
Evaluation and Management of Stimulation Placement Control in Cemented Sleeve Completions
Authors: Huckabee Paul , Ellis Dustin , Keable Brian , Gouthaman Varun , Ugueto Gustavo , Nasse Dave , Sawyer Jordan
Published: October 2017

An improved and systematic method to evaluate and quantify inter-stage isolation and stimulation distribution effectiveness in cemented sleeve completions has been developed. Data is presented for over 1400 stages from 24 wells in five resource play field development areas in the USA and Canada. The method includes quantification of stimulation effectiveness and communication leakage risk. An example of effective communication mitigation is included, with optic fiber diagnostic validation.

The method of evaluation includes integration of data from stimulation treatment parameters (treatment pressures, treatment rates, and proppant slurry concentrations) with bottom hole pressure and temperature sensors from both the toe-side and heel-side of the stimulation treatment bottom hole assembly (BHA). The process includes assessment of pressure differential observed across the heel-side and toe-side pressure sensors to quantify the level of toe-side communication leakage, and integration of the temperature response of the toe-side temperature sensor enables evaluation of the location of the leakage within the sleeve to sleeve dimension. One well includes validation with optic fiber distributed sensing methods.

Categorical and systematic methods to evaluate inter-stage isolation effectiveness are described, applied and compared for sleeve spacing ranging from 55 feet to 175 feet. The method and model to systematically rank the isolation effectiveness was developed to better quantify communication leakage, and the workflow is presented.Stimulation Distribution effectiveness ranged from 47% to 100%. The poorest isolation was observed in wells with 55 foot sleeve spacing (although we had one well with 55 foot sleeve spacing with 94% stimulation distribution effectiveness). We observed a general trend of improved isolation with larger sleeve spacing, however, two wells with ~ 175-foot sleeve spacing also observed significant communication leakage (76% and 81% stimulation distribution effectiveness). Amethod of identification and effective communication mitigation is described and includes observations with surface treatment pressure response. Effective mitigation is confirmed with both BHA pressures and optic fiber diagnostics. This data provides necessary input for economic justification to attempt to improve isolation methods in cemented horizontal completions.
Data Driven Assessment of Rotary Sidewall Coring Performance
Authors: Torlov Vladislav , Bonavides Clovis , Belowi Ali
Published: October 2017

This paper aims to review the quality of rotary sidewall coring service deliverables, performance of various tools and the main operational aspects from an operating company standpoint. Compilation of this document is based on 1650 selected core samples from a large dataset, acquired in a variety of borehole settings and formations using different tool types of three logging companies. The intention was to reduce bias toward certain instrumentation, and to provide mainly descriptive statistical information on core recovery and operational performance.

Formation attributes based on wireline log data, borehole environment (mud type, properties, etc.), quality of the recovered cores and type of instrumentation used were tracked for each station. Core lengths and integrity were also considered. Coring and station times were assessed on every point. Wherever possible, the core location accuracy was revised based on the post coring image log runs. The distribution of depth discrepancies was evaluated.

The assessment of rotary sidewall cores recovery based on formation, borehole properties and instrumentation types showed ranges and variability in core recovery. Correlation coefficients and principal components of borehole and formation models vary greatly depending on the input vectors. Despite the variability, having statistical records provides a valuable reference for cases of unusual performance. Recovery distribution was assessed for every tool type and compared to the specifications. When available, a real time recovery indicator usually provides fair estimate of expected recovery. Revised core traces on the post coring borehole images showed, that despite depth control procedures, the distribution of the assessed core depths indicated minor upward shift.

This publication presents an informative reference for geoscientists and petroleum engineers, in terms of rotary sidewall coring service product quality. It reveals the range of operating environments for a large variety of formation and borehole properties, linked to core recovery. Derived conclusions are based on performance statistics from field coring jobs, including most of the current tool types offered by major logging providers.
Resolution and Accuracy of Neutron-Gamma Density Measurements Compared to Conventional Gamma-Gamma Density Measurements
Authors: Luycx Mathilde , Torres-Verdín C.
Published: October 2017

Density measurements are widely used for the in-situ assessment of formation porosity. Traditionally, bulk density is measured with a Gamma-Gamma density tool using a radioactive chemical source. Neutron-Gamma density was recently developed to infer porosity with non-chemical sources. It is therefore imperative to quantify the differences in spatial resolution and accuracy between the two measurements and the corresponding impact on petrophysical interpretation practices.

We designed a theoretical, albeit practical logging-while-drilling (LWD) Neutron-Gamma density tool and optimized source-detector spacing for maximum accuracy. The tool design comprises a 14 MeV neutron source, two gamma ray detectors and two fast neutron detectors. Counts ratios are used to establish a linear relationship with formation bulk density. This design yields an accuracy of 0.0147 g/cm3 in shale-free formations, and 0.0182 g/cm3 in shales, to be compared to the accuracy of traditional Gamma-Gamma density measurements (0.015 g/cm3).

Neutron-Gamma density uses inputs from all four detectors in an effort to set apartCompton scattering effects needed to calculatebulk density. Consequently, the spine-and-rib correction technique is not implemented in real time, leaving the measurement vulnerable to borehole environmental effects and mainly standoff. Standoff should be limited to 0.25 in for light mud, leading to a 0.05 g/cm3 correction ofbulk density. While the vertical resolution of Gamma-Gamma density is approximately 1 ft, results obtained from synthetic cases show that the vertical resolution of Neutron-Gamma density is limited to 2.5 ft. The vertical resolution of Neutron-Gamma density competes against improved depth of investigation. Neutron-Gamma density is less affected by invasion than Gamma-Gamma density. Depth of investigation of Neutron-Gamma density is approximately 9.5 in, i.e. twice as long as the depth of investigation of Gamma-Gamma density (~4 in). The main technical challenge of Neutron-Gamma density is measurement reliability across diverse solid and fluid rock compositions. Synthetic examples show that the tool design accurately resolves formation density in shale and shaly formations, high-density formations such as anhydrite, and formations saturated with low-density gas. In these cases, the accuracy is similar to that of Gamma-Gamma density and the measurement remains reliable for porosity estimates within +/- 1 pu.

We introduce a new tool design for a radioisotope-free, in-situ measurement of bulk density based on two-particle transport. This optimized tool design is the first one to provide an accuracy that compares to Gamma-Gamma density in clean and shaly formations. Synthetic cases serve to compare the measurements and provide insight about the conditions when Neutron-Gamma density can be used as an alternative to Gamma-Gamma density while achieving equivalent accuracy and performance.
The Changing Shape of Petroleum Engineering Education
Authors: Ershaghi Iraj , Paul Donald L.
Published: October 2017

In this paper, the focus is on the changes happening in the oil industry and the evolution of new tools and technologies transferred from other fields aiming to make the industry, more efficient and more acceptable to the consumer base. The discussion about the changing trends in petroleum engineering education is primarily focused on the U. S. producers. But some of the observations may equally apply to other national oil producers.

Currently and for the foreseeable future, oil and gas will continue to be the world's primary energy feedstock. This means that petroleum assets are as critical as they have been during the last century to meet the energy demands globally. If the industry continues its mission in providing oil and natural gas resources to the world communities, it will need the services of appropriately skilled professionals. Oil industry hires many technical professionals. At the core, however, there are unique petroleum engineering concepts and domain knowledge that defines the industry and its technology base. It probably fits better in describing the sciences and techniques as a broader base of subsurface engineering1 rather than energy engineering. This particular domain expertise can be gained in depth via formal university degrees or summarily through continuing education courses and augmented with on the job training.

The oil industry is changing, and parallel to that, are the expanded core competencies needed to take new directions. Some major emphasis areas affecting the shape of petroleum engineering education include technology transfer from the fields of information sciences, medical imaging, and human factor engineering. These all influence the core educational preparation of the petroleum engineering professionals. We discuss the history of PTE (petroleum engineering) education and the evolution of the industry and its manpower needs. As an example, we consider the petroleum engineering program at USC and review how, in response to the changing trends in the oil and gas operations, engagement with the industry has been helpful in opening new directions and changes in the academic educational content offered to the graduates. Utilizing case studies and experiences from the USC program, we illustrate the larger trends which have wider application to the industry and to changing the shape of university petroleum education programs.
Impact of Conveyance System on Reservoir Characterization: New Opportunity for Highly Deviated Wells
Authors: Raffaele V. , Pampuri F. , Terzuoli S. , Santo A. , French D. , De Clemente A. , Ciulli L. , Rinaldi R.
Published: October 2017

The recent trend toward drilling horizontal wells with complicated geometries in complex reservoirs has led to operational challenges. While LWD logs are often well suited in these environments, circumstances such as very small wellbores, tool availability, and high costs sometimes lead to a search for alternative means of acquiring a full suite of formation evaluation data.

The objective of this paper is to show how, in a very complex reservoir, the choice of conveyance system can be strategic, particularly in the context of data quality and risk mitigation.

The conveyance system considered is comprised of wireline tools which are housed inside drill pipe. When the borehole assembly reaches the toe of the lateral, a dart is pumped down, which releases the formation evaluation assembly and turns on the data acquisition. As the pipe is tripped out of the hole, the tools acquire data in memory.

The presented case study considers a field in Southern Europe where a fractured carbonate reservoir is developed with horizontal wells. Characteristics of the reservoir are very high resistivity, wellbore stability issues, presence of asphaltenes, and 6″ bit sizes. To fully characterize the reservoir properties and understand the natural fracture networks, electrical imaging, gamma-ray, dipole sonic and caliper data were acquired.

The integration of the dipole sonic and electric image logs provided the basic information to perform the matrix and the fractures evaluation as well as the anisotropy orientation and the best fluid path characterization. The availability of mechanical caliper led the decrease of the uncertainty in the interpretation and the optimization of the lower completion placement.

A comparison between LWD and WL image logs is presented to rate the real added value of the wireline acquisition.

This new approach using an alternative conveyance system enabled proper reservoir characterization. In addition to the high quality of the results there was also a reduced exposure to potential risks including stuck and lost in hole tools. The general pros and cons as well as cost considerations are discussed.

While the conveyance system is generally considered a drilling focused solution and is therefore most influenced by operational challenges, it should also be considered an additional resource for the petrophysicist and geologist performing essential data interpretation as proven by the presented case study.
Sequence Stratigraphy and Sedimentary Environment Identification Based on Palynological Analysis
Authors: Gao Y. , Liu Z. , Liu S. , Luo H. , Zhang W. , Zhu Y. , Tian C.
Published: October 2017

The subsurface identification of sequence stratigraphy and sedimentary environment commonly has a high uncertainty due to the ambiguity, low-resolution, or discontinuity of seismic data, wire log data, core description data or outcrop data. However, palynology can provide a relatively precise paleoecological and paleoenvironmental results and thus can be used as an explicit lateral correlation indicator for geologists. This paper shows a sequence stratigraphy and sedimentary environment determination case primarily based on palynology for the Upper Main Pay Member in Rumaila oilfield in Iraq.

640 samples in 8 wells were analyzed and grouped which occupied 93 palynological spices. They were clustered into 6 groups, including terrestrial algal group, arid terrestrial taxa group, wetland terrestrial taxa group, least marine dinocyst (dinoflagellate cyst) group, medium marine dinocyst group and most marine dinocyst group. The vertical and lateral changes and its rules of total counts and diversities for each group were studied after appropriate statistics based on their similarities and facies intervals.

The distribution and variation of each groups from bottom to top and from proximal-source to distal-source showed some interesting and regular trends which could be associated to the results of sequence stratigraphy evolution and sedimentary environment switch. The arid terrestrial taxa group was a good indicator of the distance from the sea and of the transgressive process, which implied a continuous transgression process in the study area. The wane and wax among the least marine, medium marine and most marine dinocyst groups manifested a relatively variable salinity paleoenvironment. The simultaneous occurrence of peak total counts of the least marine dinocyst group and terrestrial algal group, combining with the relatively low total counts of the arid terrestrial taxa group, suggested a barrier island paleoenvironment. In total, the variety of the palynology in lateral and vertical dimensions recommended a transformation environment from delta to estuary, which is very difficult to be determined by other kinds of data. After the reconstruction of sedimentary environment, the influential factors, the sources (allogenic or authigenic) and the transportation processes about the terrestrialalgae, spores and pollen, and dinocysts were studied, integrated with energy distribution of estuary model.

The grouping and interval samples summing statistics of palynological spices showed perfect assistances and verifications for the sequence stratigraphy determination and sedimentary environment identification. This could be helpful for lowering the uncertainty of geological studies, especially for the complex and ambiguous formations.
New Applications of Multidetector Pulsed Neutron Technologies in Gravel Pack Completions
Authors: Han Xiaogang , Scott Manasi , Schoepf Virginie , Mousavi Maryam , Stewart Carlos , Zett Adrian
Published: October 2017

Gravel Pack (GP) and Frac Pack (FP) are common sand control completion designs. There are various well known methods to evaluate effectiveness of gravel placement in the screen - casing annulus, allowing top of pack detection, void location and gross pack quality assurance. The increasing trend in using Non Radiation Traceable (NRT) proppant in both open and cased hole completions assists the evaluation of pack quality when using pulsed neutron logging technologies. Unlike traditional GP and FP evaluation techniques, Multi-detector Pulsed Neutron (MDPN) instrumentation provides a broader suite of nuclear attributes that can be used both qualitatively and quantitatively. Moreover, MDPN data can provide a baseline fluid saturation as has been widely documented.

Multiple datasets obtained from yard tests and two observation wells have been used to benchmark theoretical models based on multiple tool response equations. MDPN time lapse data and other static and dynamic log data will be discussed to emphasize the value of NRT proppant and MDPN surveillance during well life. The complexity of the logging environment means that a huge amount of rigor is required in the areas of job planning and execution in order to ensure the resultant dataset is optimized for use quantitatively. It is possible to generate a GP Quality Index scaled from 0% (no pack) to 100% (perfect pack) using one or more nuclear attributes depending upon the environmental conditions.

This paper will describe the advantages and disadvantages of each of the conventional GP evaluation techniques based on datasets from both yard test and live wells.

For NRT / MDPN applications, the processed nuclear attributes resulting from the NRT/MDPN GP evaluation show reduced uncertainty when compared with the conventional logging techniques. Using MDPN for GP evaluation also means this data can be used for other reservoir and well surveillance applications.
In-Situ Estimation of Relative Permeability and Capillary Pressure from the Joint Inversion of Array Resistivity and Formation Test Data
Authors: Liang Lin , Zhu Jianmin , Wang Fan , Chen Jie , Habashy Tarek M. , Abubakar Aria
Published: October 2017

We present an approach for estimating in-situ relative permeability and capillary pressure through the joint inversion of array resistivity logging and formation test data. Considering a scenario of drilling a vertical well into an oil-bearing formation with water-based mud, the mud-filtrate invasion process can be regarded as a controlled experiment under reservoir conditions. Array resistivity logging can sense the formation resistivity perturbed by the two-phase flow invasion. Formation testing with fluid sampling can also provide information on the radially varying saturation and the associated changes in mobility, as well as information on the effect of capillary pressure. A facies-based workflow is developed to invert for the relative permeability and capillary pressure from the abovementioned two data sets. The inversion strategy is adjustable based on a sensitivity analysis as well as on the data available and the operational sequence of collecting the data. A hybrid inversion framework combining deterministic and stochastic optimization approaches is developed for the inversion of the data.
FracBot Technology for Mapping Hydraulic Fractures
Authors: Al-Shehri Abdallah A. , Akyildiz Ian F. , Servin Jesus M. , Schmidt Howard K.
Published: October 2017

Miniaturized transponder systems for mapping hydraulic fractures, monitoring unconventional reservoirs and measuring other wellbore parameters are under development. These devices, called FracBots (Fracture Robots), are envisioned as an extension of RFID (Radio Frequency IDentifcation) tags to realize Wireless Underground Sensor Networks (WUSNs) for mapping and characterization of hydraulic fractures in unconventional reservoirs. When injected during hydraulic fracturing operations, autonomous localization algorithms could be used to build up 3D constellation maps of proppant bed placement. To explore this concept, a FracBot prototype platform was developed, with which three key functions have been demonstrated, and are here reported. First, we developed a novel cross-layer communication framework for Magnetic Induction (MI) -based FracBot networks in dynamically changing underground environments, combining joint selection of modulation, channel coding and power control, a transmitter-based CDMA scheme and a geographic forwarding paradigm. Second, we developed a novel MI-based localization framework which exploits the unique properties of the MI field to determine the locations of the randomly deployed FracBot nodes. Third, we developed an accurate energy model framework for a linear FracBot network topology that gives feasible FracBots' transmission rates and FracBot network topology while respecting harvested energy constraints. Future work will include design and fabrication of miniaturized MI-based FracBot nodes for evaluation in a physical WUSN testbed.
Laboratory Evaluation of a Natural Gas–Based Foamed Fracturing Fluid
Authors: Beck Griffin , Nolen Craig , Hoopes Kevin , Krouse Charles , Poerner Melissa , Phatak Alhad , Verma Sandeep
Published: October 2017

Foams have been used as hydraulic fracturing fluids to reduce water usage and minimize the potentially deleterious impact on water-sensitive formations. Traditionally, carbon dioxide (CO2) and nitrogen (N2) have been used as the internal phase in these foamed fluids. Hydraulic fracturing with natural gas (NG) is a relatively inexpensive option, particularly if NG produced from the wellhead can be used without significant processing. In an ongoing program sponsored by the US Department of Energy (DOE), an alternative fracturing process is being developed that uses NG-based foam. Previously, the optimal thermodynamic pathway was identified to transform wellhead NG into pressurized NG suitable for use as the internal phase in a foamed fracturing fluid. Recent work has focused on preparing a NG-based foam at surface conditions typically encountered in hydraulic fracturing and measuring the stability and rheological properties of the foam. In addition, the transient response of the foam during fracture initiation was simulated using a fast-acting solenoid valve. A single base-fluid mixture was prepared by combining a commercially available viscosifier and foaming surfactant with water. The base fluid was then injected into a tee using a water pump. Simultaneously, liquefied natural gas (LNG) was pressurized using a cryogenic pump, vaporized using a heat exchanger, and injected into the tee to mix with the base fluid and generate foam. The foam then flowed through approximately 300 ft of 0.312-in. inside diameter (ID) tubing equipped with pressure transducers at several locations. The test fixture included a sight glass to visually inspect the quality of the foam. This paper reports on findings related to foam stability and rheology and compares these results to previous studies on foamed fracturing fluids.
Members in Transition: Career Planning, Job Search, Entrepreneurship and Innovation
Authors: Howes C. Susan , Hite J. Roger , Clute-Melancon Daniel De
Published: October 2017

The Members in Transition (MiT) initiative was established by the Society of Petroleum Engineers (SPE) Gulf Coast Section (GCS) in response to the downturn in the industry. Career transition can be defined both as a category for members who are waiting to land a job, and those who are employed, but looking to transfer their skills to other sectors of the oil and gas industry. The function of the MiT initiative is to disseminate best practices in career planning, job search, entrepreneurship and innovation. MiT events allow those in transition to feel the support of their colleagues in the Society and create opportunities for reciprocity where one can help one's colleagues. MiT activities provide learning opportunities to enable participants to rethink fundamental strategies and to find new ways to survive the downturn conditions.

The SPE-GCS has prepared a process guide to help other SPE sections to set up their own local MiT initiatives. The SPE-GCS MiT initiative includes:

A monthly seminar series Access to free computer software licenses and training Ideas Launch Pad, a relationship with the Houston Technology Center to encourage entrepreneurship Pay-it-Forward Networking Tours, Training and Panels Job Search Work Team, small groups who meet weekly to work on their job searches together, a concept based on Orville Pierson's books on job search. A career fair heldregularly

Starting in early 2016, the first five methods listed above have been deployed with strong participation. The sixth method, the career fair, was initiated in 2017. While a MiT survey was used to collect demographics and feedback, the more useful measure of the success of this initiative will be how many SPE members return to an employed state in the energy industry after spending time in transition. The downturn has caused several members to consider entrepreneurship and innovative business schemes as a replacement for fulltime employment. Disruptions cause people to rethink their standard processes, or way of doing things, and look for ways to do them more effectively and efficiently. This focus on entrepreneurship and innovation will continue to provide value to members, even after the downturn ends.

The SPE-GCS collaborates with other technical and professional societies to provide resources for members in transition. SPE-GCS partners with the Houston Technology Center (HTC), the largest technology business incubator and accelerator in Texas, advancing the commercialization of emerging technology companies in the greater Houston area. The MiT initiative launched by the GCS has been complementary to the support that SPEI provides globally via the MiT toolkit and Journal of Petroleum Technology (JPT) articles profiling perspectives of SPE technical directors and leaders.
A Robust Model to Estimate the Mud Loss into Naturally Fractured Formations
Authors: Bychina Mariia , Thomas Gevargis M. , Khandelwal Ravi , Samuel Robello
Published: October 2017

Drilling through naturally fractured formations results in multiple complications; fracture ballooning and loss circulation are predominant among them that requires more understanding of the process. In order to better understand the mechanism behind fluid loss into the natural fractures a new model has been developed which addresses the shortcomings of pre-existing models.

The paper presents a new comprehensive analytical model; represented by partial differential equation that can be used for various fluid rheologies and thus, eliminating the need for different models for different fluids. The model also takes into consideration of fracture deformation with constant and variable leak off rates into the formation. The proposed model was validated by reducing it to the preexisting models by incorporating their assumptions into it. The model has also been validated using synthetic as well as multiple field data. Sensitivity analyses were performed to determine the effects of fracture normal stiffness, leak off rate, mud-yield stress, aperture and other parameters on fluid losses. The new model presented demonstrates that fracture deformation and leak off pressure play important roles in the determination of fluid loss into the formation. The results have shown that by neglecting the fracture deformation or leak off results in the under estimation of fluid losses. It has also been found that the fluid Yield stress plays an important role in preventing fluid loss into the formation. Sensitivity analysis shows that once the pressure potential falls below the yield stress value, the fluid migration into the fracture is stopped.

The novelty of the proposed model lies in the fact that it can be used for different drilling fluids and also more generic. It takes into account fracture deformation and leak-off into the formation which lead to more accurate estimation of fluid losses than the existing models.
New Technology Provides Zonal Pressure Maintenance in Single Trip Multizone Completions
Authors: Hamid Syed , Jannise Ricki , Garrison Greg , Coffin Maxime
Published: October 2017

This paper describes the development and testing of an innovative downhole zonal pressure maintenance device (PMD) developed for open and cased hole well completions. This PMD will be deployed as an integral tubular component in a generation IV single-trip multizone sand control system (STMZ) currently run in deep water and in other unconsolidated soft-rock applications. It will significantly increase the system's capability and provide proven time-saving benefits of such technology into the soft-rock formation arena.

Typical generation IV systems currently used isolate the discrete zones from one another and the wellbore. The operational steps include setting the top-most packer first. This process isolates the zones from the hydrostatic overbalance pressure, creating an opportunity for uncontrolled crossflow among zones with differing bottomhole pressures. This crossflow can, and will, move hydrocarbons as well as formation sand into the wellbore therefore certain limitations are placed on the existing STMZ system. The PMD maintains the initial hydrostatic pressures on each zone independently to help prevent uncontrolled crossflow and its detrimental effects. The PMD construction is totally mechanical and fully autonomous, not requiring any signals from the surface for its operation. It has built-in intelligence to sense the array of initial hydrostatic pressures in various zones and to store them for subsequent use.

Prototype tools were developed and tested in the laboratory, simulating near realistic multizone completion operations. The PMD design enables the amount of fluid leakoff into the formation to be minimized, thereby reducing formation damage. This capability is accomplished by automatically adjusting the PMDs to the respective zones to reflect the individual differences in reservoir pressure; it is particularly useful for completing wells wherein significant differential pressure exists between compartments because of the depletion that has occurred in some reservoirs.

The paper illustrates expected results on a multizone completion and displays the pressure maintenance behavior resulting from the use of this device.

Tests were conducted in the laboratory to validate the tool performance under extreme conditions of high leakoff rate in conjunction with an abrasive fluid with plugging tendency (oil-based mud). Another condition simulated relatively high pressure differential (2,000 psi) while reversing out after a "frac pack" operation.

The tool design incorporates state-of-the-art technologies, such as 3D printing and hydraulic miniaturization using implementation techniques unique to oilfield applications. Generation IV single-trip multizone system technology has been a key enabler for formations, such as those found in the Lower Tertiary of the Gulf of Mexico. The PMD provides a novel tool to extend these multizone applications to unconsolidated formations and to multizone reservoirs with high reservoir pressure differentials.