bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Approach to Restore Integrity to Downhole Safety Valves from Damaged Landing
Authors: AL-Mutairi Ali , Sayed Mohamed El , Ali Mohamed Saleh , Bhatti Ali 
Published: November 2016

Abstract
Well Integrity management standards require wells to be equipped with two independent barriers to protect against uncontrolled flow of hydrocarbons from the reservoir to the environment. For producing wells the two barriers are usually the downhole safety valve and the surface X-mas tree. I-DHSVC is integral solution, implemented 1st time in region, for wells suffering from damaged DHSV landing nipple profile. Damage could be related to lock profile, seal bore profile or both. It's a perfect solution for the wells with damaged DHSV landing nipple but with integral control line.
Sometimes, DHSV cannot be stay in the landing nipple due to damaged lock profile, causing it to pop up during the production. This situation leads to high risk scenario (risk rank-1). IDHSVC does not use damaged nipple profile for anchoring as its slips anchor in the flow coupling above & below the landing nipple. A standard DHSV is connected to bottom of IDHSVC, which sets by either Slick line or by E-wireline utilizing nitrogen charged hydraulic setting tool. DHSV can be operated normally using existing control line. IDHSVC can be retrieved utilizing slick line with GS pulling tool without any Barge/Rig.
The benefits from the project are sustained "year-on-year" with the restoration of full integrity to the wells which enables ADMA-OPCO to meet its production targets in a cost effective manner.
HSE Governance Concerns and Challenges in a Potential Oil and Gas Producer
Authors: Ibrahim Assem Abou , Sheikh Rola , Rachid Grace 
Published: November 2016

Abstract
With the latest discovery of oil and gas fields in the Eastern Mediterranean region, the concern about safety accidents and oil spills in this fragile social and natural ecosystem is continuously increasing. This paper discusses the approach of the Lebanese Petroleum Administration (LPA), as the upstream oil and gas regulator in Lebanon, towards proper health, safety and environment (HSE) management of the upcoming oil and gas sector. The potential challenges to the sector are excacerbated with existing inconsistencies in regulations, conflicting mandates, weak enforceability, lack of resources and political conflicts. A review of the existing HSE legal and regulatory framework was undertaken to identify gaps and challenges in addition to the mapping of relevant stakeholders. In parallel, a benchmarking of international HSE goverance and management systems in the oil and gas sector was necessary to gauge latest approaches and best practices in the industry to guide the development of a HSE framework in Lebnaon. The analysis covered the characteristics and implications of each of the prescriptive, risk-based and hybrid approaches to HSE management. It highlighted the importance of a very clear distinction between the authority that issues the operating licenses and the authorities that regulate safety and environment in order to prevent conflict of interest and install a natural checks-and-balance system. The study proposes a risk based hybrid HSE governance framework for implementation in Lebanon, as well as, develop a roundmap for the development of this HSE regulatory framework. In parallel, and based on lessons learnt from the Jiyeh 2006 oil spill, the largest oil spill in the Eastern Mediterranenan, an update of the national oil spill contingency plan is undertaken in light of IMO and IPIECA guidelines. This study reconfirms how benchmarks, case studies and context analysis can effectively inform governance in emerging structures facilitating necessary mindset shifts and mainstreaming the needed HSE culture.
Uncertainty Quantification in the EUR of Eagle Ford Shale Wells Using Probabilistic Decline-Curve Analysis with a Novel Model
Authors: Zhukovsky Isaac D. , Mendoza Ruben C. , King Michael J. , Lee W. John 
Published: November 2016

Abstract
This paper proposes a Bayesian decline curve methodology, using Markov Chain Monte Carlo (MCMC) simulation and a novel empirical decline curve equation (Zhang et al., 2015) to better quantify uncertainty in estimated ultimate recovery (EUR) for oil shales. The methodology was calibrated using hindcasting of production data from an area of the Eagle Ford oil window. Hindcasting, on an areal basis with 254 wells has demonstrated good results, with a coverage rate of true reserves of 78% for an 80% confidence interval (P90-P10) or 199 of the 254 wells tested. The novelty of the new model is in the implementation of the empirical decline curve equation for shale wells in Bayesian decline curve analysis with fast per well solution time on typical engineering computers
This method offers many benefits. Principally, the method quantitatively assesses uncertainty and avoids subjective estimates of uncertainty. The results the method generates are accurate for shale wells because the decline curve equation was empirically designed for such wells. Furthermore, it generates replicable results for given wells regardless of the forecasting engineer and offers a fast calculation time of 5-10 seconds per well in the data set.
The novel decline curve equation used in this methodology accommodates both early steep rate decline and later shallower decline with a smooth transition. Coupled with a Bayesian decline curve analysis process, the decline behavior of shale wells was assessed probabilistically with accuracy. The decline curve parameters are random variables with defined prior distributions. A MCMC simulation was performed to obtain the posterior distribution of well EUR's. Wells in the sample set had &gt;36 months of production with the first 12 months used as simulation input. The method was calibrated (hindcasted) on an areal basis by measuring the coverage rate of "true reserves." The method, when applied to the Eagle Ford oil shale production data, demonstrated good convergence to stationary posterior distributions of the parameters. This is important because field development of the Eagle Ford and other shale plays is improved when uncertainty is accurately quantified. By quantifying uncertainty and moving away from deterministic decline curve analysis using equations designed for conventional reservoirs, a better understanding of shale well EUR and behavior throughout a play is obtained.
Integration and Data Analysis of Conventional Core Data with NMR and CT Data to Characterize An Evaporitic Carbonate Reservoir.
Authors: Fitzsimons Daniel , Oeltzschner Gunnar , Ovens Christopher , Radies Dirk , Schulze Frauke 
Published: November 2016

Abstract
Acquisition of whole core data allows detailed rock typing profiles to be defined which are required to assign flow properties for dynamic reservoir simulation. Conventional core analysis provides lab measurements of porosity, permeability and pore size distribution sampled at plug locations with a limited sampling increment. Whole core CT scanning allows for a more continuous detailed evaluation of the cored intervals which allow the precise boundaries of specific Rock Types to be defined. This paper illustrates how novel techniques of data analysis and graphic displays of both whole core CT data and wireline NMR have been used to aid the definition of Rock Types and Flow Units.
Rock Types have been categorized based on flow properties using plug porosity, permeability and MICP data. Processing of whole core CT data and wireline NMR has been performed in order to assess the heterogeneity measured by both acquisition methods. For the CT data set Heterogeneity Logs have been generated, these logs display the variation of CT density of the whole core. The logs have enabled very fine scale definition of lithotypes. In a similar manner the NMR logs were also analyzed and processed to extract specific statistical moments such as modes, magnitudes and skewness. Both sets of data were then integrated with core analysis data and thin sections. Excellent correlation between core plug, CT Heterogeneity Logs, NMR and thin section pore size distribution was observed and this has enabled the definition of Rock Types from the fine scale CT Heterogeneity Logs and Flow Units from the coarser scale wireline NMR data.
The techniques described are applied to data from a heterogeneous evaporitic carbonate reservoir, where pore size distribution has a major effect on permeability and productivity. Eight Rock Types have been categorized from core analysis and these have been propagated from plug locations using the CT Heterogeneity Logs to assist manual interpretation. Neural Network and geostatistics were applied to propagate to uncored wells and throughout the geocellular model.
The acquisition of core data and subsequent Heterogeneity Logs from whole core CT has proved very beneficial in the understanding of the wireline NMR tool response and has given confidence in the predictive ability of NMR to distinguish reservoir Flow Units in uncored intervals or wells.
First Successful Cuttings Reinjection CRI Operation in Ecuador: An Alternative to Help Minimize the Environmental Impact in a Protected Area
Authors: Romero Luis , Ramirez Orlando , Hernandez Rubys , Bastidas Alejandro 
Published: November 2016

Abstract
This paper discusses a technology for waste management and disposal through cuttings reinjection (CRI). The fully integrated process was successfully applied in the Ecuador Apaika-Nenke field, which is an area with significant oil potential located in the heart of a protected biodiverse zone. The advantage of the applied process, from candidate selection screening to the detailed implementation phase, represents a permanent drilling solution in environmentally sensitive areas.
This paper presents a case study of CRI in an Apaika injection well. The well was chosen based on feasibility tests and previous injectivity test results, making it the first drilled waste reinjector well in Ecuador supported by best practices. This paper describes injection equipment used for the slurry process and injection into the formation, waste collection and transportation from the rig site to the CRI facilities, slurrification process describing how the cuttings are treated for reinjection, injection parameters given by the feasibility study, and pressure response to injection explaining how the formation will react in time to the slurry injection. Each slurry injection was performed in 12-hour cycles instead of continuous injection, allowing the formation to reach pseudoequilibrium stages while the cuttings migrated within the selected structure through fracturing conduits.
From June 2014 through December 2015, 209,000 bbl of slurry from 11 drilled wells were injected into the disposal well. All the waste fluids (dewatering water, cutting pits rainwater, and rig wash) were used for the preparation of injection slurry, reducing chemical use for the dewatering process. The well was also used for disposal of produced water with more than 400,000 bbl injected. The cyclic injections were conducted in three stages: preflush, post-flush, and slurry injection pumping to displace the entire tubing volume and minimize well plugging risks. During the first stage, wellhead pressure and slurry properties were monitored to help establish accurate injection parameters. No significant changes were observed in terms of pressure performance at a maximum pressure differential of 2,000 psi during the three stages. The first CRI met all expectations of not leaving any cutting on surface. All the cuttings and drilling waste from the Apaika-Nenke pads were reinjected without any operational inconvenience. For future wells, deforestation will not be necessary for new cutting pits in this sensitive area, helping minimize the environmental impact and addressing social challenges and inherent risk present within the oil industry.
The application of CRI in the Apaika-Nenke field demonstrated that drilling in a sensitive area could be performed with high environmental standards and in compliance with local environmental laws with excellent results.
Timelapse Borehole CSEM for HC-Saturation Monitoring in the Bockstedt Oilfield Onshore NW Germany
Authors: Tietze K. , Ritter O. , Patzer C. , Veeken P. , Verboom B. 
Published: November 2016

Abstract
Production from oil fields requires monitoring of hydrocarbon saturation in the reservoir. In the Bockstedt oilfield there exists a substantial difference in resistivity between oil-filled (approx. 100-16 Ohmm) and brine-filled (0.6 Ohmm) reservoir. Electromagnetic method is chosen to test whether sufficient resistivity differences can be observed via surface measurements. The target is a Lower Cretaceous clastic interval located at an approximate depth of 1200 metres.
Forward modelling demonstrates that the expected resistivity changes at reservoir level cannot be resolved with a survey setup of only surface electrical sources and sensors. Therefore a borehole-to-surface technique has been developed, whereby the metal casing of an abandoned production well serves as input electrode. CSEM surveys were acquired in 2014 and 2015 as timelapse baseline and monitor for both Ex and Ey components. Forward modelling indicates that induction effects from metal objects like casings of production wells cannot be ignored in the EM modelling. A shallow observation well was drilled in 2015 to make collection of Ez datasets possible. A new downhole sensor was developed for this purpose. Numerical simulations suggests Ez data is more sensitive to the anticipated resistivity changes. Since Ez is two orders of magnitude smaller than the horizontal components, verticality is of great importance to avoid masking the Ez signal by interference from unwanted horizontal components.
Similar acquisition parameters are adopted for 2014 baseline and 2015 monitor surveys to facilitate the comparisons. The repeatability is good, generating comparable response functions. The earth model, retained so far by the inversion algorithm, confirms the main resistivity units seen by the resistivity logs in the calibration well. Incorporation of the metal casings in the EM modelling scheme increases the lateral continuity of inverted resisitivity bodies.
This study is a follow-up of work presented in the 2015 ADIPEC conference. In November 2016 a new acquisition campaign will be undertaken to collect a second Ex – Ey monitor and the first monitor survey for the Ez component. A limited time-lapse test has been performed in spring 2016 to monitor Ez with only 1 source station incorporating the borehole electrode Bo-23.
Practice and Lessons Learned for the Development of Naturally Fractured Carbonate Gas Reservoir in Weiyuan Gas Field of Sichuan Basin, China
Authors: Wan Yujin , Su Yunhe 
Published: November 2016

Abstract
Dengying gas reservoir in Weiyuan Gas Field is classified as a fractured dolomite gas reservoir with extreme low matrix permeability and bottom water. The ultimate gas recovery is only 37% in the wake of 50 years’ exploitation. By integrating core analysis, well logging interpretation and dynamic performance analysis, we investigate the key factors affecting gas recovery. Firstly, fractures are the main pathway both for gas to flow into the wellbore and water to invade into the gas reservoir. Secondly, the great amount of water produced from gas wells boosts liquid loading and therefore increases the additional pressure loss in the borehole dramatically. Thirdly, the trapped gas, isolated in the matrix from intermittent production after watered-out owing to non-uniform water flow through the fractures, could not be recovered. For this reason, some imperative measures should be taken to improve the gas recovery. On the one hand, a reasonable flow rate of the gas well should be optimized for preventing from water invasion and extending water-free production period. On the other hand, dewatering is a practical method to extend the life span of the producing well and to improve the gas recovery.
Innovative Geo-Steering Approach with Reservoir Bed Boundary Mapping Impacts Drilling Performance
Authors: Almusallam Ali A. , Yahya Hany A. , Hamid Ab , Halim Abdul , BinAli Ali N. , Ashraf Omar T. , Ghazzawi Ayman A. , Balka Muhammad S. , Samaroo Rajeev B. , Mohiuddin Mohammed A. , Alatiyyah Ahmed S. 
Published: November 2016

Abstract
Combination of well design practices, geo-steering with neutron-density and multilayer bed boundary mapping tools with a motorized rotary-steerable service (RSS) bottom-hole assembly (BHA) has been successfully used in the Ghawar field to accurately detect multiple formation layers enabling drilling performance improvement and optimized well placement services in challenging carbonate wells. The objective of the work-over program is to establish water-free gas production from the reservoir, especially as the gas-water contact (GWC) rises with on-going production. The Ghawar field is located in the eastern part of Saudi Arabia which contains non-associated gas in the target formation varying greatly in depth from the North and South of the field. The target formation consists of major gas bearing intervals, known as Carbonate Layer A and Carbonate Layer B. The Carbonate Layer-A averages about 120 ft in gross thickness and consists primarily of dolomite capped by anhydrite. The Carbonate Layer-B formation, like the Carbonate Layer-A, consists mainly of dolomites capped by tight anhydritic dolomites.
In addition, these wells are drilled in the minimum horizontal stress directional for the advantages of optimized hydraulic fractures during stimulation phase and thus improved productivity. But these wells are notorious for stuck pipe risks, tripping difficulties and slow drilling penetration rates (ROP) with high shocks and vibrations. These risks are primarily due to geo-mechanical wellbore instability and uncertainty in both GWC depth and reservoir pressures arising from the strategy of drilling through multiple layers. With very low contrast in resistivity and the complex nature of the targeted reservoir, steering with only resistivity contrast using conventional bed boundary techniques would not suffice. Ideally, steering in a single layer of the target formation will eliminate the risks associated with the traditional steering method of passing multiple layers.
Neutron-density combined with a new multilayer bed boundary mapping service were successfully deployed in deep gas Udhailiyah on four different wells. This service provided precise delineation of targeted reservoir layers in addition to giving an estimate of formation dip resulting in faster and more accurate geosteering. Steering effectively in these complex thinly bedded reservoir layers has shown improved drilling and tool reliability indicators, including incremental ROP improvement, zero stuck-pipe incidents, stick-slip and shock reduction, and the confidence to push with maximum parameters with a motorized RSS BHA to minimize open hole exposure and avoid borehole deterioration effects with time.
Successful Application of Wireless Bottomhole Data Transmission in the UAE—Bringing Certainty During Well Test Operations
Authors: Mustafa H. , Al Shateri A. A. , Kuliyev M. U. , Kutty S. M. , Chitre S. N. , Al-Marzooqi A. M. , Iabbassen N. , Cesetti M. , Baslaib A. , Hollaender F. 
Published: November 2016

Abstract
As part of ongoing efforts to develop greater gas and oil resources in the UAE, appraisal of several fields discovered decades ago accelerated in 2015 and 2016. Drill stem tests (DSTs) during appraisal are of particular importance; the production and reservoir data gathered during DSTs help determine commercial viability and support the planning of field development and facilities design. Abu Dhabi Marine Operating Company (ADMA-OPCO) was looking for a solution that allows continuous real-time monitoring and well performance evaluation and ensures that test objectives are being met, thus optimizing the test program for best operational efficiency.
A wireless acoustic telemetry system was chosen and successfully deployed for the first time in several ADMA-OPCO projects to provide surface readout of bottomhole gauge data and two-way communication control of tools, such as test valves, fluid samplers, and perforating guns. With the telemetry system, bottomhole data was rendered available throughout operations, from run-in-hole to well killing operations, and was transmitted along with surface measurements to a data repository that was concurrently accessible to operating company engineers as well as the service company support personnel. The availability of real-time bottomhole pressure and temperature readings at the rig and to offsite engineers for analysis and in-time decision-making ensured that tests were executed in the safest and most efficient way while also maximizing the value of information gathered.
Real-time transmission of test data enabled early diagnostic assessment of reservoir behavior and performance and identified deviations from expected responses as they developed. For example, the expected well response following matrix acid stimulation could be estimated from early prestimulation data, even when the well did not actually achieve stable flow to surface. These early diagnostic data helped to justify running stimulation operations and provided a first reasonable estimate of target rates during the main test sequences as well as the opportunity to continuously update the test plan.
The data available for monitoring and initial interpretation during operations was of equal quality to that gathered by memory pressure recorders, and the use of a flexible data transmission plan focusing on key test sequences provided a descriptive capability equal to that conventionally available only after test completion.
The deployment of surface readout of downhole data combined with real-time data transmission and remote support was performed for the first time in the UAE during those appraisal tests and has since become a standard practice as a result of the operational benefits achieved as well as the enhanced interpretability of data gathered.