Salomone, Andrea (ENI) | Burrafato, Sebastiano (ENI) | Ricci Maccarini, Giorgio (ENI) | Poloni, Roberto (ENI) | Gioia, Valeriano (ENI) | Concas, Antonio (ENI) | Tangen, Geir Ivan (Lundin Norway AS) | Huse, Arve (Lundin Norway AS) | Antoniani, Lucio (NOV) | Andersen, Mats (NOV) | Zainoune, Sanna (NOV)
This paper presents the positive results of the first deployment of wired drill pipe (WDP) technology and along-string measurement (ASM) tools in drilling operations in the Adriatic Sea. The WDP system was used within the frame of a multi-objective testing program, in conjunction with an experimental downhole tool.
The system allowed transmission of real-time, high-density, low-latency data from logging-while- drilling (LWD) tools and from ASM subs. These tools provided temperature, annular/internal pressure, rotation, and vibration data. This was the first time WDP and ASM tools were used by an operator in the Adriatic Sea. The system was also used for activation and communication with another experimental downhole tool on this project.
The high-speed telemetry system made it possible to achieve impressive operational and performance benefits. Annular pressure measured along the string provided a better understanding of the drilling mud condition and behavior along the wellbore, thereby allowing the operator to stay in the safe mud-weight window and helping them to avoid unintentional hole fractures or collapse.
During pumping in and out of hole, swab and surge were also monitored closely with downhole, real- time measurements from the ASM tools. The same effects were controlled after drilling each stand, when the interval drilled was reamed to ensure sufficient hole cleaning.
While drilling, the system raised the rate of penetration (ROP) limit by removing constraints on data acquisition while still providing the confidence that the hole was being cleaned while drilling. Drillstring vibration was recorded as well, and potential benefit in preventing premature failure of downhole tools were highlighted.
The test verified that improved drilling performance was enabled using WDP technology. Awareness of downhole conditions and a substantial reduction in risk were also benefits. In addition, the technology unlocked bidrectional communication and control with modern downhole tools.
Fuxa, Jason (Baker Hughes) | Di Giampaolo, Paolo (Baker Hughes) | Ferrara, Giovanni (ENI) | Di Pietro, Mario (Baker Hughes) | Sportelli, Marco (ENI) | Ripa, Giuseppe (ENI) | Di Campli, Antonio (Baker Hughes)
This paper details a field application of Shaped Memory Polymer (SMP) material for sand management delivering an innovative approach for sand control completions. The use of the technology has enabled profitable exploitation of residual reserves in a mature gas field offshore Adriatic Sea. The paper reviews details of the field deployment, with both economic and well performance results described.
The Barbara Field was discovered in 1971 and 102 wells have been drilled to date. The trap is a very gentle, slightly asymmetrical anticline made by Pleistocene sandy turbidites,sedimented on the underlying carbonate substrate. Methane gas bearing layers have been sealed by several argillaceous intercalations that worked also as the source rocks of this multilayer reservoir. The sandy layers in this Pleistocene sequence, Carola Formation, have thickness ranging from few centimeters up to some meters, and porosity from 22 up to 33%. Isolation of multiple gas-water contacts and fines production have been two crucial issues while producing the field.
Since 2000, all seven Barbara platforms have required workovers by means of performing sidetracks. Due to the reservoir characteristics, the well interventions have been completed with multi-layer, stacked cased-hole sand control completions. Despite a continuous improvement of procedures and technique, the traditional sand control methods have been efficient but were no longer profitable, due to challenging market conditions.
An open-hole completion using SMP combined with zonal isolation and selective production has proved to be an effective alternative to cased-hole sand control. This novel completion approach resulted in a significant reduction in both cost and rig time. It is estimated that nearly two weeks of rig time was saved and an overall workover cost reduction of approximately 35%, with further efficiencies to be realized on upcoming deployments. To date, the completion has proved to be an effective sand control method, with no produced solids, no plugging effect, and gas production that has met expectations.
During this period, a series of emerging innovations would find commercial success and reshape the upstream industry into the 21st century.Source: SPE. You have access to this full article to experience the outstanding content available to SPE members and JPT subscribers. To ensure continued access to JPT's content, please Sign In, JOIN SPE, or Subscribe to JPT Contrary to popular imagination, which favors John Wayne stereotypes heroically rescuing the oil industry with wrench and hammer, the oilfield is a place of exquisite engineering, the match of anything on Earth, a marvel of innovation at the biggest and smallest scales. The office-block sized blowout preventers on the ocean floor or the minute geopositioning electronics inside a logging while drilling (LWD) tool both are designed to operate perfectly within exacting environmental specifications. Almost every aspect of upstream exploitation is the result of exhaustively leveraging the glorious value chain of math, science, and engineering.
Mohammadzadeh, Omid (Schlumberger-Doll Research Center) | Taylor, Shawn D. (Schlumberger-Doll Research Center) | Eskin, Dmitry (Schlumberger-Doll Research Center) | Ratulowski, John (Schlumberger-Doll Research Center)
One of the complex processes of permeability impairment in porous media, especially in the near-wellbore region, is asphaltene-induced formation damage. During production, asphaltene particles precipitate out of the bulk fluid phase because of pressure drop, which might result in permeability reduction caused by both deposition of asphaltene nanoparticles on porous-medium surfaces and clogging of pore throats by larger asphaltene agglomerates. Experimental data will be used to identify the parameters of an impairment model being developed. As part of a larger effort to identify key mechanisms of asphaltene deposition in porous media and develop a model for asphaltene impairment by pressure depletion, this paper focuses on a systematic design and execution of an experimental study of asphaltene-related permeability damage caused by live-oil depressurization along the length of a flow system.
An experiment was performed using a custom-designed 60-ft slimtube-coil assembly packed with silica sands to a permeability of 55 md. The customized design included a number of pressure gauges at regular intervals along the coil length, which enabled real-time measurement of the fluid-pressure profile across the full length of the slimtube coil. The test was performed on a well-characterized recombined live oil from the Gulf of Mexico (GOM) that is a known problematic asphaltenic oil. Under a constant differential pressure, the injection flow rate of the live oil through the slimtube coil decreased over time as the porous medium became impaired. During the impairment stage, samples of the produced oil were collected on a regular basis for asphaltene-content measurement. After more than 1 month, the impairment test was terminated; the live oil was purged from the slimtube coil with helium at a pressure above the asphaltene-onset pressure (AOP); and the entire system was gently depressurized to bring the coil to atmospheric conditions while preserving the asphaltene-damaged zones of the coil. The permeability and porosity of the porous medium changed because of asphaltene impairment that was triggered by pressure depletion. Results indicated that the coil permeability was impaired by approximately 32% because of pressure depletion below the AOP, with most of the damage occurring in the latter section of the tube, which operated entirely below the AOP. Post-analytical studies indicated lower asphaltene content of the produced-oil samples compared with the injecting fluid. The distribution of asphaltene deposits along the length of the coil was determined by cutting the slimtube coil into 2- to 3-ft-long sections and using solvent extraction to collect the asphaltenes in each section. The extraction results confirmed that the observed permeability impairment was indeed caused by asphaltene deposition in the middle and latter sections of the coil, where the pressure was less than the AOP. With the success of this experiment, the same detailed analysis can be extended to a series of experiments to determine the effects of different key parameters on pressure-induced asphaltene impairment, including flow rate, wettability, and permeability.
Mohammadzadeh, Omid (Schlumberger-Doll Research Center) | Taylor, Shawn David (Schlumberger-Doll Research Center) | Eskin, Dmitry (Schlumberger-Doll Research Center) | Ratulowski, John (Schlumberger-Doll Research Center)
One of the complex processes of permeability impairment in porous media, especially in the near wellbore region, is asphaltene-induced formation damage. During production, asphaltene particles precipitate out of the bulk fluid phase due to pressure drop, which may result in permeability reduction due to both deposition of asphaltene nanoparticles on porous medium surfaces and clogging of pore throats by larger asphaltene agglomerates. Experimental data will be used for identification of parameters of an impairment model being developed. As part of a larger effort to identify key mechanisms of asphaltene deposition in porous media and develop an asphaltene impairment model, this paper focuses on a systematic experimental study of asphaltene-related permeability damage due to live oil depressurization along the length of a flow system.
An experiment was performed using a custom-designed 60-ft slimtube coil assembly packed with silica sands to a permeability of 55 mD. The custom design included a number of pressure gauges at regular intervals along the coil length which enabled real-time measurement of the fluid pressure profile across the full length of the slimtube coil. Test was performed on a well-characterized recombined live oil from the Gulf of Mexico that is a known problematic asphaltenic oil. After saturating the slimtube coil with stock tank oil (STO) to restore wettability and attain the initial state of the test, the STO was then gradually displaced by flooding at least 3 pore volumes of live oil above the asphaltene onset precipitation (AOP) pressure. The impairment portion of the experiment was then initiated by maintaining initial pressure at the inlet while the outlet pressure was regulated slightly above the saturation pressure. Under this constant differential pressure, the injection flow rate through the slimtube decreased over time as the porous medium became impaired. During the impairment stage, samples of the produced oil were collected on a regular basis for asphaltene content measurement. After more than a month, the impairment test was terminated, and the live oil was purged from the slimtube coil with helium at a pressure above AOP pressure, and then the whole system was gently depressurized to bring the coil to atmospheric conditions while preserving the asphaltene damaged zones of the coil. Changes in permeability and porosity of the porous medium were obtained due to asphaltene impairment caused by pressure depletion.
Results indicated that the coil permeability was impaired by about 32% due to pressure depletion below AOP pressure, with most of the damage occurring in the latter section of the tube which operated entirely below the AOP pressure. Post analytical studies indicated lower asphaltene content of the produced oil samples compared to the injecting fluid. Asphaltene deposition distribution along the length of the coil was determined by cutting the slimtube coil into 2 to 3 ft long sections and using solvent extraction to collect the asphaltenes in each section. The extraction results confirmed that the observed permeability impairment was indeed due to asphaltene deposition in the middle and latter sections of the coil, where the pressure was below the AOP pressure.
Lawal, Kazeem A. (First Exploration & Petroleum Development Company) | Ukaonu, Cyril E. (First Exploration & Petroleum Development Company) | Ovuru, Mathilda I. (First Exploration & Petroleum Development Company) | Eyitayo, Stella I. (First Exploration & Petroleum Development Company) | Matemilola, Saka (First Exploration & Petroleum Development Company)
Electrofacies modelling, which includes identification and grouping, is a critical part of reservoir characterisation. Because it governs the estimation and distribution of key rock and rock-fluid properties, the electrofacies model, to a large extent ((if augmented with core-derived information), determines the quality of static and dynamic reservoir models. Unfortunately, owing to the lack of a universally acceptable method, the outcome of electrofacies modelling is not always unique. This explains the usual difficulty in achieving a meaningful comparison of different reservoirs or correlating different packages, even with the same set of well logs.
To address the problem, this paper presents a set of mathematical models and simple workflows for quantitative characterisation and grouping of electrofacies in shaly sandstone formations. The gamma ray, density, and neutron, which are commonly available lithology-indicating and absolute-value reading logs, are integrated to define a quantity called composite shaliness parameter. The use of a simple scaling rule ensures that the values of the shaliness parameter are limited to the 0 - 100% range. To make the model universally applicable, the scaling of the shaliness parameter covers the ranges of values of the indicated logs in most shaly sandstone formations.
Although the models and workflow are intended to be universally applicable to all shaly sands to enable global benchmarking of formations as may be necessary, provision is made for local applications. In the latter cases, a simple procedure for adapting the scaling rule to specific local problems is presented.
Using field examples from the Niger Delta, the validity of the proposed method is examined. It is evaluated against mobility tests, core analysis and spectral gamma-ray log, which are techniques known for better reservoir characterisation at different scales. It is found that the results of the proposed method are in satisfactory agreement with findings from these reference characterisation techniques.
Bartelucci, P. (Eni S.p.A.) | Borghi, M. (Eni S.p.A.) | Crottini, A. (Eni S.p.A.) | Galli, G. (Eni S.p.A.) | Pirrone, M. (Eni S.p.A.) | Rizzo, G. (Eni S.p.A.) | Nardiello, R. (Baker Hughes Inc. ) | Chace, D. (Baker Hughes Inc. ) | Kim, Y. (Baker Hughes Inc. ) | Zhang, Q. (Baker Hughes Inc. )
This paper presents a cased hole methodology for gas density and pressure calculation to quantify the gas depressurization in mature gas fields by use of Pulsed Neutron technology. The approach is based on an advanced interpretation of gas saturation behind casing and utilizes Monte Carlo reservoir characterization models based on different gas density responses.
The field application refers to an onshore multi-layer sand reservoir in the eastern Pianura Padana Basin producing biogenic gas since 1971. A strong decline of static bottom hole pressure (SBHP) has been recorded during the field life. The pressure drop is not constant and/or equal across the field gas levels and it may vary a lot between them. In many cases, the pressure of the single layers cannot be measured since two or more layers are completed to the same casing string.
The following proposed methodology allowed to quantify the different depletion degree of the main field levels for reservoir management and production optimization purposes. The first step of the analysis is to calculate the current reservoir gas saturation using commercial pulsed neutron ratio-based measurements. The following pressure depletion analysis could be applied if the original water saturation is unchanged and only a pressure drop has occurred. Capture Cross Section (Sigma) analysis is relatively insensitive to pressure depletion, but it can be used with confidence to confirm that the original water saturation has not changed. Assuming unchanged the open hole reservoir conditions in terms of reservoir saturation and pressure, if the current ratio derived gas saturation excesses the open hole saturation, then the gas density is iteratively reduced and the calculation repeated using new modeled responses. Depleted gas density and related reservoir pressure are finally determined when calculated cased hole gas saturation matches the original open hole gas saturation.
In response to the Macondo disaster, the EU published Directive 2013/30/EU on the Safety of Offshore O&G Operations. The transposing legislation serves to implement a Major Accident Hazard control (Safety Case) regime, similar to that which has been in place in the North Sea since the Piper Alpha disaster in July 1988. Such Safety Case regimes, based broadly on that introduced in the UK North Sea following the Piper Alpha disaster, are aimed at preventing the (re)occurrence of Major Accidents in the Offshore O&G sector and reducing their consequences, should they occur. Ultimately, the objective is to have a regime in place, which is effective in reducing the risk associated with Major Accidents across Europe. The legislation places requirements on both the industry operators and the regulators. Whilst preventative arrangements can be operator and local asset specific (but aligning to industry best practice and the Directive/Legislation requirements), given the transboundary nature of potential consequences (e.g. major oil spill affecting highly sensitive environments) a more integrated, regional approach is required.
Almost all countries in the Mediterranean region have some form of offshore O&G operations and clearly, the situation is complex as not all form part of the EU. At the same time, the socio-economic and environmental sensitivities of the Mediterranean Sea are well recognised. This paper outlines the challenging steps of the implementation status of the Safety Directive across EU on the basis of experience & lessons learned by the Authors in assisting O&G Companies across several countries bordering the Mediterranean Sea. The aim of the Paper is to present a Regional overview across the countries involved (EU, not EU, Accession EU) examining future trends for a sustainable development.
Following the Macondo disaster, a range of changes have been implemented in relation to how Major Accident Hazards (MAHs) are controlled. From a European context, most notable has been the issue and subsequent transposition into local legislation of the European Union (EU) Directive on the Safety of Offshore Oil and Gas Operations (Directive 2013/30/EU).