Co-produced water re-injection is a mature recovery technique for oil fields. Co-produced water that is not re-injected is the largest wastage stream in the oil industry. Handling, treatment and management (especially re-injection back into the reservoir) is an expensive operation. PWRI is a secondary oil recovery method with a small recovery factor in the range of 15-25% and contributes to many surface and subsurface issues, e.g., scaling and reservoir plugging, resulting in the decline of water injectivity, and thus lower oil recovery. This reduction, of course, impinges significantly on the revenue stream of major oil corporations. However, low-salinity (LowSal) water injection is an emerging method that boosts oil recovery by reducing the downsides of produced water re-injection. Using forward osmosis to produce low-salinity water for injection is a novel idea, in which the co-produced water will be the draw solution. In this concept, low-salinity water from water wells (brackish water) is used as the feed to dilute the co-produced water. The diluted co-produced water will then be re-injected as LowSal water. The obviously cheaper alternative of direct dilution of the co-produced water with the brackish water might not produce a water compatible with the oil reservoir in both ionic composition and strength. Data have been collected from different oil fields with various co-produced water and formation characteristics. Different co-produced water treatments were observed in each oil field due to differences in co-produced water chemistry. The water sample for analysis was taken at the skim tanks prior to the water injection stage. A theoretical resistance-in-series model for the forward osmosis stage is presented, which has been adapted from the literature, which incorporates the mass transfer equations, in which the boundary layer and thin-film theory for the membrane intrinsic layers are integrated. An improved shell mass transfer correlation is introduced in addition to the incorporation of a modified reflection coefficient into the resistance-in-series model. The collected data were then incorporated into the theoretical model to calculate and evaluate the forward osmosis performance and, in turn, the water chemistry before re-injection. A forward osmosis rig has been erected to use the latest hollow fibre membrane supplied by the Toyobo Company (Japan). Water and solute flux were measured to validate the model estimations. The model estimated results were at 95% confidence to the measured values. Analytical investigations (ion analysis) for the membrane filtrate at various flowrates and applied pressures were performed to determine the forward osmosis filtrate ion composition. The FO filtrate compositions were then simulated using ScaleChem studio software from OLI for scaling tendency. The software predicted a remarkable reduction in the scaling tendency in the injection water infrastructure (including the oil reservoir) and by more than 50% compared to conventional co-produced water re-injection. Parallel to the ScaleChem predictions, the FO filtrate water was experimentally investigated for scaling using the Differential Scaling Loop rig, in a third-party lab. The DSL results are in good agreement with the ScaleChem predictions. The experimental scaling tendency results show that the injection of forward osmosis filtrate has the minimum occurrence of scaling both in the surface and subsurface. This new concept to produce LowSal produced water re-injection has the potential to improve oil recovery by minimizing the oil reservoir plugging due to scaling.

Crude oil is arguably one of the most complex organic mixture in nature. Therefore, crude oil characterisation requires the use of high resolution and high mass accuracy mass spectrometer such as FT-ICR MS; needed to resolve thousands of ions and assign their elemental formulae. Different heteroatom containing compounds classes are present in crude oil such as N1, S1 and O2 containing compounds. These compounds cause variety of different problems such as N containing compounds cause catalyst deactivation for processes such as hydrodesulfurisation. The choice of the ionisation technique and its polarity is critical to the type of compounds that are observed in a crude oil mass spectrum. Two main studies for crude oil samples are covered in this thesis. The first is crude oil-1, 2 and 3 characterisation using ESI and APPI. The second is structural elucidation of nitrogen containing compounds in crude oil-2. Positive ion ESI FT-ICR MS ionises basic molecules in crude oils. In the literature crude oil samples are dissolved using different ratios of toluene:methanol. The effect of using different solvent composition is often not regarded as important factor to consider. One of the reasons is the addition of ionisation enhancing additive such as formic acid, thought to normalise the ionisation response across different sample solvent composition. However, the solvent composition study data show that different toluene:methanol ratios play a critical role on the ionisation response of nitrogen containing compounds in different crude oils even with the addition of formic acid. Three different ratios were used which are toluene:methanol solvent ratios of 1:9, 3:7 and 6:4 with and without the addition of 0.1% formic acid for the analysis of crude oil-1, 2 and 3. The highest ionisation for N1 containing compounds are achieved through using toluene:methanol ratio of 1:9 with 0.1% formic acid. Further to this the increase of toluene content in the sample solvent decreased the ionisation of N1 containing compounds in the analysed crude oils even with the addition of formic acid. However, the rate of decrease in the ionisation of N1 containing compounds is more significant for crude oil-1 and 2 compared to crude oil-3. Thus, comparing nitrogen containing compounds among different crude oils should be undertaken using the solvent composition, toluene:methanol ratio of 1:9 with 0.1% formic acid. Another aspect for the solvent composition study is that multimer formation is not only concentration driven but as well sample solvent composition dependent. The data showed that multimer formation in N1 DBE versus carbon number plots are reduced with acid addition and methanol content increase in the sample solvent. The use of positive ion ESI allowed the ionisation of basic compounds in crude oil-1, 2 and 3. To ionise non-polar classes such as aromatics and thiophene containing compounds in crude oil-1, 2 and 3 positive ion APPI is used. Aromatics and thiophene were the most abundant ions in crude oil-1, 2 and 3 mass spectra. No significant difference in ion intensities for these ions were observed for crude oil-1, 2 and 3 mass spectra. However, the use of negative ion APPI showed major differences in the ions intensities of crude oil-1, 2 and 3 regarding HC, HC-R, N1, S1 and S1-R classes. Further, comparable data for the O2 class were obtained using negative ion ESI and APPI Orbitrap MS for crude oil-1, 2 and 3. Thus, negative ion APPI Orbitrap MS can be used to compare the O2 class relative abundance among different crude oils. Further to the characterisation study, structural elucidation of nitrogen containing compounds in crude oil-2 using positive ion ESI FT-ICR MS/MS was undertaken. Understanding the chemical structure might have applications in designing more effective catalysts for HDN process. At first a method development approach was undertaken to reduce the analysis time to 4.5 min and increase detection of low m/z low intensity fragment ions. This aim was achieved through increasing the ion accumulation time from 0.05 s to 5 s with averaging 40 spectra. Different N1 precursor ions were isolated at different DBE values and degree of alkylation. A collision energy of 60 V was required to observe characteristic fragment ions such as N expulsion for N1 precursor ion with DBE value of 13.5. While for N1 precursor ion at DBE value of 6.5 a CE 40 V was enough to observe characteristic fragment ions. However, different approach was used for N1 precursor ion with low DBE values, isolating the precursor ion with the lowest degree of alkylation. This approach was essential to observe N expulsion fragment ions for N1 precursor ion with DBE value of 6.5. The core aromatic structure for N1 precursor ions from DBE values of 3.5 to 10.5 were suggested. This suggestion was based on N expulsion fragment ion and the dealkylated fragment ion. Furthermore, N expulsion from the aromatic ring supports the postulation that the nitrogen in the various precursor ions discussed is pyridinic. This was further confirmed for N1 precursor ion with DBE value of 6.5 using a model compound, 2-butlyquinoline.

This thesis starts with a conceptual exploration of the challenges in the management of Petroleum Pipeline Rights of Way (ROW), within the context of public infrastructure management. Upon this basis, a holistic understanding has been developed of the concept. This understanding argues the need for Collaboration-Based Management of ROW for Petroleum Pipelines, in particular, involving the communities traversed by the pipelines as stakeholders, in order to enhance long term social, economic and environmental sustainability through their interaction with the other stakeholders: the government and multi-national oil companies. Building upon the theoretical arguments developed, this research has proposed a geographic information system framework for demarcating ROW that is capable of continuous updating in line with new knowledge. By applying this framework, the ROW in the Federal Capital Territory, Abuja, is demarcated; and further analysis is applied that shows widespread encroachment on the ROW by other land uses. A total of 588 structured interview questionnaires were completed, five focus group discussions held and 14 key informant interviews conducted across four case study areas. Analysis of the data revealed that the pipeline project has not improved the economic situation of the people in the communities it traverses. The empirical evidence from the case studies also suggests that vandalism thrives in the pipeline communities, because those geographically closest to the pipeline have no role in its management and the national and multi-national oil companies that have lawful authorisation over the pipelines and the associated ROW do not have the capacity to maintain real-time surveillance. Hence, there is a need for a new approach, based on a collaboration-based framework. This framework will engender the adoption of local knowledge and experience regarding the environment for the greater collective interest of the oil and gas industry, the citizenry and, by extension, the Nigerian national economy.

No description available.

This study provides new insights into the transient uid ow dynamics that characterise high temperature hydrothermal systems. So far, these kind of studies have used process models that tend to over-simplify the geology and focus instead on the physical processes, hence not revealing the hidden behaviour that depends on the complex geological structures often encountered in hydrothermal systems. This study is one of the rst examples where high resolution numerical simulations in two and three dimensions have been applied to hydrothermal systems in order to preserve geological detail in the models explicitly. Two prime examples in Iceland for seismicity-induced uid ow and groundwater ow during volcanic eruptions, respectively, have been selected for this purpose. The rst example is the Tjörnes Fracture Zone, a heavily faulted transform zone o shore in North Iceland where most of the Icelandic earthquakes occur. The work demonstrated that a moderate permeability contrast between the shallow sedimentary basins and deep crustal basement causes two distinct uid ow regimes which are only connected during a seismic event. When such an event occurs, faults in the Tjörnes Fracture Zone in ate and connect the two uid ow systems, causing hot uids migrating from the basement into the basins at extreme ow rates. This explains key geochemical observations made in the Tjörnes Fracture Zone before and after a seismic event. The second study investigated the 1874 to 1875 volcano-tectonic episode at the Askja volcano, which is the third largest silicic eruption since settlement in Iceland. Here it was demonstrated how syn-eruptive groundwater ow inside the Askja caldera changed the eruptive style of the March 1875 eruption, causing a well-documented change from a wet to dry eruptive style. The results of this work provide some fundamental new insights into the transient dynamics of uid ow in active high temperature hydrothermal systems and suggest that these kind of simulations may be used to complement studies assessing the risk and hazard of future volcanic eruptions and seismic events.

The production of acidic or sometimes heavier crudes often leads to the formation of either calcium naphthenate or sodium carboxylate soap emulsions during oil production operations. This problem has been recognised as a major flow assurance problem in the oil industry. In this work, both harder calcium naphthenates and more emulsion–like sodium carboxylates have been studied and these are viewed as “end members” in the spectrum of field naphthenate deposits which may occur. In this thesis, four related aspects of naphthenate deposits are studied, as follows: (i) Characterization of various field naphthenates samples from different parts of the world, involving naphthenic acid extraction method development and subsequent extract analysis using electrospray mass spectrometry (ESMS) and atmospheric pressure chemical ionisation mass spectrometry (APCI MS) techniques. It was observed that different naphthenic acid extraction and analysis methods affected the naphthenic acid identification and apparent composition; (ii) Geochemical studies have been carried out on various crude oils which form calcium naphthenate deposits, sodium carboxylate soaps and emulsions. Biomarker correlation analysis was employed on the aliphatic and aromatic fractions of the crude oil samples using gas chromatography (GC) and gas chromatography mass spectroscopy (GCMS); (iii) Thermodynamic modelling of naphthenate formation was carried out, and both a simple thermodynamic pH change naphthenate model and a full naphthenate precipitation model have been developed. This thermodynamic model describes the chemistry of a simple partitioning “pseudo” naphthenic acid which may form calcium naphthenate “precipitate”, according to a solubility product type description. This model has been used in a wide sensitivity study which makes some predictions about the way a precipitating Ca-Naphthenate (CaN) system behaves and these predictions have been confirmed experimentally; (iv) Naphthenate chemical inhibition studies have been performed in order to develop a methodology for the mitigation of these deposits. Static “inhibition efficiency” tests have been conducted using 8 different naphthenate inhibitors in order to determine the most appropriate methodology for testing and also the effectiveness of these chemicals in preventing the formation of calcium naphthenates and sodium carboxylate soap emulsions.

North Oman is underlain by Cretaceous Natih and Shuaiba carbonates, which are important hydrocarbon reservoirs. Fracturing, especially fracture clusters, contributes significantly to reservoir performance. The fractures in the Natih are strongly affected by mechanical layering, whereas the Shuaiba is less obviously layered, except in the NW, where Upper Shuaiba is present. The fracture network of the Lower Shuaiba in the central and SE region of north Oman is dominated by fault–related fractures and associated corridors. Late Cretaceous deformation created NW-WNW strike-slip faults and associated fractures, as well as activation of salt diapirs. Tertiary deformation (NE shortening) resulted in the creation of abundant NE oriented background fractures, and more importantly NE fracture corridors that act as conduits to flow. Salt diapirs, when reactivated during Tertiary events, result in more intense fracturing locally. Field scale analyses of the fracture networks for Ghaba North and Lekhwair A North (both Shuaiba), based on BHI logs, reveal a change in dominant fracture orientation between the SE and the NW parts of north Oman. The NE fracture corridors play a major role in connecting the NW-WNW fractures seen in Lekhwair A North, and the current NE oriented maximum horizontal stress may also play a role.

This PhD thesis presents a laboratory study aiming at a better understanding of the stress-strain response of the Vosges sandstone (porous rock) tested at a range of confining pressures (i.e., 20-190 MPa) and different axial strain levels. Localised deformation was captured at different scales by a combination of full-field experimental methods, including Ultrasonic Tomography (2D), Acoustic Emissions (3D), X-ray Tomography (3D), and 3D volumetric Digital Image Correlation, plus thin section and Scanning Electron Microscope observations (2D). These experimental methods were performed before, during and after a number of triaxial compression tests. The combined use of the experimental techniques, which have different sensitivity and resolution, described the processes of shear band and shear-enhanced compaction band generation, which formed at low to intermediate and relatively high confining pressures, respectively. Pure compaction bands were not identified. The deformation bands were characterised as zones of localised shear and/or volumetric strain and were captured by the experimental methods as features of low ultrasonic velocities, places of inter- and intra-granular cracking and structures of higher density material. The two main grain-scale mechanisms: grain breakage (damage) and porosity reduction (compaction) were identified in both shear band and shear-enhanced compaction band formation, which presented differences in the proportions of the mechanism and their order of occurrence in time.

History matching of reservoirs is very important in the oil industry because the simulation model is an important tool that can help with management decisions and planning of future production strategies. Nowadays, time-lapse (4D) seismic data is very useful for better capturing the fluid displacement in the reservoir, especially between wells. It is now common to integrate 4D seismic with production data in order to constrain the simulation model to both types of data. This thesis is based on a technique for automatic production and seismic history matching of reservoirs by. This technique integrates various tools such as streamline simulation, parameterization via pilot points and Kriging and geo-body updating, a petro-elastic model and the neighborhood algorithm, all in an automatic framework. All studies in this thesis are applied to the Nelson field but the approaches used here can be applied to any similar field. The history matching aim was to identify shale volumes and their distribution by updating three reservoir properties, net:gross, horizontal and vertical permeability. All history matching studies were performed in a six years production period, with baseline and one monitor seismic survey available, and then a forecast of the following three years was made with a second monitor for comparison. Various challenges are addressed in this thesis. We introduce a streamline guide approach in order to efficiently select the regions in the reservoir that have a strong influence on production activity of the wells and 4D seismic signature. Updating was performed more effectively compared to an approach where parameters were changed everywhere in the vicinity of the wells. Then, three parameter updating schemes are introduced to effectively combine various reservoir parameters in order to capture correctly the flow behaviour. The observed 4D seismic data used in this study consisted of relative pseudo-impedance with a different unit compared to synthetic impedance data. This challenge was addressed by introducing normalization. 4D predictions in the vertical well locations and full field simulation cells used in the normalization study and we observed different level of signal/noise ratio in normalized observed 4D maps at the end of study. We include the normalized 4D maps in history matching of the field and we observed that normalization very important. We also compared the seismic and production history matching studies with a case where seismic was not included in history matching (production history matching). The results show that if 4D data is normalized appropriately, the reduction of both seismic and production misfits is better than the production only history matching case.

AVO (for Amplitude Versus Offset) is a seismic technology known in the oil industry for its ability to differentiate gas sands (over oil producing reservoirs) from wet sands (over non-producing reservoirs) in the Gulf of Mexico. Its applicability to a broad range of exploration fields has led to its potential application within the ADEMA (Advances in Exploration Methods and Applications) project being considered. Within the frame of this project, this PhD thesis assesses the ability of AVO to detect a difference between Mudstone and Sandstone roofs over a 6 meters thick coal seam, in the region of Daw Mill (UK). It moreover presents a modification of a triaxial cell aimed at calibrating AVO in the laboratory, and thereby improving the quality of AVO analysis in general. The analysis presented in this PhD thesis leads to the conclusion that in this region, the particular rock properties can lead to a signal difference detectable by AVO. However, analysis of seismic data confirmed that tuning effect interferes with these distinct signals, and prevents AVO technology to differentiate mudstone from sandstone roofs. Finally, this thesis proposes different technical recommendations for successfully running a test with the modified triaxial cell in future.