Pore pressure and gas saturation distribution in sedimentary basins are difficult to predict and quantify because these two factors produce the same impact on reducing P-wave velocity (Vp). To tackle this issue, the modified Eaton's equation for Vp and S-wave velocity (Vs) ratio derived from automatic velocity analysis and a pre-stack inversion was applied to estimate pore pressure distribution, and

The fluvial sandbodies from river channels with different patterns have remarkable heterogeneities. This study suggests that the pattern of river channel controls on the sandbody stacking pattern, resulting in the heterogeneities of physical properties of sandstone reservoirs. The study area is located in the Gaomiaozi and Zhongjiang areas of western Sichuan depression in China. Based on the observation

Field development and control optimization aim to maximize the economic profit of oil and gas production while respecting various constraints such as production limits imposed by the available fluid processing capacity and/or reservoir management strategies. The limitations of the existing optimization workflows are 1) well locations or production/injection controls are optimized independently despite

Quantifying and analyzing the geological uncertainties associated with the geostatistical models is critical to design a reliable production strategy. A large number, hundreds, even thousands, of model realizations should be run in a reservoir simulator to quantify the uncertainties in terms of a target flow response. However, this becomes a time consuming and computationally demanding process. In

Presenting a predictive model through handling of the dynamical system is critical for modern technologies and industrial application. Here, Hankel-based dynamic mode decomposition is used to generate a predictive model for the slug flow regime. The flow dynamics are disintegrated into linear and nonlinear parts, the latter of which is responsible for intermittency phenomena. The proposed model shows

The economic and efficient development of petroleum resources can be realized by dynamically adjusting the reservoir development scheme for the sake of higher recovery efficiency with low development cost. As an important part of the closed-loop reservoir management (CLRM), production optimization has gained increasing research interests. A number of sophisticated production optimization techniques

The purpose of this study was to determine the three-phase saturation (water; gas hydrate, GH; and gas) in real time to gain insights into the GH depressurization process. Although X-ray computed tomography (CT) can be used to investigate the density changes in the GH core during the depressurization experiment, it is hard to distinguish between water and GH due to their similar densities and the limited

Alluvial fan reservoirs associated with episodic flood flows are generally heterogeneous, both laterally and vertically, owing to the variable depositional conditions and mechanisms. The complexity of sedimentary processes results in distinct challenges in terms of reservoir characterization and subsurface modelling. The ability to discern fan deposits in the subsurface directly impacts the assessment

Polycrystalline diamond compact (PDC) cutter is the key component of a drill bit. Recently the shaped PDC cutters, especially the axe-shaped cutter (ASC), have been warmly welcomed by the drilling engineers. However, the rock-breaking mechanism of ASC is rarely studied. In order to investigate the cutting action of ASC, comparative experiments of ASC and conventional cylinder-shaped cutter were carried

Paper describes the challenges and forward developments to face up on Operation and Maintenance (O&M) issues at the Johan Sverdrup field (Blocks: PL 501, PL 265 and PL 502), on the phases (Concept and Design, Construction and Hook-up, Commissioning, Operations and Maintenance, and Recycling), and a research study of the Oil&Gas profitability. Estimated reserves are between 1.8 billion to 2.8 billion

Higher fluid loss volumes and suspension capability are the critical shortcomings of water-based muds. It can promote problems during drilling operations. The rheological and filtration properties of all drilling muds have been continually considered the essential characteristics for a successful drilling operation. Various irreversible problems are directly associated with drilling fluids rheological

For high temperature reservoirs, solid particle foaming stabilizers were commonly used to improve the long-term stability of foam because they were not sensitive to temperature and salinity. Solid particles which could only be dispersed in the solution were easy to agglomerate and sink, and as a result, they could reduce the foaming effect. Consequently, it is necessary to modify the solid particles

Observed deviations from classical diffusion (specifically transient linear flow, TLF) for Permian Basin Wolfcamp shale oil wells have been historically attributed to reservoir geometric heterogeneity and consequent anomalous diffusion (AD). Recently, we have suggested that the combination of multiphase flow and variable operating conditions could create similar reservoir signatures (as quantified

This study deciphers the origin and distribution of multiphase carbonate cementations and assesses their implications for reservoir quality of the Eocene delta hydrocarbon sandstones in the Bohai Bay Basin. Petrographic observation and stable isotopic analysis identified two phases of carbonate cementations: (1) eodiagenetic phase including non-ferroan calcite cement precipitated at 25–42 °C (δ13CVPDB:

Chloride salts of NaCl, KCl, CaCl2, and MgCl2 are among the essential salts examined for enhanced oil recovery (EOR) purposes through chemical injection, low salinity injection, smart water injection, etc. These salts are crucial for EOR studies since they exist in the reservoir with undeniable effects on interfacial tension (IFT), wettability alteration, etc. The alkaline injection that can produce

Plug and abandonment (P&A) operations prevent oil and gas leakages from hydrocarbon zones to different formations, freshwater underground resources, and the surface. Cement plugs that are used in P&A operations play a crucial role in impeding reservoir fluid migrations. The dump bailing method is one of the common methods of the cement plug placement in which a determined volume of cement is dumped

Inflow control device (ICD) restricts flows of certain sections to achieve a uniform push of water oil contact along a horizontal well. The efficiency of ICD depends on its configuration (location, number of nozzles, and nozzle sizes). Traditionally, optimal ICD configurations have been selected using a trial and error approach simulating different configurations. This method is time-consuming and

A low-order two-phase dynamic flow model for drilling operations with gas kick is developed. The purpose is to enable fast and robust simulation of the behavior and propagation of influx gas in the bore hole, and the effects it has on the total flow dynamics. The model handles both open and closed wells, as well as the full range of pump rates and gas influx rates that are likely to occur in drilling

Existing shear-wave velocity prediction methods for organic-rich rocks have not simultaneously taken the effects of organic matter (kerogen) distribution and pore shape on the velocity into consideration. To solve this problem, the current paper proposes a shear-wave velocity prediction method for organic-rich rocks based on the Kuster–Toksöz (KT) rock physics model and chaotic quantum particle swarm

Many fluids used in petroleum and chemical industries are generally described as complex systems that exhibit time-independent non-Newtonian behavior. To adequately represent the rheological behavior of an oil-tolerant and salt-resistant aqueous foam system, a Carreau-Extended (Carreau-E) rheological model, which includes a yield stress, a shear-thinning parameter and a time constant, has been established

Well construction, well abandonment and restoration of well integrity are the reasons at a broad level why cementing jobs are performed. During well construction phase, the primary objective of cementing job is to replace the drilling mud in the annulus with pure cement. Intermixing of the drilling mud and the cement slurry produces unpumpable mixture, especially in the case of OBM. As literature review

The pre-crosslinked gel particles has been perceived as an important alternative to improve oil recovery from fractured-vuggy carbonate reservoirs. However, it remains a great challenge for the applications in high temperature and high salinity reservoirs. In this context, we firstly developed novel preformed gel particles with controllable density (PGPCD) which can be used at high temperature (140

The cyclic gas injection technique is widely used in the development of condensate gas reservoirs. However, the override of injected gas induces severe gravity segregation in formations, thereby substantially limiting the application of this technique. At present, few literatures have been found to illustrate the override phenomenon taking place between gases. In this study, experiments were performed

The nonuniformity of the steam chamber has a significant influence on oil recovery in the process of Steam-Assisted Gravity Drainage (SAGD). To improve steam conformance, Flow Control Devices (FCDs) are generally installed in both the SAGD injector and producer. In this paper, we investigated the steam conformance of tubing-deployed FCDs in a SAGD well pair. First, a three-phase, three-dimensional

Welan gum (WLG) has been reported being used in chemical flooding and hydraulic fracturing for high-temperature and high-salinity reservoir development due to its good temperature resistance and salt tolerance properties. The adsorption and retention of WLG in reservoir rocks will reduce the reservoir permeability and affect the economic development of oil and gas fields. However, there are no reports

A first and detailed study of the geochemistry and mineralogy characterizing the North Sea reservoir and non-reservoir chalk is provided in this work. The study is based on 185 cores from exploration and development wells in the North Sea. The cores related to reservoir development have different flooding status – unflooded or waterflooded at various temperatures – and are directly sampled from the

To date, the modeling method of point bar internal architecture has still not been fully developed. Traditional methods for point bar architecture modeling usually require a finer mesh, which is more expensive computationally, and upscaling the model can possibly generate a misleading model. The above restricts the industrial application of the architecture model to just oilfield development. Therefore

Axial ultra-high frequency vibration (UHFV)-assisted drilling technology that combines polycrystalline diamond compact bits and rotary ultrasonic machining technology is expected to improve rock-breaking efficiency and reduce the drilling costs of deep and ultra-deep wells. To better understand the rock-breaking mechanism under a UHFV load and provide a theoretical basis for practical engineering,

Colloidal gas aphrons (CGA) drilling fluid has been worldwide used in drilling depleted reservoirs and other under-pressured zones for its special plugging mechanism and excellent ability of lost circulation control. However, the research temperature of CGA system reported in the previous literatures is within 140 °C, and it is still an urgent challenge to promote its application in high-temperature

Well logging is a significant method of formation description and resource assessment in exploration and development of oil, natural gas, minerals, groundwater, and sub-surface thermal energy, as well as geotechnical engineering and environmental research. However, the shortage problem of well logging data always exists because well logs can only be measured through a drilling process involving costly

Mineral scaling issues have been reported in many alkaline and Alkaline-Surfactant-Polymer (ASP) projects. The role of the in situ mineral reactions on the produced scaling ions and pH has been little reported in the literature. The objective of this study is to investigate the impact of the in situ chemical and geochemical interactions on the scale precipitation risk when the fluids reach the wellbore

Halite cementation is a major exploration risk in hydrocarbon reservoirs. Halite-cemented reservoir zones are characterized by extremely low porosity and permeability due to partial or complete occlusion of the pore space. Despite being a key process that affects the quality of the productive formation, a quantitative analysis of the physical processes responsible for halite cementation is still missing

This paper investigated the bubble migration and evolution during gas-liquid flow in oil-pipelines. Multi-scale bubbles migrated in the pipe while interacting with each other, causing coalescence and disintegration. The bubbles collided and coalesced, forming a new air pocket in the downward inclined pipe that blocked the transportation of both the gas and liquid phases. Consequently, the buoyance

One of the main problems of managed pressure drilling (MPD) is detection and monitoring of gas kicks from the formation to the annulus. The model is proposed to estimate the parameters of the gas kick and gas-liquid flow in a well during MPD process based on measurements performed only at the surface. A gas-liquid flow is described by the kinematic wave model. The ability of gaseous hydrocarbon to

Critical understanding of the reservoir pore-system is crucial for effective fluid-flow. Core-sedimentological description (40 core plugs), petrography (thin section and scanning electron microscopy with energy dispersive spectrometry), x-ray diffractometry, and high-resolution imaging were integrated to characterize pore-modification processes in a deeply buried (ca. 12470–12558 Ft.) non-marine sandstone

The large uncertainty in fracture characterization for shale gas reservoirs seriously affects the confidence in making forecasts, fracturing design, and taking recovery enhancement measures. It is of significance to make the most of multiple data in fracture characterization, including the measurements of hydraulic fracturing treatment, core, microseismic, production data, etc. Besides, handling the

Oil recovery during in situ combustion is majorly controlled by hydrocarbon oxidation and pyrolysis reactions, which govern fuel formation and heat evolution. Fuel deposition, in turn, can be accurately predicted in part through crude oil pyrolysis using thermogravimetry analysis (TGA). The theoretical models based on TGA runs, however, may be limited to crude oil samples at hand. In this study, we

When available core samples are limited, logging data becomes important in the lithology classification. For different lithologies, the distribution of logging data usually overlap each other, which increases the solution multiplicity of a single spatial point. The modeling of lithologic sequences depending on the vertical spatial relationship can reduce this multiplicity. To improve the modeling ability

The seepage coupling effect between the borehole rock mass and borehole fluid and the effective stress field distribution around the wellbore are obviously different under different working conditions of drilling, fracturing and completion, which affect the stability of horizontal borehole of shale gas reservoir. The physical, chemical, and mechanical properties of the shale in Longmaxi formations

Hydraulic-fracturing is an important well-stimulation technique, the fracture closure is inevitable during production. The existing pressure transient analysis models either ignore the length of fracture-closure segment that causes the explained fracture half-length to be smaller, or only use the fracture conductivity to evaluate fracture closure. To fully evaluate fracture closure and provide a reference

This article presents an integrated method for estimating parameters for an electric submersible pump system with process variables data. Validation of a phenomenological model is also performed. The parameters and the associated probability density function are obtained through Bayesian inference, and the model validation is achieved in two stages. The first one is the validation of the dynamic response

With the increasing demand of precisive reservoir characterization in exploration and development of oil and gas, wettability plays a more and more significant role because it influences oil and water distribution. The determination of wettability has been a challenge to the researchers focusing on this area. In this study, a new method is proposed for the determination of wettability based on resistivity

Polycrystalline diamond compact (PDC) cutters play a key role in the performance of PDC bits in the oil & gas drilling. The study of single cutter on the rock-breaking mechanism is very important for PDC bits to deal with challenging formations, especially when the wells become increasingly longer and complex. Both cutting efficiency and durability are always the focuses of attention for the researches

Heavy oil extraction currently presents economic and environmental challenges due to low prices and costly energy usage for their exploitation and transport. The use of heavy oil as a sustainable source of energy requires novel and well-engineered technologies. In-Situ (in-reservoir) Upgrading Technology, ISUT, is an EOR-Upgrading process that combines the use of a hot dense fluid (i.e., vacuum distillation

Fly ash is most commonly used as a partial replacement of Portland cement in lightweight oil-well cement systems. The fly ash is a waste material generated during coal combustion to generate energy. The material is facing an imminent phase-out due to global warming issues associated with coal combustion. This study, for the first time, investigates the potential of calcined calcium bentonite as an

Chelating agents were introduced because of the several issues associated with inorganic acids during oilfield stimulation. Carbonate and sandstone rocks have been stimulated using different kinds of acid systems and there is an engaging debate on chelating agents as an effective acid system. Several shortcomings of inorganic acid systems need to be addressed by chelating agents in order to be its

A series of mode I fracture toughness tests employing the semi-circular bend (SCB) and the pseudo-compact tension (pCT) methodologies have been performed with two sandstone types and specimens of 50 and 100 mm in diameter. The tests were complemented with the concurrent monitoring of acoustic emission (AE) activity using a multi-sensor array. With the obtained data, we compare and analyse the two testing

The Permian in western margin of Songliao Basin is a strategic potential field of oil and gas resources in northeastern China, but the systematic researches since few boreholes were drilled up to Permian strata, as well as there is a lack of seismic and well-logging data. This paper presents the lithological composition of the Permian Formations on the basis of regional geological survey in western

Solid reservoir bitumen is a geologic risk that controls reservoir quality and fluid distribution and has a profound impact on field development and near-field exploration. Understanding the exact mechanism responsible for the development of solid bitumen is therefore a prerequisite toward its proper quantification and mapping. A sandstone reservoir of an anticlinal gas condensate field was investigated

With the decreasing average size of new discoveries in mature production areas, the uncertainties in the base of oil field investment decisions are continually increasing. Fewer appraisal wells, which allow to decrease the amount of subsurface uncertainty, are typically drilled before the development of a small field compared to large fields. In this context, novel solutions must be established to

Overpressure can be widely observed in the Jurassic, Cretaceous and Paleogene reservoirs in the southern margin of the Junggar Basin, northwest China. The study region was subjected to intense tectonic stress from the neighbouring North Tianshan Mountains since the Miocene. However, the causes of tectonic stress-induced overpressure are still poorly understood. In this study, we considered the plots