Due to the severe heterogeneity of carbonate reservoirs, the traditional reservoir engineering methods for waterflooding performance forecast, mainly including the material balance equation, waterflooding characteristic curve and production decline curve, suffer from less reliability. The fine-scale reservoir numerical simulation is extremely time-consuming, because petrophysical properties in carbonate

Clays are among the main mineral components of shales and play a significant role in mechanical properties and anisotropy. However, it is difficult to quantify the impact of clay minerals on the mechanical properties of rocks because of the complex influence factors. In this study, we construct two artificial clay-rich shale samples containing kaolinite and smectite, respectively, and prepare one natural

Shear wave velocity (S-wave velocity or Vs) is one of the most critical issues for carbonate reservoirs characterization, because of its complexity of rock compositions and pore structures. The Xu-Payne petrophysical model is a commonly used method to predict S-wave velocity. However, the model excessively depends on the interpretation accuracy of rock compositions, pore structures, fluid properties

This study uses a commercial reservoir simulator to generate production rate data for shale wells with systematic variations in fracture treatment design parameters and a plausible range of reservoir properties. The synthetic well data is then used to generate diagnostic log-rate log-time plots, which allows for a distinction of four types of flow regimes. Such a distinction of flow regimes is of practical

The organic rich Lower Silurian Qusaiba Shale is the main effective source rock for most of the Paleozoic hydrocarbon in Eastern and central Arabia. Outcrop samples were obtained from Tayma quadrangle, northwest Saudi Arabia and extensive analyses were performed including petrophysical, geochemical, mineralogical, elemental, paleontological and lithofacies identification. Visual observation of samples

Asphaltene deposition prevention, mitigation, and management remains a major challenge to the oil industry due to its complexity, poor understanding, and inadequate predictive tools. A literature review study on asphaltene deposition revealed a lack of integrative models that link reservoir, wellbore, and surface facility to predict asphaltene deposition taking into account the effect of their interaction

In steam assisted gravity drainage (SAGD) operations, skim oil recycled to a free water knockout (FWKO) often results in poor water quality and rag formation at the oil/water interface. To improve water quality and demulsification efficiency in the presence of skim oil recycle, it is necessary to understand the status of oil and solids in the produced water throughout the process. In this paper, the

As for a typical machine-learning method, large volume of labeled examples is required to train and update neural parameters that are later used on new datasets. Well logs usually provide true values of elastic rock properties and enough amount of their correct answers may not often be available, due to budget limit and consumed time. In order to solve this problem, an unsupervised machine-learning

With the role of natural gas gaining increasing importance in the transition of the world energy system and addressing global climate change, accurate prediction of the price of natural gas becomes crucially important. This paper first introduces three widely used individual data-driven models, i.e., support vector regression (SVR) and long-term and short-term memory network (LSTM), and a modified

Organic-rich shale reservoirs are rich in reductive minerals, such as pyrite and other organic matters. The working fluid for the development of shale gas reservoirs contains large amount of dissolved oxygen. Once the working fluid enters the organic shale reservoir, it will oxidize the reducing components, cause mineral transformation, release solid phase particles, change the pore structures, and

Injection of low-salinity or smart water into the reservoir is one of the most common EOR techniques. This technique leads to more oil recovery in comparison to reservoir water and seawater injection. Several mechanisms explain the reasons for this increased recovery level, the most important of which is the wettability alteration towards water-wet conditions. However, in recent years, further mechanisms

The fracture debonding failure of cement plug/casing interface caused by the migration of underground fluid with pressure accumulation imposed serious challenges to wellbore integrity of abandoned wells. This paper presents an investigation with a view of quantifying the relationships between the fracture debonding height and the migration time of underground fluid. A new 3D numerical model of cement

Pore structure analysis is the basis of reservoir classification and exploitation, especially for tight reservoirs with complex pore throat systems. The sandy conglomerates in the Lower Cretaceous strata in northeastern China have attracted little attention from explorers in the past 50 years, but prospecting of promising tight gas reservoirs has recently begun in this area. Here, we report on the

Downhole electromagnetic transmitter is an important part of EM-MWD system, which can send low-frequency EM waves data from a downhole tool to surface in real time for oil and gas exploration. In order to reduce the volume and weight of the downhole electromagnetic transmitter and improve the depth and accuracy of petroleum exploration, a novel downhole electromagnetic transmitter topology for electromagnetic

This study investigates the effects of US monetary policy uncertainties on long-run oil and gas return volatility in the futures and spot markets using a GARCH-MIDAS (generalized autoregressive conditional heteroskedasticity mixed data sampling) model. The analysis comprises three periods: the pre-and post-crisis subsamples (based on the 2007–2009 financial crisis) and the whole sample (2003m1-2018m11)

The focus of the present work is to model the two-phase flow of oil and water in 2-D anisotropic petroleum reservoirs using a novel appropriate combination of a non-orthodox cell-centered Multipoint Flux Approximation with a Diamond Stencil (MPFA-D) finite volume method to discretize the pressure equation coupled to the very high-resolution Correction Procedure via Reconstruction (CPR) scheme for the

In recent years, geologists and petroleum engineers have struggled to clearly identify the mechanisms that drive productivity in horizontal, hydraulically-fractured oil wells producing from the middle member of the Bakken Formation. This paper fills a gap in the literature by showing how this play's heterogeneity affects factors that drive well productivity. It is important because understanding the

It is vital to design an optimum drilling fluid density for retaining the stability of wellbore wall in drilling engineering. Under estimated drilling fluid density will induce shear failure of wellbore wall. Conversely, wellbore wall will occur tensile failure. Drilling engineers have been looking for an optimum drilling fluid density for a long time. A new method to compute the optimum drilling fluid

The microscopic behavior shown by the aggregation/dispersion of modified nanoparticles was investigated. In the present study, the definition of aggregation range and standard were indicated. Subsequently, the type of graft chains and molecular chain length were taken into consideration as the critical factors in diffusion process. The parameters of diffusion coefficient and radial distribution function

The Muglad Basin is located in the hinterland of the Africa Continent. The weakness zones on the rigid basement of Sudanese Rift System and the relative movement occurring under the united action of regional stress field played controlling roles in the structural framework and its evolution in the overlying sedimentary covers. It is interesting that the present geological locations of the Central Africa

Petrophysical properties of tight sandstone reservoirs are complex which brings difficulties to fluid discrimination. Rock physics makes it possible to obtain petrophysical properties from elastic parameters. However, both deterministic rock physics and statistical rock physics have corresponding limitations. By combining deterministic rock physics and statistical rock physics, a joint posterior probability

Reactive flow happens during carbonate rock acidification. In the present study, carbonate rock dissolution process is investigated by lattice Boltzmann method at pore scale. The two immiscible fluids flow, solute transport and heat transfer are solved by the Shan-Chen multiphase multicomponent lattice Boltzmann model, mass transport lattice Boltzmann model and multicomponent thermal lattice Boltzmann

Nowadays the biological methods based on utilization of bacteria for different purposes in oilfields are becoming more and more popular because these methods potentially may become a cheaper alternative to chemical treatments. Gas hydrates formation in pipelines is the one of the main flow assurance problems. In previous works it has been shown that some biodegraded oils can have components that may

The permeability decrease caused by the increase in effective stress notably influences the development of tight sandstone reservoirs. Therefore, it is necessary to study permeability stress sensitivity characteristics. Permeability stress sensitivity evaluation experiments of tight sandstone were conducted. On this basis, the influencing factors were analyzed by means of scanning electron microscopy

Fracture toughness property is often ignored but has a significant impact on the hydraulic fracture design, i.e. length and height. It represents the resistance of the rock to hydraulic fracturing and is a direct indicator of rock fracability. It is difficult to measure fracture toughness in shales using current experimental procedures designed for conventional rocks largely due to mechanical and chemical

The leaked contaminants from buried oil pipelines have a great potential to damage the ecological environment. It is significant to accurately and effectively predict the migration destination and diffusion range of oil contaminants in soil, which can keep contaminants to a minimum, and also can help to formulate the environmental impact assessment and remediation plan. In this paper, the Quartet Structure

In order to overcome disadvantages of thermal recovery technologies such as high cost and air pollution, chemical flooding for ordinary heavy oil by viscosity reducer flooding was studied. The EOR mechanisms of viscosity reducer flooding to improve heavy oil recovery were studied by physical experiments and numerical simulation methods. First, the performance of the viscosity reducer was evaluated

Abnormally high-porosity zones in deep reservoirs are widely developed in the fourth member of the Eocene Shahejie Formation (Es4) in the fault-step zone of the Bonan Sag, Jiyang Depression, Bohai Bay Basin, China. However, research on reservoir diversity in these abnormally high-porosity zones has focused on the shallow parts of the reservoirs, and their genetic mechanisms remain unclear, restricting

Hydraulic fractures initialized from different perforations have different contributions to well production. Therefore, it is essential to study the competitive propagation of hydraulic fractures among multiple perforations. In this study, a fracture-pore flow model coupled with wellbore flow was developed and implemented in a three-dimensional numerical model to simulate multi-perforating hydraulic

The Lower Paleozoic Ordovician Wufeng Formation and the Silurian Longmaxi Formation shale in the southeastern part of Sichuan Basin in China are the key strata for shale gas exploration. In this paper, based on a large number of outcrops, cores and natural gamma spectroscopy logs combined with scanning electron microscopy, geochemical parameter testing and mineral component analysis, the geological

Mineral oils are frequently used for the making of synthetic-based drilling fluids. However, there are several downsides associated with these oils. These mineral oils are non-renewable, toxic in nature, non-biodegradable and prompting towards the incredible expense of waste treatment. In this research article, an anionic surfactant sodium methyl ester sulfonate (SMES) was synthesized using sunflower

Resin-coated ceramic proppants have a thin layer of resin coating on a ceramic body. In this study, we performed experiments to investigate the transport and settling behavior of resin-coated ceramic proppant in three rough vertical fracture models that are replications of different rocks. We studied the effects of the influential factors on the transport behavior of the proppant, including the location

Recently, the model development of pressure transient analysis in wells with large-scale fracturing treatments has attracted more and more attention. However, a little work has involved the complex fracture networks with fracture hits. In this study, the transient pressure behaviors of a child well with complex fracture geometries and fracture hits are studied, using an efficient semi-analytical model

Drill pipe rotation is considered a relevant factor for cuttings transport and hole cleaning. However, in the term “rotation” is often used as a moniker for the combination of plain drill pipe rotation around its own axis and more complex lateral motion, as many laboratory setups feature an unconstrained drill string. Lateral motion is generally considered to benefit the transports of cuttings due

An accurate evaluation of injectivity is essential to the economics of any chemical EOR process. Most commercial simulators enable non-Newtonian behaviour modelling but it is often overlooked due to inadequate grid resolution. Indeed, in cases where shear-thinning fluids are injected in a reservoir, shear rates and viscosities in the vicinity of the wellbore can be poorly estimated if the spatial resolution

Intermittent proppant injection into hydraulic fractures is a newly-developing technology in well stimulation. It is designed to form voids inside proppant packs which serve as highly conductive channels for oil and gas transport. However, it remains unclear the extent to which this non-homogeneous, pulse-like proppant concentration persists over the extent of the fracture. This paper models proppant

Surface microbial geochemistry (SMG) is an effective tool to predict the occurrence of oil/gas deposits at the exploration phase. However, for oil/gas fields in the production period, the significance of SMG is always weakened since the existing microbial indicators for reservoir characterization by SMG are limited. In this study, we systematically analyzed the abundances of live and dead methane-oxidizing

Hydrocarbons have been the primary resource of the energy of civilizations for hundreds of years historically and still play a vital role in accomplishing the daily life occupations in every sector. With the upcoming dramatic rate increase of the human population reaching 9.8 billion by 2030, the latter requires an uprising supply of goods and services that can be achieved through the increased rate

The process of minimizing the difference between observed and simulated data by adjusting the input model parameters is typically called history matching. Geological parameterization approaches allow high-dimensional geological models to be replaced by relatively low-dimensional parameters in history matching problem. It is important because of the incompetence of optimization algorithms in problems

The organic geochemical traits of Carboniferous to Permian hydrocarbon source rocks (SRs) from the Mahu Sag, Junggar basin, have been investigated in terms of thermal maturity (TM), hydrocarbon potential (HP), organic matter (OM) source input and paleoenvironment. A total of forty-seven (47) core samples from five (5) wells have been surveyed through standard organic geochemical approaches, including

Environmental protection is an increasing concern for plugged and abandoned wells within the Gulf of Mexico. Leakage, however, has been shown to occur before the plug and abandonment (P&A) process takes place. The cement used when completing a well may develop leakage paths in the form of microannuli gaps between the casing and cement due to decreases in pressure and/or temperature. The goal of this

The beam pumping unit has the characteristics of simple structure, reliability and durability. It is the most widely used artificial lifting method in oil fields worldwide. However, the inherent defects of the 4-bar linkage structure of the beam pumping unit result in high impact, low system efficiency and large motor rated power. In order to improve the efficiency of the pumping unit system and make

A different approach based on existing spatiotemporal models is developed in this research for forecasting the production flow rates of a group of adjacent wells in a reservoir. Unlike the previous single-well analysis techniques, this new methodology tries to forecast the flow rates of a number of producing wells located in a certain neighborhood. It also takes into account the variety of flow rate

Electric Submersible Pump (ESP) is currently widely employed to help enhance production for nonlinear-flowing well with high production and high water cut well. However, ESP broken shaft is common in the oil industry. The broken shaft leads to production disruptions, resulting in significant economic losses. The objective of this paper is to evaluate Principal Component Analysis (PCA) as an unsupervised

Hydrocarbon-bearing reservoirs are usually divided into multiple compartments with distinct properties by linear leaky faults. This kind of heterogeneous reservoir is usually called linear composite reservoir. Hydraulic fracturing is an important technology to significantly improve oil/gas production, and has been widely applied to the development of various oil/gas reservoirs. However, the literature

Recently the focus of the oil and gas industry is to find the alternative material for well barrier applications. Geopolymers are among the suggested materials, which could be used in the future to solve the well integrity issues rooted by the properties of Portland cement. Previous study with rock-based geopolymer indicates the potential of geopolymer to be used as a barrier material. However, there

Clays play important roles in velocity anisotropy. Unlike brittle minerals, e.g., quartz, ductile clays are commonly more easily affected by mechanical compaction. Hence, clays tend to have a platy structure that might introduce significant velocity anisotropy. Cracks developed in clay-rich shales also have substantial influences on the shale elastic anisotropy and hydraulic stimulation. However, crack

This work introduces 3D lattice modeling of hydraulic fracturing initiation and near-wellbore propagation for different perforation models, including spiral perforation, oriented perforation and Tristim perforation. For each perforation model, a total of six perforation tunnels are explicitly modeled and the representative intermediate states are chosen to analyze the results. The numerical simulation