Unconventional Method of Estimating Oilfield Reserve Initially in Place Using Decline Trends Analyses Techniques

Methods to estimate reserves, recovery factor and time are highlighted using uconventional method, to reduce the challenges in an oilfield development. General Information about reserves production estimation using long and short production data is collated. The collated data are plotted against time to build production decline curves. The curves are used to estimate the decline rate trends and constants. The decline constant is then used to predict reserves cumulative recovery. The rate trend is extrapolated to abandonment for estimation of reserves initially in place, recovery factor and the correspondent time. The reserves values are compared with field values for accuracy. It was observed that the result using data from long time production history accuracy was 99.98% while evaluation models built with data from short production history accuracy was 98.64%. The models are then adopted after validation. The validated curves are used to build the governing models which are finally used in estimating cumulative reserves recovery and initially in place. It is concluded that accurate reserves, recovery factor and time estimation challenges can be achieved/matched up using rate decline trend techniques.

The Impact of the Geometry of the Effective Propped Volume on the Economic Performance of Shale Gas Well Production

We analyze the effect that the geometry of the Effective Propped Volume (EPV) has on the economic performance of hydrofractured multistage shale gas wells. We study the sensitivity of gas production to the EPV’s geometry and we compare it with the sensitivity to other parameters whose relevance in the production of shale gas is well known: porosity, kerogen content and permeability induced in the Stimulated Recovery Volume (SRV). To understand these sensitivities, we develop a high-fidelity 3D numerical model of shale gas flow that allows determining both the Estimated Ultimate Recovery (EUR) of gas as well as analyzing the decline curves of gas production (DCA). We find that the geometry of the EPV plays an important role in the economic performance and gas production of shale wells. The relative contribution of EPV geometry is comparable to that of induced permeability of the SRV or formation porosity. Our results may lead to interesting technological developments in the oild and gas industry that improve economic efficiency in shale gas production.

Average Fracture Compressibility from Flowback Data

Summary We propose a novel method for estimating average fracture compressibility cf¯ during flowback process and apply it to flowback data from 10 multifractured horizontal wells completed in Woodford (WF) and Meramec (MM) formations. We conduct complementary diagnostic flow-regime analyses and calculate cf¯ by combining a flowing-material-balance (FMB) equation with pressure-normalized-rate (PNR)-decline analysis. Flowback data of these wells show up to 2 weeks of single-phase water production followed by hydrocarbon breakthrough. Plots of water-rate-normalized pressure and its derivative show pronounced unit slopes, suggesting boundary-dominated flow (BDF) of water in fractures during single-phase flow. Water PNR decline curves follow a harmonic trend during single-phase- and multiphase-flow periods. Ultimate water production from the forecasted harmonic trend gives an estimate of initial fracture volume. The cf¯ estimates for these wells are verified by comparing them with the ones from the Aguilera (1999) type curves for natural fractures and experimental data. The results show that our cf¯ estimates (4 to 22×10−5 psi−1) are close to the lower limit of the values estimated by previous studies, which can be explained by the presence of proppants in hydraulic fractures.

INFLUENCE OF BUCKLING FORMS INTERACTION ON STIFFENED PLATE BEARING CAPACITY

The work is devoted to studying the influence of initial geometric imperfections on a value of the peak load for the compressed stiffened plate with the two-fold buckling load. The finite-element set MSC PATRAN – NASTRAN was used for solving the set tasks. When modelling the stiffened plate, flat four-unit elements were used. Geometric non-linearity was assumed for calculations. The plate material was regarded as perfectly elastic. Buckling forces of stiffened plate at the two-fold buckling load were calculated (simultaneous buckling failure on the form of the plate total bending and on the local form of wave formation in stiffened ribs). Equilibrium state curves, peak load decline curves depending on initial imperfection values and the bifurcation surface were plotted.

Outbreak analysis with a logistic growth model shows COVID-19 suppression dynamics in China

China reported a major outbreak of a novel coronavirus, SARS-CoV2, from mid-January till mid-March 2020. The number of cases outside China is now growing fast, while in mainland China the virus outbreak is largely under control. We review the epidemic virus growth and decline curves in China using a phenomenological logistic growth model to summarize the outbreak dynamics using three parameters that characterize the epidemic’s timing, rate and peak. During the initial phase, the number of virus cases doubled every 2.7 (range 2.2 - 4.4) days. The rate of increase in the number of reported cases peaked approximately 10 days after suppression measures were started on 23-25 January 2020. The peak in the number of reported sick cases occurred on average 18 days after the start of measures. From the time of starting measures till the peak, the number of cases increased by a factor 39 in the province Hubei, and by a factor 9.5 for all of China (range: 6.2-20.4 in the other provinces). Complete suppression took up to 2 months (range: 23-57d.), during which period severe restrictions, social distancing measures, testing and isolation of cases were in place. The suppression of the disease in China has been successful, demonstrating that suppression is a viable strategy to contain SARS-CoV2.

Numerical investigation of MHD Prandtl melted fluid flow towards a cylindrical surface: comprehensive outcomes

In this work, we explore the mathematical structuring of Prandtl fluid flow towards an inclined stretched cylinder. Modelling of this newly proposed model is manifested in three different ways. A momentum equation for the concerned model is established under the role of an induced Lorentz field, whereas the thermal and mass transport mechanisms account for the role of the heat generation–absorption process and chemical reaction phenomenon. For a more realistic and schematic analyses of the present problem, the field expressions are expressed mathematically in terms of PDEs. The obtained intricate differential system is converted into ODEs by means of transformations. Improved numerical simulation is conducted using the Cash and Carp method to foresee the pattern of thermophysical distribution towards existing involved constraints. It is noticed that Prandtl fluid velocity declines for increases in both the Prandtl fluid parameter and elastic parameter. Further, the fluid temperature increases the effects of the magnetic field, curvature, and the melting parameters while the concentration profile shows decline curves for both the Schmidt and chemical reaction parameters. It is important to note that this nature is preserved for both the magnetized and non-magnetized cases.

A NEW METHOD OF DECLINE CURVE FORECASTING FOR PROJECT WELLS ON THE BASE OF MACHINE LEARNING ALGORITHMS

The article describes new decline curves (DC) forecasting method for project wells. The method is based on the integration of manual grouping of DC and machine learning (ML) algorithms appliance. ML allows finding hidden connections between features and the output. Article includes the decline curves analysis of two well completion types: horizontal and slanted wells, which illustrates that horizontal wells are more effective than slanted.