Well Productivity Index
Compute an oil well's productivity index (PI), PI = Q/(Pr − Pwf), the ratio of the produced rate to the pressure differential (drawdown) between the reservoir (Pr) and the bottomhole (Pwf). It measures how easily the well produces: a high PI indicates good permeability and reservoir connection. It is the basis of lift design and production forecasting. Enter the rate and the reservoir and bottomhole pressures.
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Índice de produtividade do poço
O índice de produtividade (IP) mede a 'generosidade' de um poço: quantos barris por dia ele produz para cada psi de queda de pressão. IP = Q/(Pr − Pwf), onde a diferença Pr − Pwf é o drawdown — o quanto se 'puxa' a pressão no fundo do poço (Pwf) abaixo da pressão do reservatório (Pr) para fazer o óleo fluir. Um IP alto revela boa permeabilidade, espessura produtiva generosa e boa conexão poço-reservatório (sem dano de formação); um IP baixo sinaliza rocha apertada ou um poço 'machucado' que talvez precise de estimulação (acidificação, fraturamento). O IP é a base da curva de IPR (Inflow Performance Relationship), que prevê quanto o poço produzirá em diferentes pressões de fundo — informação essencial para projetar o sistema de elevação (bombas, gas lift) e otimizar a produção. Informe a vazão e as pressões de reservatório e de fundo.
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Shale Volume from Gamma Ray (Larionov)
Estimates the shale volume of a formation from the gamma ray log, the first step in any petrophysical well evaluation. The calculation normalizes the zone reading between the cleanest sand and the most radioactive shale in the interval, giving the gamma ray index IGR = (GR − GR min) ÷ (GR max − GR min), and then applies the non-linear Larionov curve, Vsh = 0.083 × (2^(3.7 × IGR) − 1). The result is the fraction of rock volume occupied by clay, as a percentage: intervals above 30 to 40% are usually discarded as reservoir, and the value later feeds the porosity and water saturation corrections for shaly sands. The Larionov curve for Tertiary, poorly consolidated rocks was adopted, which is the usual one in young sedimentary basins; for Mesozoic or older rocks the literature uses Vsh = 0.33 × (2^(2 × IGR) − 1), which returns far larger volumes for the same IGR. Enter the zone gamma ray reading, the minimum reading and the maximum reading of the interval.
Clay Activity (Skempton)
Computes clay activity as defined by Skempton, A = PI ÷ (% of particles finer than 2 μm), the ratio of the soil's plasticity index to the truly clay-sized fraction. It separates the clay mineral's effect from the mere amount of fines: two soils with the same PI behave very differently if one owes its plasticity to a little highly active clay and the other to a lot of inert clay. The usual classification is A < 0.75 inactive (kaolinite), 0.75 to 1.25 normal (illite) and A > 1.25 active (montmorillonite), the range where the expansive soils that warp pavements and shallow foundations are found. Enter the plasticity index and the clay fraction.
Mixture Exposure Index
Calculate the combined exposure index to a mixture of chemical agents by the additivity rule, I = (C₁ ÷ TLV₁) + (C₂ ÷ TLV₂), summing the ratio of measured concentration to tolerance limit (TLV) for each substance. The dimensionless result assesses the joint effect of contaminants acting on the same target organ: if the sum exceeds 1, the combined exposure surpasses the limit, even if no single substance is above its own. It is the ACGIH and NR-15 criterion for mixtures with additive effects. Enter the concentrations and tolerance limits of two substances.
Pore Pressure Gradient
Compute a formation's pore pressure gradient by dividing the pore pressure by the vertical depth, in psi/ft (or kPa/m). The normal saltwater gradient is ~0.465 psi/ft; higher values indicate overpressure (dangerous, can cause kicks and blowouts) and lower ones, underpressure. It is a critical drilling-safety parameter, since it sets the mud weight needed to balance the formation. Enter the pore pressure and the vertical depth.
Material Removal Rate (Turning)
Calculate the material removal rate (MRR) in turning, Q = Vc·a_p·f, from the cutting speed Vc (m/min), the depth of cut a_p (mm) and the feed f (mm/rev). The result, in cm³/min, is the material volume removed per unit time — the direct measure of machining PRODUCTIVITY. Maximizing MRR (cutting fabrication time and cost per part) is the core goal in roughing, achieved by increasing any of the three factors: cutting speed, depth or feed. But there are limits and trade-offs: higher speed shortens tool life (Taylor); higher depth and feed raise the cutting force and power required (which may exceed machine capacity or cause chatter) and worsen finish. So the typical strategy uses high MRR in ROUGHING (productivity) and low in FINISHING (precision and roughness). MRR times the material's specific cutting energy gives the required power. Enter the cutting speed, depth of cut and feed.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.