A Model for Extending the Heptanes plus Fraction for Trinidad Gas Condensates

A Critical Review on Mathematical Functions Employed for Heptane Plus Characterization in Gas Condensate Reservoirs: Lessons Learned and Future Development

“…Consider the distribution graphed by Hosein and McCain (2009) obtained a gas condensate well PL6 in Trinidad, using the following data In this graph, it is seen that the graph itself can be divided into four sections of the trend line, as what Mayrhoo and Hosein (2014) did in his work of four coefficients model. Mayrhoo and Hosein (2014) however, use the normal graph of percent mole to molecular weight, assuming linearity of all the points plotted. This leads to inaccuracy due to the rounding of the function.…”

“…Ahmed's method was tested by Mayrhoo and Hosein (2014) for twelve samples of gas condensate PVT obtained in Trinidad, and the results yielded better performance compared the previous models, ranging from 8-18%, but the most important flaw in this method is the overprediction of SCN7 group by 23%, which implies that this method cannot be utilized for Trinidad condensates.…”

“…In this publication, the author reviews the advantages and disadvantages of exponential distribution, threeparameter gamma distribution function, and the four-parameter coefficient model from Mayrhoo and Hosein (2014) and the author will propose a new model based on natural logarithmic function to properly accommodate discontinuous function.…”

“…Mayrhoo and Hosein (2014) attempted to reformulate the flaws in Ahmed et al (1985) scheme by adding two more coefficients and dividing the PVT into four segments, to properly isolate the discontinuities, which results in a modified coefficient based on the pictures below. Mayrhoo and Hosein (2014) divided the segments as  Segment 1 is from SCN7 to SCN 8 due to the discontinuities whilst segment 2 is from SCN 8 to 12  Segment 3 is from SCN 12 to SCN 13and segment 4 is beyond SCN 13…”

“…In gas condensate reservoirs, proper fluid characterization should bring multiplier effects in the difficulty of production, field development, and surface treatment process design. However, it is a known field practice that extended composition of a gas condensate sample is not available experimentally due to technological constraints and economic consideration, therefore mathematical models popularly known as "splitting schemes" are often employed (Mayrhoo and Hosein, 2014).…”