# Inflow performance relationship calculator common

Two-phase Inflow Performance Relationship Prediction Using Two Artificial in the reservoir, commonly called the inflow performance relationship. .. Concerning the calculation of inflow performance of wells producing. properties, the well productivity and Inflow Performance Relationship (IPR) for both use of horizontal wells became more common, studies on horizontal well deliverability calculation and so is one of the models chosen for comparison. Inflow performance relationship (IPR) is one of the vital tools required to Consequently, it is common to observe drastic permeability variations within a single theoretical calculation showing a curved relationship between the flow rate and.

The nk values range from 0. InAvery and Evans [ 22 D. IPR curves were also used during enhanced oil recovery process where Yeu et al. After emerging of the multi-lateral technology, Guo et al. These are few of the many applications of IPR in oil industry. Most of the IPR correlations suffer from common limitations that they are not explicitly function of the different reservoir rock and fluid properties that vary from one reservoir to another or its difficulty to be applied.

This will affect the accuracy of the correlations especially if the reservoir properties of the well under study are completely different from the properties used in generating these correlations.

In this work, a single well 3D radial reservoir model with solution gas-drive as the main driving mechanism was built and reservoir simulation was used to generate different IPRs by changing the reservoir rock and fluid properties. The most sensitive reservoir rock and fluid properties were selected to generate the new IPR correlation.

This new correlation is based on generating combination of the selected reservoir rock and fluid properties and run the simulation models to generate different IPR curves. Then, the non-parametric regression technique was used to generate the new IPR correlation that is explicitly function of the reservoir rock and fluid properties that highly affect the IPR curve.

**Productivity Index IPR**

The outline of the paper is as follows. Firstly, we presented the assumptions we used in generating the single well reservoir simulation model. Secondly, we studied the sensitivity of the IPR towards different rock and fluid parameters to choose the highly sensitive parameters to be used in the IPR correlation.

Thirdly, we presented the nonlinear and non-parametric regression techniques we used to develop the IPR correlation that is explicitly function of reservoir rock and fluid properties. Finally, we presented the validation of the new correlation based on different synthetic and field cases.

The reservoir simulator was used to construct reservoir models that cover a wide range of rock and fluid properties. The slope, b, is 0. These deliverability coefficients can be use to develop a deliverability equation after the form of Eq. A similar analysis can be undertaken for the pseudopressure data shown in Fig. These coefficients are used to write the deliverability equation as Isochronal test Cullendar [5] proposed the isochronal test to overcome the need to obtain a series of stabilized flow rates required for the flow-after-flow test for the slow-to-stabilize well.

This test consists of producing the well at several different flow rates with flowing periods of equal duration. Each flow period is separated by a shut-in period in which the shut-in bottomhole pressure is allowed to stabilize at essentially the average reservoir pressure. The test also requires that an extended stabilized flow point be obtained.

### Gas well deliverability -

The test method is based on the principle that the radius of investigation is a function of the flow period and not the flow rate. Thus, for equal flow periods, the same drainage radius is investigated in spite of the actual flow rates.

To analyze the data from an isochronal test, the flow data from the equal flow periods is plotted according to the Rawlins and Schellhardt1 or Houpeurt [2] methods. These data points are used to determine the slope of the deliverability curve. The stabilized flow point is then used to estimate the flow coefficient, C, for the Rawlins and Schellhardt method or the intercept, a, for the Houpert method by extending the slope of the multirate data to the stabilized flow point.

Example 2 Table 4 details isochronal test data for a particular well in which the flow periods are one hour in duration. The Rawlins and Schellhardt approach with pressures and the Houpeurt approach with pseudopressures are used to demonstrate the analysis of isochronal test data. Table 5 presents the plotting data for both methods. Solution A straight line can be constructed through the three transient points to yield a slope of 1. The inverse of the slope defines the deliverability exponent, n, which is 0.

The slope through the transient points is extended to the stabilized flow point to depict the deliverability curve. The flow coefficient, C, is calculated from the stabilized flow point, The flow exponent and flow coefficient are used to define the Rawlins and Schellhardt deliverability equation for this well, For an atmospheric pressure of A similar analysis can be undertaken with pseudopressures following the same method described for the pressures squared.

Applying the Houpeurt approach, the transient flow points are used to determine the slope of the best-fit straight line constructed through the data points. This slope is used to determine the intercept from the stabilized flow point. From the plot, the slope is determined to be 0. As the analysis of the flow-after-flow test data showed, the Rawlins and Schellhardt and Houpeurt methods yield different estimates of deliverability.

## Gas well deliverability

Modified isochronal test For some low-permeability wells, the time required to obtain stabilized shut-in pressures may be impractical. To overcome this limitation, Katz et al. The modified isochronal test is essentially the same as the isochronal test, except the shut-in periods separating the flow periods are equal to or longer than the flow periods.

The method also requires the extended stabilized flow point and a stabilized shut-in bottomhole pressure. The modified isochronal test method is less accurate than the isochronal method because the shut-in pressure is not allowed to return to the average reservoir pressure.

In the analysis of the collected data, the measured bottomhole pressure obtained just before the beginning of the flow period is used in Eqs. The analysis of the data is exactly the same as that used to analyze the isochronal test data. With the Rawlins and Schellhardt data, the transient flow points are used to construct a best-fit straight line through the data points. The inverse of the slope of this line yields the deliverability exponent, n. The deliverability exponent is then used with the data of the stabilized flow point to estimate the flow coefficientC, with Eqs.

In the Houpeurt analysis, a best-fit straight line is constructed through the transient flow points to yield the slope, b. Once the slope is determined, it is used with the stabilized flow point in the appropriate equation for pressure or pseudopressure Eqs. Once the flow coefficients are determined by either analysis method, the deliverability equation can be written and used to estimate the AOF and production rates for the well. Transient test methods The multiple modified isochronal test consists of all transient test data and eliminates the need for stabilized flow or pressure data.

The analysis method requires estimates of drainage area and shape along with additional reservoir and fluid property data that are not required with the previous deliverability test methods. As a result, the analysis techniques are more complex than for flow-after-flow, isochronal, or modified isochronal test data. However, the method provides a means to estimate deliverability of slow-in-stabilizing wells and consists of running a minimum of three modified isochronal tests with each test composed of a minimum of three flow rates.

To analyze the test data, modifications to the Rawlins and Schellhardt analysis have been proposed by Hinchman, Kazemi, and Poettmann [7] while modifications to the Houpeurt pressure-squared technique have proposed by Brar and Aziz, [8] Poettmann, [9] and Brar and Mattar. Future performance methods The petroleum engineer is required to forecast or predict gas well performance as the reservoir pressure depletes. There are several methods to assist in making these future performance estimates, including the direct application of the appropriate analytical solution to provide estimates of rate vs.

However, the use of Eqs.