Optimization and Prediction of Sucker Rod Pump Performance on Well X-1 in Field X in the Future

The performance of the sucker rod pump is influenced by the characteristics of the well and reservoir such as pressure, well productivity, physical properties of the fluid, depth and diameter of the well. Therefore, pumping pumps need to be designed and optimized taking into account these conditions. As time goes on production changes in physical properties occur in the reservoir such as a decrease in reservoir pressure and a decrease in well productivity. Changes in the physical properties of the reservoir will affect the performance of the sucker rod pump. The purpose of this study is to design a sucker rod pump at X-1 well and forecast production in the future. The flow rate determination is obtained from the point of intersection between the pump intake pressure curve and IPR curves both in the present and in the future. In this study the pump speed is set at 10 SPM. Based on this method it was found that the well can produce with a flow rate of 1132 bpd with an oil flow rate of 27 bpd. The stroke length for this condition is 304 inch. Over time the production is estimated to cause the pressure to decrease to 1010 psi in 2040. The decrease in reservoir pressure causes the reduction in the flow rate of sucker rod pump to 1046 bpd with an oil flow rate of 14.6 bopd. So that the magnitude of the reduction in the flow rate of liquid between 2019 and 2040 was 7.6%, while the decrease in the oil flow rate was 45.9%. If the speed is set at 10 SPM, the stroke length needs to be reduced with time. The stroke length was designed to be 304 inches in 3019 and reduced to 281 inches in 2040.


I. INTRODUCTION
Field X is a field that has long been produced. Therefore Field X is included in a mature field. The field is located in South Kalimantan Province. As the production time goes on, changes in the physical properties of the reservoir occur. The initial pressure of Reservoir X at Field X at the beginning of production was 1628 psi. At this time reservoir X pressure drops below bubble point pressure to 1100 psi. Most of the wells in Field X produce fluid using artificial lift equipment. The artificial lifting equipment that is commonly used in Field X is sucker rod pump (SRP) and electric submersible pump (ESP).
In this study, an SRP design was conducted to be applied on well X-1. The well produces fluid from Reservoir X, one of the reservoirs in Field X. In order to produce fluid using the pump optimally, it is necessary to adjust the pump speed (N) and stroke length (S). Pump speed was set at 10 spm. So that in this study an allowable stroke length was selected that produces at the optimum flow rate.
As mentioned above that reservoir pressure declines as production time increases. A decrease in reservoir pressure results in a decrease in flow rate in the future. Accordingly it is necessary to adjust stroke length in the future. In addition, the decline in production rate and reservoir pressure will affect the requirement of horse power.
Based on the background that has been described, then several things can be analysed, such as the allowable stroke length for X-1 well that provide optimum production rates and future production rate and stroke length adjustment due to reservoir pressure decline. Then, the purpose of this study is to design a pump pump at X-1 well and to analyze production rate changes and stroke length adjustment in the future.

II. METODOLOGI
The research procedure carried out in this study is shown in Figure 1. Basically the research stages include data collection, pump optimization, and prediction of pump performance in the future. The procedure of the research is as follows:   Table 1. The change in reservoir pressure and water cut (WC) [8] in the future can be predicted by using the regression equation as shown in Figures 2 and 3, respectively. The estimated decline of the reservoir pressure was used to construct inflow performance relationship curves at years 2025, 2030, 2035, and 2040.

III. RESULTS AND DISCUSSION
At the condition of reservoir pressure P r , under bubble / boiling pressure, the Vogel IPR equation can be used to depict the relationship between flow rate and bottom hole pressure. Based on the data given in Table 1 where q max is 2187 bpd and reservoir pressure P r is 1100 psi, then the IPR curve shown in Figure 4. Future IPR curves can be made using Eickmeier [6] based on estimated future reservoir pressure shown in Figure 4.  at 10 spm. Since the present flow rate that was obtained from the intersection of the curves was 1132 bpd then the stroke length (S) was 304 inch. The future stroke lengths are given in Table 2. The table show that the stroke length decreases as flow rate declines. Therefore the stroke length of the pump should be adjusted in the future. The maximum polished rod load occurs in the upstroke motion of the rod where the plunger has to lift up the fluid. While the minimum polished rod load (Minimum Polished Rod Load) occurs when the equipment move down. Table 3 shows the results of the calculation of constants  1 ,  2 , PPRL, and MPRL. The stress experienced by the material lies between the maximum stress,  max , and minimum stress,  min . And the maximum stress must be lower than the allowable stress, allowable. Table 4 shows the value of maximum stress, max, minimum stress, min, and allowable stress,  allowable ,, for each combination of time, N, and S. The stress experienced by the material lies between the maximum stress,  max , and minimum stress,  min . And the maximum stress must be lower than the allowable stress, allowable. Table 4 shows the value of maximum stress, max, minimum stress, min, and allowable stress,  allowable ,, for each combination of time, N, and S.