An automated tool that facilitates the utilization of oil lift curves (well head flowing pressure versus rate) is essential in order to obtain consistent and accurate lift results efficiently in E&P companies.
This paper describes the method used for implementing such a tool and how it integrates with other related information systems and software packages. It explains how these techniques can be applied in some reservoir and production areas to achieve the best well performance and make future predictions.
The theory employed in generating lift curves is based on locating the intersection between a well's Inflow Performance Relationship (IPR) and a Vertical Flow Performance (VFP) curve. It returns the flow rate and Bottom Hole Pressure (BHP).
IPR depends on reservoir pressure and a well's productivity index.
The VFP curve is generated from ECLIPSE or PROSPER analysis software package at specified values of the well's tubing head pressure, water fraction, gas fraction and artificial lift quantity.
The business cycle starts when the daily oil allowables for all Well/Strings are defined at the beginning of each month by the Reservoir Section and sent to the Production Section. Consequently, the corresponding daily required well head flowing pressures (WHFPs) are manually derived at the office from the latest available Lift Curves initially generated by the Reservoir section. After the implementation of the derived WHFPs at the Field's site, the measured WHFP for each well/string is introduced to the oil allocation business process. The corresponding daily well/string estimated oil rates are also manually obtained from the same Lift Curves. At the end of the month, measured WHFPs and estimated oil rates are sent to the Reservoir Section. Data is revised and finalized by referring to the latest available lift curves in order to use, it in calculating the daily allocated oil rates. Lift Curves are updated by both parties from Production Flow Test Results to fit within the latest test points. On the other side they are used by Well Testing Section as a measure for accepting or rejecting Production Flow Tests. This depends on the location of the oil rate Vs WHFP point measured by the test, if it lies within the general trend of the latest Lift Curve or not.