The Continuous Carbon/Oxygen Log Basic Concepts and Recent Field Experiences

Abstract

Summary We describe an integrated computer system, the Selective Production Scheduling (SPS) system, that is used by the management of Kuwait Oil CO. (KOC) for scheduling oil and gas production in daily operations. The system is able to draw together management objectives by determining operational variables to produce an optimal schedule of production. The mathematical techniques of linear programming are used in selecting the optimal schedule. Introduction KOC is the major oil producer in Kuwait. Its operating facilities include crude oil gathering centers, gas compression stations, oil and gas pipeline networks, liquefied petroleum gas (LPO) plants, and crude oil and LPG storage and export facilities. There is extra plant capacity at most locations to handle peak throughput and to provide operating flexibility. Any operating policy should satisfy daily quantitative and qualitative production requirements while observing any short-term management plans such as plant and well maintenance and testing schedules or reservoir pressure maintenance schemes. The operating policy also should be consistent with any long-term strategies for balanced and efficient reservoir depletion. Changing short-term objectives and fluctuating oil, gas, and LPG demands create a selectivity problem, and there are many potentially feasible operating policies. The number of variables involved and the complex interaction of operating objectives make the task of selecting the optimal production policy virtually impossible without the aid of a computerized mathematical model. In this discussion of SPS, special emphasis is given toproduction facilities considered,data acquisition procedures and database facilities,basic mathematical formulation,system output and the daily cycle of use,limitations of the system, andother applications of SPS. Production Network The production network (Fig. 1) considered by SPS includes several hundred oil wells, each producing from either one or two separate zones. Oil flows to 26 gathering centers with widely ranging capacities and a variety of separator configurations. Inside the gathering centers, the associated gas is separated from the oil in two to four stages, depending on the pressure in the producing reservoirs. Wet crude is dehydrated and desalted as necessary. The stabilized crude oil then is pumped or gravitated into the-crude transit system and finally to the storage and export terminals. The separated gas is collected, dried, and desulfurized (if necessary) before being compressed for transmission to one of the LPG plants. The gas collection system comprises a high- and a low-pressure network, served by 47 compressors with an average size of 8,200 hp each. At the LPG plants the gas is fractionated into propane, butane, natural gasoline, and unliquefied gases. The liquid products are stored for future export and the unliquefied gases are distributed by means of two fuel gas networks (high- and low-pressure) to consumers in Kuwait. Some of the unliquefied gas is sent for reinjection into selected reservoirs for pressure maintenance. The SPS system is advised on a daily basis of changes in plant and equipment availability, and it updates its data base accordingly. This is essential since any production schedule produced by SPS must not violate any physical constraint imposed by the unavailability of field equipment. JPT P. 487^