Kermit E. Brown

Economic Approach to Oil Production and Gas Allocation in Continuous Gas Lift (includes associated papers 10858 and 10865 )

Allocation of gas to wells on continuous lift can affect profitability. Excessive gas input is costly because of high gas prices and comressing costs. Inefficient gas allocation in a field with limited gas availability also reduces profitability. To alleviate the problem of excessive gas usage, an economic slope that relates liquid production and gas injection to cost and profit has been developed. To resolve the problem of gas allocation in a field with limited gas, a method to allocate gas to wells efficiently under this situation is presented and a step by step procedure is given. An example problem consisting of a six-well field is solved to illustrate the procedures presented. 8 refs.

Overview of Artificial Lift Systems

This paper gives guidelines to assist in the selection of artificial lift methods. The most important guideline is determination of the flow rates possible by each method. This requires preparation of pressure/flow rate diagrams combining well-inflow performance relationships with tubing intake curves. The tubing intake curve includes pressure loss in the complete piping system and/or pressure gains by the pumping method. Many other factors other than rate, such as location, retrievability by wireline, corrosion, paraffin, scale deposition, cost, operating life, and others, influence the final selection of lift equipment.

A New Concept in Continuous-Flow Gas-Lift Design

The importance of the differential pressure at the point of injection in continuous-flow gas-lift design is discussed. The role played by differential pressure in the selection of optimal flow in gas lift is also explained. It is shown that good wells with high productivity have continued increase in production as the differential pressure decreases. Weaker wells with low productivity, however, are less sensitive to the change in differential pressure. Also, a concept of error envelope surrounding the point of gas injection is presented. Suitable valve spacing in this error envelope is shown to offset any errors in locating the depth of injection caused by errors in the multiphase flow correlations or in the well productivity. The maximum valve spacing within the error envelope is shown to be directly proportional to the differential pressure. The smaller this differential pressure, the smaller the valve spacing.