This paper derivates a method for calculating reasonable well spacing density of low permeable reservoirs through economic evaluation considering drilling investment, surface investment and oil sale income, and the interest of the three.

This paper considers every factor affecting the well spacing density, uses net present value to improve the method for calculating economy rational well spacing density of matured oilfield.

A new method of calculating rational well spacing density in late stage of high water cut;

Analysis on Reasonable Economic Well Spacing Density of Wangchang Oilfield;

Preliminary study of well spacing density for Yuedong heavy oil reservoir;

. Coinputation of economical well density using a trial method;

Based on net present value principle with geological and economic parameters affecting limit well density, a calculation method of economy limit well density was introduced in the paper.

Determination of economic limit for well pattern density of oilfield;

By means of the analysis for the fluid and development characteristics of low permeability oil reservoirs,we have found out the major problems existing as the low well pattern density,less precise development sequence classification,less injection-to-production-well ratio.

Reasonable well pattern density is pivotal decision-making parameter at oilfield development first stage.