Experience of IOR Practices from Large-Scale Implementation in Layered Sandstones

Abstract

Abstract Daqing Oil Field has produced more than 11 billion barrels of crude oil and is still producing at a rate of more than one million barrels of oil per day. In its development, it has extensively implemented numerous IOR methods. The results are very good, total oil production from the IOR methods is more than 700,000 barrels oil per day and it has more the doubled the recoverable reserves of the oil-field (from 8 billion barrels to about 18 billion). Also, much has been learned from the above large-scale IOR practiced, some of which are: The major aim of IOR methods is to increase the volumetric sweep efficiency, displacement efficiency and decrease the water cut (on condition that corrosion, sand, casing damage and environmental issues are not major problems in the field). Results of IOR methods should mainly be measured by a) the total incremental recovery and b) the ratio of the increase in recovery to its costs. To obtain good overall results, large scale implementation on most of the wells in a field is recommended. Otherwise, there will be an increase in production in wells but un-significant increase in recovery of the total reservoir;The results of different IOR methods are mainly dependent on the heterogeneity and water cut of the reservoirs and the IOR method used. Numerical simulation predictions are given and compared to the actual field results. The comparison is satisfactory;For stacked reservoirs, besides horizontal drilling, most IOR methods obtained very good results;For single layer reservoirs, besides chemical flooding and horizontal drilling, most IOR methods were not satisfactory;The reasons that selective water plugging at producers and in-depth profile modification at injectors are not satisfactory and challenges that need to be met are put forward;Criteria for the cost of incremental oil by chemical flooding to be higher, equal or lower than water flooding are put forward with actual field data:The reasons that in-fill drilling of single layer reservoirs can increase the production rate significantly and also the recovery slightly is explained with numerical simulation data and actual field examples. The above lessons learnt are all from large-scale implementation and numerical simulation, which makes the conclusions more reliable and should be of reference use in the development of layered reservoirs.