Developing Heavy Oil Fields By Horizontal Well Placement - A Case Study

Naganathan, Sivaraman (Schlumberger) | Li, Pan You (CNPCIS,Sudan) | Hong, Luo Hui (CNPCIS,Sudan) | Sharara, Abdul Mageed (CNPCIS,Sudan)


Fula is a heavy oil field located in Muglad basin in Sudan. Aradeiba reservoir in the field consists of highly heterogeneous sandstone that is thinly bedded, unconsolidated, bearing typical heavy oil. Bentiu reservoir is composed of massive sandstone, unconsolidated and traped very high viscous oil. Production performance of vertical wells indicates that the reservoirs are facing problems of low productivity, bottom water conning and sand production. In his circumstance CNPCIS set itself a daunting task of tripling the production in less than a year.

Horizontal wells were considered as best option for improving the productivity in this small to medium sized heavy oil field, and controlling the sand production due to low drawdown pressure and increased exposure the reservoir.

This paper discusses about comprehensive geological study , identification of target oil pools, well design, selection of fit for purpose technologies and the complete well placement cycle including detailed analysis on the drilling and steering challenges while placing horizontal well through reactive shales and channel sand environment.The paper also discusses about various completion strategies , the results of well placement, value of using new technology ,lessons learnt and cost /production analysis.

Team work, communication, knowledge sharing and deployment of fit for purpose technologies has resulted in a five fold increase in production through horizontal wells compared to vertical wells with no sand production. The paper illustrates how integration of different disciplines led to successful well placement, enhanced production with sand and water management in heavy oil environment.