Horizontal Drilling Challenges in the Thin Oil Sands of the Lower Burgan Formation, Kuwait- A Case Study

Abstract

Horizontal drilling technology was used for the first time in the Middle Cretaceous Lower Burgan Layered Sand reservoir of Raudhatain Field, Kuwait for enhancement of oil production. The reservoir has been on production using conventional development techniques for the past 50 years.The channel sands of the Lower Burgan Layered unit were targeted. These sands are much thinner than the world class Lower Burgan Massive Sand and became an ideal target for development by horizontal drilling. However these layered sands are very prolific and are at irreducible water saturation. These sands were de an ideal target for development by horizontal drilling. However these layered sands are very prolific and are at irreducible water saturation. These sands weic and are at irreducible water saturation. These sands were deposited in a clastic coastal environment. The complex geometry and heterogeneity make these sands a real challenge to place lateral boreholes within the sand.The challenge of horizontal drilling through thin sand is to expose significantly more reservoir rocks in the wellbore which helps to increase the productivity.This paper illustrates integration of LWD, geological, geophysical and engineering data for successful placement of the lateral sections within the targeted sands to maximize oil production.In the 1 st phase of horizontal drilling, laterals in 4 wells were placed in the Lower Burgan Layered sands at different locations over the Raudhatain structure. Length of laterals varied from 650 -2000ft depending on the spatial distribution and geometry of sand bodies' vis-à-vis oil column. Effective geosteering through 7-12ft thick oil sands in these wells encountered 0.5 -1.5 Darcy reservoirs. These oil sand layers produced from 850 BOPD to 4500 BOPD on initial production testing.The success obtained in producing from these sand layers proved to be very effective and greatly enhanced the production from Raudhatain Field, Kuwait.