Burgan Multilateral Campaign: A Success Story in Development of a Complex Siliciclastic Reservoir in Kuwait
Authors: Ahsan Mohammad Javed , Al-Humoud Jamal , Al-Ajmi Hussain Zuyed , Ghosh Dipankar D. , Datta Kalyan , Chimmalgi Vishvanath Shivappa , Gazi Naz H. , Haryono Rafiq , Kotecha Rohit Kumar , Gupta Biswarup , Al-Anzi Bashar Khallaf 
Published: May 2016

The multilateral well technology was used for the first time in Albian Third Sand reservoir of the super-giant Greater Burgan Field of Kuwait. The reservoir is on production for more than 60 years with conventional development techniques. The multilateral drilling technology was adopted particularly for exploiting the heterogeneous and complex units within Third Sand Upper member of Burgan Formation.

The Third Sand Upper (3SU) unit came up as the right candidate because of its low thickness, relatively poor reservoir quality and inconsistent occurrence rendered it difficult to exploit by conventional wells. On the contrary the more prolific Third Sand Middle unit (3SM), was not considered for multilateral drilling because of its massiveness and hydrodynamic connectivity. Nodal Analysis results suggested comingled production from 3SU and 3SM as not suitable, because of high pressure differential and permeability contrast.

The 3SU was deposited in a broad transgressive set up. As expected in such transgressive units, the sands are thin, heterogeneous and discrete in nature. Paleogeography and sand thickness maps helped in understanding the geometry of the sand bodies for suitable placement of the laterals. A pre-drill model was built based on the logs of the nearby wells to predict the facies in the laterals.

Two stacked bilateral wells were drilled to drain different layers in two separate locations. Multilateral TAML-4 level was selected for adequate junction stability and options for possible re-entry. The lateral length varied from 650 to 1663 ft depending on the spatial distribution of the sand bodies. Effective geosteering through 5 to 10 ft thick sand layers in these wells encountered 0.5 to 1.5 Darcy reservoirs. These thin, discontinuous layers produced about 3000 to 5000 BOPD on production testing, thereby increasing the expected productivity six fold compared to vertical wells.

The success obtained in producing from these thin, heterogeneous and otherwise under exploited reservoirs will open up new fundamentally different and improved development opportunities

Introduction

The Greater Burgan Field located in Southeast of Kuwait (Figure 1) is a north-south trending anticline, and covers an area of about 450 square mile. It consists of three three major fields, Burgan, Magwa and Ahamdi with hydrocarbon contained in three major reservoirs namely Wara, Burgan and Maudud (Lower Cretaceous) and two minor Jurassic carbonate reservoirs Minagish and Marrat (Figure 2). The Burgan field was discovered in 1938 and went on production in 1946. The first wells drilled in Magwa and Ahmadi were in 1951 and 1952 respectively. The Greater Burgan Field is the world's largest siliciclastic oil field which is on production for more than 60 years. In Greater Burgan Field, the principal producers are the Burgan and Wara reservoirs. Its primary producer is the Third sand middle 3SM unit which contributes a major part of the total field production.