Novel Rod-Shaped Proppant Fracturing Boosts Production and Adds Recoverable Reserves in Indonesia During Hydraulic Fracturing Field Revival Campaign
Authors: Soetikno Luciana , Artola Pedro Daniel , Guimaraes Cesar 
Published: May 2016

Field X is a light oil field, situated on Sumatra Island, Indonesia, operated by an operator on behalf of the Indonesian government. The field is a mature base business operation. Although the field has been in production since 1971, the recovery factor is low, with significant recoverable reserves remaining unproduced. Considerable production potential exists, and production needs to be revived through rigorous application of effective reservoir management coupled with deployment of optimized hydraulic fracturing engineering and novel technologies, particularly in the lower-quality reservoirs. This is the case for the shallowest oil zone, the X1 formation, with low recovery factors due to effective permeabilities being lower than 50 md. Over the last few years, hydraulic fracturing has moderately increased oil production from this zone. Through a comprehensive review of the results, the project team identified opportunities to enhance production by increasing fracture performance through augmentation of effective fracture conductivities, effective fracture half-length, and proppant pack stabilities.

In a fracturing campaign of three wells at field X, a new unconventional proppant technology, a rod-shaped proppant, was used. The rod-shaped proppant is a high-strength ceramic proppant with an unconventional rod shape that has the unique benefit of delivering increased proppant pack conductivities, higher and cleaner fracture length, and improved proppant flowback control. The entire engineering process in this campaign involved candidate selection, modified fracture design, treatment execution, treatment evaluation, and the production results for the first three hydraulic fractures executed with rod-shaped proppant in the identified Sumatra reservoirs. A production comparison was made with hydraulically fractured offset wells using conventional proppant. The production increase in wells with the rod-shaped proppant strongly supports the successful implementation of the technology. After 6 months of production, all fractured wells in which the rod-shaped proppant was used delivered, on average, 25% higher oil per net pay compared to offset wells fractured with conventional proppant. Furthermore, although no dedicated proppant flowback technique was deployed in these wells, proppant flowback was avoided because of the proppant interlocking mechanism in the rod-shaped proppant. With this success, there are plans in place for a wider implementation of this technology in field X.

Introduction

Field X is a mature waterflood field in the Central Sumatra basin. Currently, production is approximately 17,000 BOPD; most production comes from formation Y, and a much smaller contribution comes from the shallower, but tighter, formation X1. A reservoir study for further field development of formation X1 in field X was conducted in 1999. Based on this study, it was determined that the recovery factor of formation X1 was low (single-digit recovery). Given this low recovery factor, several options were considered to better develop the remaining reserves. The implementation of hydraulic fracturing was evaluated as one of the options to increase the oil recovery of the reservoir.

Although the peripheral water injection case provided more oil recovery than the others, it was considered too risky to implement because of the complexity of the reservoir and the uncertainty of the injected water movement. In terms of number of wells required and incremental oil recovery, hydraulic fracturing and horizontal wells were regarded as the most promising options for further development of sand X1. Hydraulic fracturing was chosen as the first strategy in producing the remaining oil in sand X1 because it was considered a relatively simple job compared to drilling horizontal wells.