Improved oil recovery solution sought in Libya
Horizontal drilling has substantially improved oil recovery rates in
recent years, as incremental oil recovery and production rate can improve
because of less water coning, larger drained area, and higher sweep efficiency.
However, drilling horizontal wells to improve oil recovery can be difficult and
has high associated risk in placing the well and steering within the best
reservoir zone; sometimes, advanced technology methods are required. One such
method is bed boundary detection and mapping using PeriScope service.
The Arabian Gulf Oil Company (AGOCO) was operating in the Messla field
in Libya and wanted to enhance oil recovery in one of its wells in the region.
The company logged a pilot hole and worked with Schlumberger to evaluate the
resulting data as well as develop and deploy a solution that would improve
Optimal attic interval targeted
Schlumberger petrotechnical experts interpreted the pilot log and
delineated the oil column, with results showing a production zone of interest
located below a shaly sand layer, which should be avoided. Results also showed
that the oil column was narrower than initially mapped. Working in
collaboration with AGOCO, the team suggested drilling the top of the reservoir
with the PeriScope service in the drillstring. PeriScope bed boundary mapping
service enables seeing the reservoir top as the well is being drilled, which
helps the drilling trajectory avoid the oil/water contact (OWC) and mitigates
the risk of exiting the reservoir from the top. As a result, subsequent
sidetracking is eliminated and production enhanced.
Petrophysical Comparison of Conventionally Drilled Offset Wells with
PeriScope Service Well
||Offset Well 1
||Offset Well 2
||PeriScope Service Well
|Average water saturation
|Average clay volume
|Average production rate
Production improved with high petrophysical quality
Compared with two conventionally drilled offset wells, the well drilled
using the PeriScope service produced reserves of higher petrophysical quality.
Schlumberger petrophysical interpretation found decreased water saturation and
clay volume, while net-to-gross ratio improved. The 2,385-bbl/d production rate
of the PeriScope service well was much better than anticipated, and water cut
was eliminated. Based on this operational success, the operator expressed
interest in using the bed boundary mapping services on future wells to improve