Real-time data acquisition and interpretation needed for optimal
Zhambyl Petroleum is licensed to explore an ultrashallow oilfield block
offshore Kazakhstan in an area of extreme environmental sensitivity. This
required Zhambyl to build a new barge drilling unit to access the field.
The operator chose Schlumberger to perform its first downhole test on
its first exploration well, ZB-1, in the Zhambyl field. The main test objective
was proving production capacity by obtaining representative samples of
reservoir fluid. Considering the rig costs, Zhambyl required that data be
immediately processed onshore concurrently with offshore operations.
Global support and expert collaboration deployed as solution
Schlumberger proposed transmitting real-time data using the InterACT
global connectivity, collaboration, and information service to facilitate data
monitoring and delivery from the well site to the Zhambyl office in Atyrau,
Kazakhstan. All streaming data were visualized as time-scaled plots and as
process-flow diagram panels, including alarm threshold settings. This expedited
data access and quality control and helped onshore Zhambyl personnel to
collaborate effectively with offshore crews and make informed decisions.
Next, Schlumberger suggested using RT Certain real-time test
collaboration with reservoir experts, a service that enables data transmission
as well as provides reservoir engineering support. Through this collaborative
approach, Zhambyl petroleum optimized the well testing sequence by predicting
reservoir and well behavior to ensure interpretable data for reservoir
characterization. By working in a collaborative real-time virtual environment,
the customer was able to evaluate and modify the well test program with
certainty to optimize the data provided from each stage of the test.
The main priority during well cleanup was validating the unloading time
of the well to ensure its effectiveness in saving rig costs. This involved
Zhambyl monitoring the cumulative volume of retrieved cushion to predict the
unloading time and bottomhole pressure, data which was then used to select
choke size to control the time and underbalance within the formation and to
prevent sand production. At the end of cleanup, the optimal main-flow choke
size was determined to help give stable, single-phase flow within the reservoir
as well as to improve pressure transient interpretation.