Abstract
Tengizchevroil (TCO) has been disposing waste water (produced and industrial) into a shallow sand aquifer for almost 20 years. Waste Water Disposal (WWD) Mining Allotment requests waste water to be contained within certain formation stratigraphically and certain "polygon" laterally. TCO is interested in maintaining high injection rates, maintaining well integrity without compromising regulatory restrictions. There were two new wells recently drilled in the area. These two wells have provided excellent opportunity to acquire core and wireline data to improve the reservoir characterization.
Careful planning and preparation of operating procedures for all operations (site preparation, drilling, coring, core handling and analysis, wireline acquisition and petrophysical interpretation) led to a big success of being drilled below budget and ahead of schedule with zero incidents and injury free. Collaborative discussions with vendors on selecting appropriate equipment and pin pointing the logistic details minimized hassle and potential human error during the operations.
Acquired core from key formations of interest, full suite of wireline logs and two water samples in conjunction with seismic greatly improved understanding of the depositional environment, connectivity and areal extend of numerous sand bodies, including main injection sand. Acquired MDT data confirmed the isolation between main injection interval and overlaying formations. Good quality porosity data and MDT pressure information assisted in modeling efforts to achieve more accurate aquifer size estimation and history match existing pressure data. Acquired information will also help designing a production test with electrical submersible pump (ESP) in a future well in this area.
Overall, the value of acquired information exceeded expectations of all final users. The main reason for such a success is the involvement of almost all stakeholders from the well planning to execution. The well program included actions to fulfill regulatory affairs, reservoir management requisites and improve oil recovery (IOR) project needs to evaluate water sources and reservoir quality for future waterflood project.
