Valeura Energy provides operations update on its Basin Centred Gas Accumulation appraisal programme
Valeura Energy, the upstream natural gas producer focused on appraising and developing an unconventional gas accumulation in the Thrace Basin of Turkey in partnership with Equinor, has provided an operations update concerning its Basin Centred Gas Accumulation (‘BCGA’) appraisal programme.
Highlights
- Devepinar-1 drilled to 4,796 metres with clear indications of over-pressured gas throughout the 1,066 metre gross column in the Teslimkoy and Kesan Formations
- Inanli-1 pressure measurements confirm the well is significantly over-pressured, and the reservoir stimulation and testing programme is expected to commence in late May
- With 11 vertical wells now demonstrating high-pressure gas around the basin, the focus for data acquisition and operations is shifting to continued stimulation and production testing of drilled wells
Sean Guest, President and CEO commented: “We are encouraged by the preliminary results we have seen from drilling and logging Devepinar-1. The data supports our play mapping and confirms that reservoir and over-pressured gas are present some 20 kilometres away from the Yamalik-1 and Inanli-1 wells.
“At this stage, we have nearly a dozen wells across the basin which demonstrate the presence of over-pressured gas and a laterally continuous objective reservoir. This basin is almost a half million acres in size and our recent penetrations have drilled up to a mile of continuous gross gas column. The scale of the resource is significant, and while we have a very good understanding of the basin’s geology and the presence of over-pressured gas, we have as yet only partially stimulated and flow tested one exploration well, Yamalik-1.
“Our near-term focus is shifting squarely to production testing multiple zones across our new wells to understand the gas flow characteristics of our reservoir both vertically and laterally.”
Devepinar-1
The Devepinar-1 appraisal well was drilled safely to 4,796 metres, approximately 500 metres deeper than originally planned due to significant gas shows and faster drilling penetration rates. The top of the objective reservoir was encountered at 3,730 metres and the gross 1,066 metres of the Teslimkoy and Kesan Formations is interpreted to be gas-bearing down to the total depth of the well.
During drilling operations, formation gas was circulated to surface and flared several times, and much of the deep drilling operation was conducted with mud weights in excess of 0.78 psi/ft to manage gas inflow.
The well met all of its drilling objectives and most significantly, confirms the presence of over-pressured, gas-bearing reservoir at the western flank of the mapped BCGA fairway.
The log data and the higher penetration rates both indicate that the porosity at Devepinar-1 is higher when compared to the Inanli-1 and Yamalik-1 wells at similar depths. These results greatly increase the Company’s understanding of the lateral extent of the reservoir and occurrence of over-pressure related to the Company’s basin-wide play mapping.
The Devepinar-1 well has multiple zones of interest with the best zones of interest being located in the upper Kesan Formation, as they were in the previously drilled wells.
High-grading of potential intervals of interest is now underway, in advance of developing a reservoir stimulation programme, jointly with the company’s partners.
The well was operated by Valeura, with costs shared proportionately based on the working interest share of each partner (Valeura 31.5%). Despite the well being drilled deeper than anticipated, drilling and logging operations were conducted below budget. The well is currently being cased and will be left in a state ready for testing and completion.
Inanli-1
The Inanli-1 completion programme commenced with a diagnostic fracture injectivity test (‘DFIT’) to confirm high downhole pressures interpreted from mud weights during drilling. This is a critical step to ensure, among other things, surface equipment for the completion programme is appropriately pressure-rated to ensure safe operations.
The lowest DFIT at 4,813 metres confirms a pressure gradient of 0.809 psi/ft (significant over-pressure), in line with observations made at Yamalik-1.
A second extended DFIT is currently being conducted on a specific completion zone to establish formation fracture stimulation parameters and pore pressure prior to commencing reservoir stimulation operations. In accordance with the DFIT results, suitable equipment rated for up to 15,000 psi has been sourced internationally and is being imported to Turkey.
The company anticipates all equipment will be on site for the first fracture stimulation operations later in May 2019.
The overall goal of the Inanli-1 completion programme is to selectively test key intervals in the approximately1,600 metre reservoir section and to provide definitive, longer term flow results for each interval. Given the significant vertical interval, the completion has been tailored to test the deepest naturally fractured intervals (initial zones to be completed) to the shallower sweet spots (later in the programme).
The programme is designed to include up to 10 fracs in as many as five separate flow zones and will incorporate more sophisticated flow tracing and longer flow periods than the Yamalik-1 completion. In service of this longer test programme, the Company has constructed a pipeline to the location so that gas can be captured through Valeura’s local infrastructure and sold to customers.
The costs for the Inanli-1 stimulation and testing will be fully carried by Equinor and will complete their earning obligations under the Banarli farm in agreement.
Source: Energy-pedia