Decommissioning and abandonment comes with its share of unexpected surprises, but many of those surprises could be avoided merely through better planning and care. The next big wave of decommissioning and abandonment projects is set to occur in the Asia-Pacific region, and APAC’s operators are now tasked with finding cost- and time-effective ways of unwinding their huge agglomeration of wells and facilities. The outlook in the UK is a case study of the squeeze facing E&P in other basins where operators are trying to pay to sustain production with discoveries, while plugging and abandoning old wells, all paid for by the lean cash flow due to low oil prices. From its record high in 2014, purchases of subsea equipment and SURF fell around 50% until reaching a low in 2018. New data suggest that the subsea market will be a top-performing oilfield service segment.
Ashtead Technology has acquired Louisiana-based subsea equipment rental and cutting services specialist, Aqua-Tech Solutions, as part of the company’s international growth plans in the US. Companies in the petroleum industry, from exploration and production, to transportation, refining, and distribution, operate around the clock. This paper intends to raise awareness on the impact of fatigue in the petroleum industry and recommend a framework for fatigue risk management. BP and partners have sanctioned the Azeri Central East project, the next stage of development of the giant Azeri-Chirag-Deepwater Gunashli oilfield complex in the Azerbaijan sector of the Caspian Sea. Coal remains the biggest challenge to LNG in Asia. Decommissioning and abandonment comes with its share of unexpected surprises, but many of those surprises could be avoided merely through better planning and care.
The startup of a second FPSO will add 115,000 BOPD to the deepwater project offshore Angola, bringing overall production capacity to 230,000 BOPD. Commissioning is complete and Bechtel has turned over care, custody, and control of Train 1 to Cheniere, It's the first liquefaction train placed into operation in a greenfield facility in the lower 48 states. Current production from the phase is 400 MMcf/D and expected to peak at 700 MMcf/D. A third phase also is slated to come on stream this year. McDermott will provide EPC, hookup, and commissioning of the Cassia C topsides, a jacket, and a bridge to link Cassia C with the existing Cassia B platform.
BP and partners have sanctioned the Azeri Central East project, the next stage of development of the giant Azeri-Chirag-Deepwater Gunashli oilfield complex in the Azerbaijan sector of the Caspian Sea. This digital deal is helping to make augmented reality a new reality for oil and gas operations. Called Eelume, the underwater drone will perform subsea inspection, maintenance, and repair work. McDermott will work exclusively with Zamil Offshore to provide Saudi Aramco with maintenance, modifications and operations services. A newly launched JIP aims to bridge the BSEE and API frameworks and achieve industry consensus on the analysis and inspection data required to assess the feasibility of an extended service life.
Cedeño, Freddy (Halliburton) | Deen, Larry (Halliburton) | Martinez, Juan (CARDON IV) | Rojas, Ybrendiz (CARDON IV) | Martinez, Valentina (CARDON IV) | Plazola, Pedro (CARDON IV) | Segatto, Michele (CARDON IV) | Martinez, Ricardo (CARDON IV)
The Perla-7 well experienced lost circulation while drilling the naturally fractured carbonate reservoir. To cure the losses, 285 bbl of various lost-circulation materials (LCMs) were pumped. This plugged the 300-micron slotted liner and resulted in an impairment of production. This paper describes a study of the solids retention by a 300-micron slotted liner and the design, testing, and application of a delayed-release acid system to remediate the plugged well and recover productivity.
The well was closed while spotting the delayed-release acid treatment; gas was filling the well from the previous well testing. Coiled tubing (CT) was used along with a proven fluidic oscillator technology that enables better control when matching fluid rates to the most desirable frequency and amplitude of the pressure pulses. When the pressure began rising from the last recorded surface pressure, the well was bled off on the surface to maintain a balanced condition. After the treatment, the well was opened and cleaned out using well testing equipment, flaring hydrocarbons, and spent acid.
Logistical considerations resulted in the selection of the in-situ acid-release system instead of conventional treatments. The pumped LCMs dissolved successfully, helping to swiftly recover well productivity. The acid-release treatment was split into two stages, with a 30-minute soaking time between the pumping of the two designed engineered pills. A total of 270 bbl of the delayed-release acid were pumped at a 25% volume/volume concentration. No special tanks were necessary for this operation; the acid-release treatment is neutral on surface and is easily handled until required. The well test interpretation was developed based on a pressure buildup period before and after the treatment. The results returned a fairly good reservoir property, with a Kh of approximately 10 000 md-ft with a consistent skin reduction from 14 to four. There was also a corresponding reduction in the drawdown of 120 psia, which was necessary to achieve the same gas rate of 50 million scf/D.
The Perla field is the largest offshore gas reservoir discovered to date in Latin America. The Perla-7 well was drilled in the Cardon IV block, located in the shallow water eastern part of the Gulf of Venezuela. The in-situ acid release treatment is now an alternative option through which to support offshore operations where logistics can be challenging, especially when well remediation is required.
The early integration of geological concepts and seismic (qualitative and quantitative) interpretation is a powerful tool to enhance the probability of success of an appraisal campaign. The presented example of an integrated workflow was applied to Perla Field (offshore Gulf of Venezuela), an Early Miocene carbonate reservoir containing gas and condensates. The work was therefore tailored on the integration of geological data and advanced seismic interpretation since exploration project start-up is a key to improve success of appraisal campaign and early production phases.
The presented case refers to an Early Miocene gas-bearing carbonate asset, Giant world-class reservoir. 3D Seismic data shows an isolated bank developed on basement high, thickness decreasing from crest-to-flanks. Wildcat well found 200m high-porous bio-GRST/PKST having moderate diagenetic imprint.
The red algae-dominated system formed low-angle ramps more than classical flat-top platforms. AVO attributes (Gradient) fully supported detailed seismic interpretation, since Carbonate reflections responded to elastic changes rather than subtle acoustic contrasts, negligible on conventional seismic. A petroelastic model and strict quantitative amplitude reliability were validated.
Acoustic Seismic inversion was performed right after the wildcat well.
Efforts devoted to realistic a-priori model building accounted for overburden trend and carbonate sequences velocity fields. The inversion results permitted seismic to effective porosity calibration (Seismic Pseudo-Porosity Volume), a significant tool for the delineation campaign.
Inversion properties vs depositional facies geometries relationships also allowed facies belts areal definition; jointly with structural attributes they were used to optimize the number, locations and trajectories of delineation wells. Appraisal wells confirmed the porosity predictions at seismic scale, and approach stability. No needs for acoustic inversion or calibration revision were considered, due to the high-quality blind tests results on appraisals. The availability of hard-data from extensive core campaign, re-enforced the geophysical calibration to reservoir facies, via petrophysics and rock-physics lab measures.
Seismic Porosity, Non-Supervised, and Supervised Facies cubes got into reservoir model, driving the areal distribution of Sw and K.
Elastic-Porosity large variability was tentatively correlated with the factor Gamma-K, representing the frame flexibility, hence pore structure of different sed-petro-facies.
Manipulation of Elastic Inversion data and more stable Rock Physics Model would be the next development to capture internal reservoir model microstructure variances.
The comprehension of the fracture network at different scales is mandatory for understanding and developing a sub-surface fractured reservoir. The different scales of fractures are investigated using several approaches and then integrated in the final fracture distribution model.
For example the micro-fractures (from cm to meter length) are analyzed, for characteristics and distribution, from oriented cores and well logs, instead faults (macro-fractures, more than hundred meters length) are interpreted and mapped from seismic. The meso-fractures (tens to hundred meters length) are the most problematic since it is impossible to analyze them with direct tools as they are hard to be detected and described in the seismic volumes. This type of fractures, also called sub-seismic fractures, is extremely important for fractured reservoir permeability characterization.
We have developed a workflow which integrates data from analogous outcrops/cores and an automatic detection of structural features in seismic volumes enhanced by attributes as continuity or positive/negative curvature.
The seismic attribute volume is scanned and lineaments are detected and collected. The resulting dataset is statistically analyzed for length distribution (histograms), for strike (rosette diagrams and fracture sets detection) and for density (P21 and P20 maps or 3D grids).
The comparison with the fault network coming from seismic interpretation allows the detection of different fractured domains or fractures corridors related or not to the faults and to better constrain the structural evolution of the studied reservoir.
It is also possible to use these lineaments to compute probabilistic fracture surfaces that can be easily imported in a DFN (Discrete Fracture Network) model for the reservoir characterization.
The results are finally checked taking into account the stress/strain evolution through time of the studied area.
This workflow was successfully applied on the main fractured reservoir operated by eni as: Kashagan field (Kazakhstan), Perla field (Venezuela), Val d’Agri field (Italy).
The description and detection of the real fracture network in a sub surface reservoir is an extremely complex task as it isn’t possible to use a direct and unique approach. The fractures network is always related to the interaction of fractures and faults of different scales (from millimetric to kilometric scale) not uniformly distributed in the rocks volume. There are different and well known approaches to investigated fractures at each particular scale: for example the micro-fractures (from cm to meter length) are analyzed from cores, oriented or not, and well image logs, instead faults (macro-fractures, more than hundred meters length) are interpreted and mapped from seismic. Nevertheless there is a problematic scale to be investigated: the meso-fractures (tens to hundred meters length). It is impossible to analyze them with direct tools as they are hard to be detected and described in the conventional seismic volumes. This type of fractures, also called sub-seismic fractures, is extremely important for fractured reservoir permeability characterization.
The final fracture network models must be reached by the integration of all the available analysis and approaches, at the different scales, with any other useful information about geology, drilling and reservoir engineering. So integration is the only possible solution to the fracture network characterization problem.
We have developed an integrated workflow for collecting all the available data and approaches and to characterize the final fracture network. This workflow essentially focuses on the sub-seismic fracture detection and characterization. Here we present mainly this last point.