This paper will describe a methodology which has been developed as an alternative to four-dimensional (4D) Seismic. The main objective is to track heat conformance over time in the thermally developed "A" Field, Sultanate of Oman. The method has several significant advantages over 4D Seismic, including: Negligible cost and manpower requirements; Provision of close to real-time information and no processing time requirements; No Health, Safety or Environmental exposure, or disruption to ongoing operations.
Negligible cost and manpower requirements;
Provision of close to real-time information and no processing time requirements;
No Health, Safety or Environmental exposure, or disruption to ongoing operations.
The paper will also demonstrate the power of integrating wide-ranging data sources for effective well and reservoir management.
The increasingly close well spacing at "A" Field has made Seismic Acquisition progressively more challenging. Conversely, it has created an opportunity to utilize dynamic Tubing-Head Temperatures (THTs) for tracking areal thermal conformance over time. For each month in turn an automated workflow:- Grids the monthly THT averages; Integrates the production and injection data, represented as bubble plot overlays; Adds the top reservoir structure from the subsurface model, highlighting structural dip, and fault locations.
Grids the monthly THT averages;
Integrates the production and injection data, represented as bubble plot overlays;
Adds the top reservoir structure from the subsurface model, highlighting structural dip, and fault locations.
Morphing (movie) software then interpolates the monthly images to create a smoothly transitioning "Heat Movie".
The Heat Movie demonstrates the general effectiveness of the Development in terms of warming the reservoir over time. This in turn is reducing the oil viscosity and increasing production. However, it also highlights temperature anomalies that can be linked to geological features such as faults and high permeability layers. Identification of these anomalies may underpin decisions to optimise the thermal development.
In addition to the Movie, time-lapse images can be created for any chosen period. This is similar to 4D Seismic, but more powerful, since the period can be directly linked to significant field milestones, for example equal time periods before and after upgrading the steam generation process.
Proof of Concept was demonstrated in early 2018, and the technique has already been deemed sufficiently mature to utilize it for tracking and managing Thermal Conformance in place of 4D Seismic. This is resulting in annual cost savings of millions of dollars and man-years of staff time.
One potential advantage of 4D Seismic is highlighting vertical conformance. Although this is not possible using THTs alone, at "A" Field the plan is to mitigate this by integrating data from ongoing Distributed Temperature Sensing (DTS) and well temperature surveys.
Regarding applicability, the workflow can be adapted for other objectives, for example creating a movie of surface uplift and/or subsidence integrated with bubble plots of production and injection data, or water breakthrough for wells with downhole gauges, in water flood developments.
In addition to describing the methodology underpinning this innovative approach, this paper will also discuss the vision for further improving the workflow and expanding the functionality.
Al Shoaibi, S. (Petroleum Development) | Kechichian, J. (Petroleum Development) | Mjeni, R. (Petroleum Development) | Al Rajhi, S. (Petroleum Development) | Bakker, G. G. (Petroleum Development) | Hemink, G. (Shell Global Solutions International B.V) | Freeman, F. (Shell Global Solutions International B.V)
Fiber Optics Distributed sensing technologies are evolving in the petroleum industry with its potential applicability in many areas of surveillance. Petroleum Development Oman (PDO) is embarking upon the implementation of this technology in various assets including both Gas and Oil fields. The vision of the company is to have the Fiber Optics distributed sensing technology as a surveillance tool in the Well and Reservoir Management (WRFM) toolbox and to become, where appropriate, a key element of its cycle. In comparison to conventional surveillance, fiber optic distributed sensing requires no well intervention and thereby reducing HSSE exposure and production deferment. In addition, the installed fibers can be used for multiple applications, e.g. hydraulic fracture performance monitoring and inflow performance monitoring. Recently, PDO trialed Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS) technologies utilizing both, dip-in surveys and permanent installation of fiber optics in the wells.
Fiber optic implementation in PDO included a polymer flooding trial in heavy oil, high permeability clastic reservoir with a strong bottom water aquifer drive. The objective was to monitor well conformance as the polymer injection progressed. The horizontal injectors were completed with pre-drilled liner and divided into four zones, each with an independent Inflow Control Valve (ICV). The well was completed with a multi-mode (MM) fiber pumped into control lines three injectors. Real time DTS data was acquired continuously in all three wells while DAS was acquired as per the injection program in one injector. DAS and DTS data were analyzed to quantify the changes in injection profile and rate in each ICV zone. This provided timely information needed for decisions related to manipulation of the ICV valves to ensure best utilization of the polymer.
Another example of fiber optics was a dip-in survey in a deep gas well with commingled production which covered stacked reservoirs. This was run in order to prove the concept of flow response on DAS/DTS signals in terms of gas flowing and liquid lifting detection. The acoustic signature observed was mainly due to gas entering the well through perforations. This was detected by DAS and DTS and allowed a qualitative inflow profile to be generated. The dip in survey proved the concept and allowed justification for the permanent installation of fiber optics behind casing. The objective of the permanent setup is to improve the sensitivity of the measurement and allow for better quantification of inflow per zone. In this paper, the approach of implementing fiber optic technologies in PDO is discussed with emphasis on value generation in the various assets. Additionally, the examples mentioned in this abstract are discussed in more details and based on the results, the way forward is described.
Buhassan, Shaker (Saudi Aramco) | Halder, Surajit (Saudi Aramco) | Tammar, Hassan (Saudi Aramco) | Beheiri, Faisal (Saudi Aramco) | Ahmed, Danish (Schlumberger) | Brown, George (Schlumberger) | MacGuidwin, Jeffrey Thomas (Schlumberger) | Haus, Jacques (Schlumberger) | Moscato, Tullio (Schlumberger) | Molero, Nestor (Schlumberger) | Manzanera, Fernando Baez (Schlumberger)
During the last 5 years, one of the most common matrix acidizing enhancement techniques used to improve zonal coverage in open hole or cased hole wells is conducting a distributed temperature survey (DTS) using coiled tubing (CT) equipped with fiberoptic and real-time downhole sensors during the preflush stage before the main stimulation treatment. This is used to identify high and low intake zones so the pumping schedule can be modified to selectively place diverters and acidizing fluids with a high degree of control. Once stimulation treatment has been completed, a final DTS analysis is performed to evaluate the zonal coverage and effectiveness of the diversion. Even though this technique has provided satisfactory results, alternative methods providing faster and more accurate understanding of flow distribution between the zones and laterals are needed, especially if there is limited temperature contrast between fluids and reservoir. Thus, an innovative coiled tubing real-time flow tool has been recently developed to monitor flow direction and fluid velocity. This measurement is based on direct measurement of the heat transfer from the sensors to the surrounding fluid using a calorimetric anemometry principle. The first worldwide use of this technology in a Saudi Aramco injector well showed this to be a viable new approach to downhole flow monitoring that can be used by itself or in conjunction with DTS, depending on the constraints of each individual intervention.
The appropriate inflow control valve (ICV) design plays an important role for achieving adequate proactive reservoir management, production management and improving oil recovery. The smart completion consisting of custom designed inflow control valves along with downhole gauges are proven to be the great tool for maximizing sweep efficiency in Minagish Field, West Kuwait. The demonstrated benefits include reduction of unwanted water production, equalization of inflow profile, elimination of cross flow across laterals in multilateral wells and optimization of water injection allocation resulted in increasing sustained well productivity and maximizing oil recovery. Further the downhole gauges provides required reservoir surveillance data on real time for effective reservoir and production monitoring. Moreover the real time surveillance and production control capabilities over entire well life enabled ability to take necessary actions at right time for facilitate defensive as well as proactive reservoir management. In addition the intelligent wells are proven to control the distribution of oil, water and gas in a well between different layers, compartments or reservoirs having high degrees of anisotropy and heterogeneity.
The smart completions having optimally designed downhole inflow control valves are implemented in oil producers, water injectors, multilateral wells with ESP (Electrical Submersible Pump) and smart dump flood water injectors in Minagish Field. An integrated novel workflow is developed and multi-disciplinary team approach was followed for planning and design of smart completions by considering reservoir properties, geological data, petro-physical data and related uncertainties. Further the various production scenarios, well management scenarios, reservoir dynamics, reservoir uncertainties and reservoir management objectives were considered to select the most appropriate flow trim design of multi-position inflow control valves for wells having multi-zone intelligent completion, smart multilaterals and smart dump flood completions. Also, the right flow control option is included in well design, as it has an impact on the number of zones/intervals that can be realistically controlled in one well, and may affect the overall reliability of the integrated system.
Previous field experiences have shown that the resulting benefits are diminished when the front end engineering does not considered suitable inflow control valve design and choke setting tailored to reservoir requirements and inherent uncertainties. The consequences of poor inflow control valve design is realized and found that only few choke positions are usable resulting in non-optimum well performance. Lessons learned from previous wells were incorporated in the new smart wells design and integrated workflow is developed by including the reservoir properties, reservoir dynamic response (e.g. water encroachment and time to breakthrough) and well operating constraints. The paper covers a novel workflow for inflow control valve design and chokes setting stepping distribution that assimilates reservoir properties, wellbore and production constraints. Also the paper details about established reservoir management and production management achieved by properly designed intelligent completions supported with long term well performance results.
In South Ghawar field, Saudi Arabia, horizontal water injectors have recently dominated conventional vertical wells to increase injection rates and recovery. Most injectors use treated seawater to provide an injection support for Arab D carbonate reservoir with drastic permeability variations, which prevent achieving uniform injection profile and good sweep efficiency.
This paper will discuss a new smart open hole water injection completion system that marks a new era in implementing technology application for the first time in water injection wells to optimize injection and recovery. An integrated technological system that was installed consists of a distributed temperature sensing (DTS) from total depth (TD) to surface, a Permanent Downhole Monitoring System (PDHMS) and 20 inflow control devices (ICDs) with six open hole feed through swell packers.
A fiber optic DTS was used to simulate injection profiling based on mass and heat transfer that was monitored during DTS injection and warm-back data. Moreover, DTS was utilized to optimize and pumping the acid stimulation evenly during the job.
The PDHMS offers unique options for injection regimes, completion integrity, formation properties, and injection assurance effectiveness. The passive ICD system was installed with the purpose to achieve a uniform injection profile for better reservoir management.
In conclusion, applying this new integrated technology application in the world for the first time in a horizontal power water injector (PWI) provides a real-time controlled uniform injection profile, optimizes treatment fluids placement, monitors casing leaks, fluid movement behind casing and the mechanical integrity of the swell packers without a costly well intervention. This in return improved the well's deliverability and efficiency. Actual field data will be presented to validate findings and support conclusions.
The reservoir is a heterogeneous fractured carbonate. Vertical down-dip open hole power water injectors (PWIs) were drilled at the periphery of the field to provide pressure support since 1964. Due to the remoteness of these wells to producers and closeness to the aquifer, they were less efficient. Therefore, up-dip open hole horizontal PWIs with high injection rate potential were drilled a few years ago for more efficient injection support.
The moving of the PWIs up-dip in the highly fractured reservoir poses challenges to prevent premature water breakthrough at the producers and consequently occurring poor floodfront advancement.
An advanced well completion (AWC) was deployed in the first PWI as a field trial test to distribute injection across the entire open hole horizontal interval evenly, obtain real time compartmental injection profiling and eliminate the need for horizontal flow meter logging and well intervention. AWCs consisting of passive inflow control devices (ICDs) with water swellable packers to create open hole compartments in the reservoir combined with a DTS system that was deployed and attached to the tubing from the surface to a total depth (TD).
Novel modelling technologies that includes induced fractures in a dynamic reservoir simulator has been used to analyse subsurface aspects of an inverted 5-spot injection pilot. The techniques have allowed an accurate depiction of growing induced fractures. Simulation results indicate that induced fracture growth is limited at injection rates < 200 m3/d but that higher injection rates will result in fracture propagation and a risk of rapid water breakthrough. The results have been validated by field observations. A controlled and cautious increase in injection rate has resulted in a positive production response with rate increases of 50-100% in three of the four producers in the pilot.
Results from the pilot have increased the current reservoir understanding and reduced subsurface uncertainties. The knowledge gained is being included in an updated Field Development Plan that will be issued in 2005. The plan will incorporate an optimised injection strategy by a careful and controlled ramp up in injection rate. This project has also advanced induced fracture research with a field verification of the predictive capabilities of the modelling technology.
The Marmul Haima West sandstone reservoir in South Oman, containing heavy and viscous crude (22 ÂºAPI, Î¼o = 90 cP) and on production since 1980, was initially developed on depletion/solution gas drive using vertical wells. To boost production and improve recovery, an aggressive waterflood development using horizontal wells was initiated in 1999. The development was, however, stopped prematurely in 2000 after excessive induced fracture growth resulted in water short-circuiting and poor well performances.
To improve subsurface understanding and redefine a development strategy, an inverted 5-spot produced water injection pilot project was initiated in 2002 with the procurement and construction of dedicated water cleaning and injection facilities and drilling of 5 new vertical pilot wells (i.e. wells I-1, P-1, P-2, P-3 and P-4). A map of the field and the placement of the 5-spot pilot have been shown in Figure 1.