Successful Exploitation of Khuff-B Low Permeability Gas Condensate Reservoir through Optimized Development Strategy

Rahim, Zillur; Al-Anazi, Hamoud; Al-Kanaan, Adnan; Aziz, Azly Abdul

doi:10.2118/136953-ms

Cited by 12 publications

(1 citation statement)

References 2 publications

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“…Consequently, well placement was not an easy task to avoid wet zone and enhancing water encroachments [3][4] . The seismic maps (impedance values) show the variability in the reservoir, which is usually thin, up to 20 ft true vertical depth (TVD).…”

Section: Reservoir Heterogeneitymentioning

confidence: 99%

Effective Strategies in Development Heterogeneous Gas Condensate Carbonate Reservoirs

et al. 2010

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A gas bearing carbonate reservoir has been under development in Saudi Arabia to exploit the nonassociated gas to meet the robust increase in gas demand. Initial penetrations showed reservoir heterogeneity with several gas-water contacts (GWCs), variation in reservoir pressure, presence of faults/channels, and H 2 S content and condensate yield. All these factors made it hard to meet the target developmental plans with conventional reservoir exploitation techniques. Therefore, several delineation wells were initially drilled to assess reservoir boundaries and resulted in an upside potential increase in reserves. Gas producing wells were placed based on calibrated 3D seismic impedance and simulation runs. Several strategies have been used to drill these wells targeting the best reservoir development, such as dual lateral, geosteering, horizontal and extended reach wells. Other technologies like multistage horizontal fracturing and underbalanced coiled tubing drilling (UBCTD) were so effective to enhance the wells' productivity from poorly developed and tight reservoirs. One main obstacle was to drill wells in populated areas and finding a more reasonable surface location that provides the most cost-effective drilling operations. This paper will address all these challenges been faced during the initial field development and the technologies and methodologies been used to achieve full field development and meeting the target gas production. Several field cases will be discussed in detail covering geological interpretation, simulation runs, drilling/completion operations, stimulation, production performance, and reservoir management. These strategies were found so effective in developing this gas field, that they are currently being implemented in other fields that will be put on production during the incoming business plan cycle. These strategies helped to confirm field boundaries, identify multiple GWCs, avoid areas dominated with water encroachment, optimize reservoir depletion, and extend production plateau.

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Section: Reservoir Heterogeneitymentioning

confidence: 99%

Effective Strategies in Development Heterogeneous Gas Condensate Carbonate Reservoirs

et al. 2010

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Successful Implementation of Horizontal Multi-Stage Fracturing Enhanced Gas Production in Heterogeneous & Tight Gas-Condensate Reservoirs: Case Studies

Al-Anazi

Abdulbaqi

Habbtar

et al. 2012

Abu Dhabi International Petroleum Conference and Exhibition

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Heterogeneity and tightness of carbonate retrograde reservoirs are the main challenges to maintain gas well productivities. The degree of heterogeneity changes over the field and within well drainage areas where permeability decreases from few millidarcies to less than 0.2 md. Thorough studies have been conducted to exploit these tight reservoirs and not only focused on well performance, but have extended to assure enhancing and sustaining gas productivity through practical applications of technologies. The main objective of this paper is to assess the performance of Multi-Stage Fracturing (MSF) in horizontal wells that were drilled conventionally and did not meet gas deliverability expectation. This paper gives a detailed analysis of well performances, exploitation approaches, and successful implementation and optimal cases to utilize new completion technologies such as horizontal multi stage fracturing to revive low producing gas wells due to reservoir tightness. Placing the horizontal wellbore reference to the stress directions plays a major role in the success and effectiveness of fracturing in enhancing and sustaining productivity. Several wells have been drilled in tight reservoirs, but could not achieve or sustain the target gas rate. Recently, two wells were geometrically sidetracked targeting the development intervals based on logs of the original hole and completed with MSF toward the minimum stress direction. Open hole logs showed a low porosity development similar of the vertical holes. However, after conducting multiple stages fracturing, both wells produced a sustainable rate of more than 25 MMSCFD that prompted to connecting them to gas plants. Placing these sidetracks in the minimum stress direction helped to create transverse fractures that connect to sweet spots and sustain gas production. This paper provides thorough guidelines for selecting optimal candidates for MSF based on reservoir heterogeneity, proper design and execution of fracturing. It also addresses various components that contributed to the success of both wells, such as reservoir development, workover preplanning, geo-mechanics studies, drilling operations and real-time support, completion operations optimization and best-practices, and performance evaluation of other producers in the field. The paper also includes essential recommendations for development of tight gas reservoirs.

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Multistage Acid Fracture Effectiveness in Gas Production in the Carbonate Reservoir, Saudi Arabia - Study and Analysis of Field Examples

Islam

Rahim

Al-Anazi

2015

SPE Middle East Oil &Amp; Gas Show and Conference

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For last few years, multistage acid fracture treatments have become a common practice to develop the carbonate gas reservoirs in Saudi Arabia. Different multistage completions systems have been used in more than 50 wells that were acid fractured anywhere from 2 to 6 stages per lateral. These systems include multistage fracturing (MSF) with openhole frac sleeves in combination with open hole hydraulic or swellable packers to provide zonal isolation between fracture stages. This paper provides an analysis of the effectiveness of these fracturing treatments comparing the pre-and post-frac gas production rates of the wells as functions of fracture half-length, conductivity, and some of the main reservoir properties such as porosity and flow capacity.One major concern from the open hole MSF treatments is the zonal isolation provided by the open hole packer assemblies. This is very important to ensure fracture containment for the zone the induced fracture is intended for. Failure in isolation can lead to communications between intervals allowing the pumped frac stage to propagate to the previously opened frac stage. This could result in fracturing less number of stages than designed. Consequently, the expected production rate may not be achieved. This study also analyzes the post-frac pressure build up response for selected carbonate reservoir wells to compute number of effective fractures created during the treatment. The reason of isolation failures and how to avoid that in the future MSF treatments are discussed in this paper. Several field data including post-frac production data have been analyzed for MSF acid fracturing in the carbonate gas reservoirs to establish the treatment effectiveness. This analysis will be useful to optimize the future well stimulation programs and improve gas production.

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Successful Exploitation of Khuff-B Low Permeability Gas Condensate Reservoir through Optimized Development Strategy

Cited by 12 publications

References 2 publications

Effective Strategies in Development Heterogeneous Gas Condensate Carbonate Reservoirs

Effective Strategies in Development Heterogeneous Gas Condensate Carbonate Reservoirs

Successful Implementation of Horizontal Multi-Stage Fracturing Enhanced Gas Production in Heterogeneous & Tight Gas-Condensate Reservoirs: Case Studies

Multistage Acid Fracture Effectiveness in Gas Production in the Carbonate Reservoir, Saudi Arabia - Study and Analysis of Field Examples

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