Mhemed, Mohamad (Mabruk Oil Operation) | Elrotob, Nagib (Mabruk Oil Operation) | Elsadawi, Abubakr (Mabruk Oil Operation) | Ben Abdalla, Mohamed (Schlumberger Oilfield Services) | Sherik, Ayoub (Schlumberger Oilfield Services)
For two wells, performing continuous N2 lifting in an offshore environment for weeks to produce a large quantity of aquifer water that had crossed into oil-bearing zones during a long shut-in period would involve high operational and logistical risks and require a large capital investment, which was not proven economical. As an alternative, a Rigless coiled tubing (CT) gas lift system, which uses gas cap energy, was chosen as an efficient, reliable, and cost-effective technique to revive oil production from the two offshore wells.
The technique involved running CT inside the production tubing. The CT was then hung up on an additional tubing hanger installed on the production tree. The injection rate and injection pressure were supplied by a choke manifold connected to a gas well that had high wellhead pressure. The gas was injected down continuously through CT, which lifted the standing water in the production tubing annulus to surface. Production logging tools, simulation models, and flow performance applications were used to
Estimate the volume of water crossed into oil-bearing zones Identify the time needed to revive the wells
Estimate the volume of water crossed into oil-bearing zones
Identify the time needed to revive the wells
The CT gas lift system was found to be the most efficient and cost-effective way to revive production from dead wells. In this application, the free available energy of the only gas well in the field, which was drilled in the gas cap, was used to supply the required gas rate and injection pressure.
The following steps were completed with the collaboration of all parties:
Successful installation of CT in production tree via additional retrievable tubing hanger Gas pressure and gas rate supplied and controlled by a choke manifold Real-time support to guide the operation towards success Successful retrieval of CT when the operation was over
Successful installation of CT in production tree via additional retrievable tubing hanger
Gas pressure and gas rate supplied and controlled by a choke manifold
Real-time support to guide the operation towards success
Successful retrieval of CT when the operation was over
As expected, each well took nearly 45 days of continuous lifting to reach the pre-estimated water cut for the wells to be self-lifting. CT was then successfully retrieved, and the wells continued flowing naturally with considerable rates. The oil rate gain for both wells was around 4,000 BOPD.
This methodology has been approved and adopted by the operator for future similar cases as a cost-effective method to revive oil production from dead wells.
The novelty of the technique comes from the utilization of gas cap energy in the form of high wellhead pressure of the only gas well in the field, which was drilled in the gas cap, as a source of injection pressure and injection rate. This innovative technique made reviving dead wells possible without changing wellhead configuration or investing in weeks of costly N2 kickoff operations.
Geostatistical-based models provide a considerable improvement for predictive reliability of dynamic models and the following reservoir management decisions. This study focuses on geostatistical modeling the Paleocene Zelten Carbonate reservoir in the Meghil field. The field was discovered in 1959 and production operations began in 1961. Nineteen wells have been drilled to date. The structural framework consists of three slightly asymmetrical anticlinal structures trending NW-SE with steeper dip on the SW flanks. Each of the structures are separated by major normal faults. Seismic interpretation suggests that carbonate build-ups are most likely present on the three separate structures. Edge detection was used to clarify the structural geometries and the presence of additional minor faults. Pillar gridding technique was used to develop the structural framework including four major faults that are partially sealed based on analysis of the available DST and production test data. Stratigraphic analysis indicates a local presentation of dolomitic limestone in the northern portion of the main and the western structures caused considerable litho-facies variation that impacted the distribution of the petrophysical properties. Basic and advanced formation evaluation the net reservoir thickness of about 15 feet with an average porosity of 17% and average water saturation of 35%. Geostatistical-based applications that combine the spatial statistics (e.g. the semivariogram) and the available well and core data were used to populate the reservoir model with porosity, permeability, facies (lithology), net/gross, and water saturation. A conceptual facies model was also used to constrain the reservoir property distributions. Sequential Gaussian Simulation (SGS) was used to populate the model with porosity and water saturation and Sequential Indicator Simulation (SIS) was used to populate the facies model with permeability. The modeling parameters (e.g. semivariogram, correlation coefficients) were significantly constrained by the limited number of wells. Based on the limited number of wells available the semivariogram analysis resulted in a spherical semivariogram model with major axis range of 1435 meters for porosity and 1800 meters for water saturation. Minor axis ranges were about 50% of the major axis ranges. Given the limited well data, a significant effort was made to document the potential impact of the semivariogram parameters on the original hydrocarbon in place (OHIP) estimates and the lateral stratigraphic continuity of reservoir properties. The deterministic approach resulted in place volume estimates of 60 MMBBL and the stochastic approach provided an estimate of 45 MMBBL.
With the A Peer Apart award, SPE recognizes those dedicated individuals involved in the review of 100 or more papers for SPE's peer-reviewed journals. Peer review is an essential part of scientific publishing and helps to ensure the information published in a journal is well supported and clearly articulated. Volunteers who commit their time to review papers make substantial contributions to the technical excellence of our industry's literature. Each year SPE typically has more than 1,400 individual reviewers submitting more than 3,500 reviews for SPE's various journals. This group of committed volunteers come from a variety of backgrounds, including academia, service and operator companies, and consultants from around the world.
Wei, Chenji (Research Institute of Petroleum Exploration and Development, CNPC) | Zheng, Jie (Research Institute of Petroleum Exploration and Development, CNPC) | Ouyang, Xiaohu (China Petroleum Pipeline Engineering Co., Ltd, CNPC) | Ding, Yutao (China National Oil and Gas Exploration and Development Company Ltd. CNPC) | Ding, Mingming (China National Oil and Gas Exploration and Development Company Ltd. CNPC) | Lin, Shiyao (China National Oil and Gas Exploration and Development Company Ltd. CNPC) | Song, Hongqing (University of Science and Technology Beijing)
Understanding the heterogeneity is critical for a successful water injection in a carbonate reservoir. Thief zone is one of the most obvious forms of heterogeneity, which indicates the thin layer with higher permeability compared to the average reservoir permeability. The existence of thief zone results in earlier water breakthrough and faster water cut increase, which then lead to lower sweep efficiency and smaller recovery factor. Therefore, determining the distribution of thief zone and its impact towards production, and proposing a corresponding development plan are very important.
In this paper, a novel method is established to determine the thief zone distribution based on dynamic surveillance data. A new index is proposed as the relative contribution index to characterize the relative contribution of a certain layer, which is fundamental for thief zone determination. In addition, effect on water flooding development of thief zone's location is studied by experimental and theoretical analysis. The changes of water cut and production rate are analyzed under different conditions such as location of the thief zone, injection rate, and variogram. Finally, optimized development strategy is proposed to deal with the existence of thief zone.
Distribution of thief zone is characterized based on the proposed method, which indicates that thief zone development has intimate relationship with depositional facies and diagenesis. Experimental and theoretical analysis results show that the present model considering stratified water-flood is consistent with the experimental results. The water displacement effect is the best when the thief zone is located in the upper reservoir. This paper also points out the optimal adjustment period for water shutoff and profile control of the reservoir with thief zones. In addition, the greater the injection rate, the faster the water cut increase. Furthermore, the smaller the variogram, the slower the water cut increase, and the later the water breakthrough time.
This study provides a method to characterize thief zone, which can be used as a reference for similar oilfield development. In addition, it provides a quick and reasonable guide in the later adjustment of water flooding development of carbonate reservoirs with thief zones.
This seminar will teach participants how to identify, evaluate, and quantify risk and uncertainty in everyday oil and gas economic situations. It reviews the development of pragmatic tools, methods, and understandings for professionals that are applicable to companies of all sizes. The seminar also briefly reviews statistics, the relationship between risk and return, and hedging and future markets. Strategic thinking and planning are key elements in an organisation’s journey to maximise value to shareholders, customers, and employees. Through this workshop, attendees will go through the different processes involved in strategic planning including the elements of organisational SWOT, business scenario and options development, elaboration of strategic options and communication to stakeholders.
The F field in the Middle East currently has more than 40 producing wells in the center of the structure. The uneven well distribution limits the understanding of 3D reservoir characterization, particularly in the flank areas. A new technique that analyzes scanning electron microscope (SEM) images of formation samples has been used to measure porosity and total organic carbon (TOC) in the Wolfcamp Shale of the Delaware Basin in west Texas.
Two more oil fields in Libya are being closed after an armed group took over pipelines to both deposits, further disrupting the OPEC nation’s plan to boost crude production. Libya halted loadings from its biggest oil field in the latest disruption to the nation’s crude production and shipments. Libya’s biggest oil field, Sharara, is “back to normal” after a disruption caused by protests in the politically fragmented country, the state National Oil Corp. (NOC) said.
Just as Libya resumes oil exports from recently shuttered ports, an attack on its largest field is setting back progress yet again. Oil production at Libya’s Sharara field, the country’s largest, was resuming on 6 September after a valve was reopened on a pipeline shut by an armed group for more than 2 weeks, Libyan oil industry sources said. Two more oil fields in Libya are being closed after an armed group took over pipelines to both deposits, further disrupting the OPEC nation’s plan to boost crude production. Libya halted loadings from its biggest oil field in the latest disruption to the nation’s crude production and shipments. Libya’s biggest oil field, Sharara, is “back to normal” after a disruption caused by protests in the politically fragmented country, the state National Oil Corp. (NOC) said.
Anadarko Petroleum wants a fleet of at least six vehicles with armor heavy enough to stop AK-47 bullets at its natural-gas project in Mozambique. And it needs them soon. By examining two very different security-risk environments, this paper will illustrate how easily security-related human-rights risks can go unnoticed unless care is taken early in the risk-management process. A third Damen security vessel will be deployed to provide security and other support services to the international offshore oil companies active off the coast of Nigeria in the Gulf of Guinea, in cooperation with the Nigerian Navy. Sinopec’s Shengli oil field became the latest victim of the ransomware that hobbled big business across the globe.
When the head of Libya’s state energy company visited Sharara oil field in early July, community leaders and workers crowded into a conference room to ask about jobs, training, and services for local people. Public acceptance is a major challenge for the siting of facilities. The offering of compensation to communities potentially helps to create the perception of a fairer distribution of local risks and nonlocal benefits. This may help to prevent or solve siting controversies. Anadarko Petroleum said late on 30 June that it has tested more than 4,000 active oil and gas lines and plugged another 2,400 inactive ones per a state order issued after a fatal home explosion in Firestone, Colorado, in April.