Minagish Field Research Articles

Integration of Seismic Poisson Impedance Data with Real-Time Geomechanics and Real-Time 3D Ultradeep Resistivity Inversion Enabled New Opportunities in Developed Field: Case Study from Kuwait

Summary The Wara sandstone reservoir in the Minagish field of Kuwait Oil Company is a complex deposition of a typical pro-deltaic environment consisting of shaly-silty sandstone sequences, referenced as W7–W1. Three of these sequences (W6, W5, and W3) were expected in the case study well. The objective was to set a 9⅝-in. casing at the top of W6 and then drill through the Wara sequences to connect all of them and land and drill the lateral section within W3. The W6 sequence is typically the primary target in the Wara formation, being thick and consistent throughout the field. The next logical step in developing the Wara reservoir was to study and investigate the minor W5 and W3 members. Due to poor correlation of W5 and W3 channels in offset wells, the geological target was selected based on seismic Poisson impedance (PI). Historically, targeting the Wara formation occasionally resulted in multiple sidetracks due to drilling challenges. A real-time geomechanics service was used to overcome drilling challenges, and real-time 3D ultradeep resistivity inversion was implemented to optimize the well placement. An extensive predrilling study for geomechanical and ultradeep resistivity inversion modeling helped to develop a road map for an optimal and safe well-construction process. The study showed that use of real-time 3D ultradeep azimuthal resistivity (UDAR) inversion would help to optimize the well placement and maximize the sweet-zone exposure. The original well design, mud properties, and drilling parameters were modified based on the geomechanical study. Additionally, real-time geomechanics services were used to monitor and control the drilling process to follow the road map, which helped to avoid drilling issues, geostop at the W6 channel, and finally to run the casing smoothly. Real-time 3D ultradeep resistivity mapping in the lateral section helped the operator to drill through W6 and W5, land precisely, and drill the lateral in the W3 channel, which was well developed, as expected from seismic PI analysis. Formation evaluation of the lateral section showed an average porosity of 24 p.u., water saturation of 11%, and up to 3 darcies/cp mobility. The application of real-time 3D ultradeep resistivity inversion helped to triple the planned formation exposure and discover a geometric extension of the above deposited channels (W6 and W5), which will help for future field development. The flow test showed the highest production rates from W3 in the field. The integrated approach described above was recommended to be utilized for all future Wara wells.

Organic geochemical evaluation of hydrocarbons in Lower Cretaceous Middle Minagish reservoir, Kuwait

Organic petrography and geochemical analyses of 72 core samples from the Minagish Formation revealed vertical variations in oil composition between four wells from the Burgan, Maqwa, Minagish and Umm-Gudair fields. The Burgan Field has a homogeneous oil column while variations in oil column were recognized between fields. The thickest heavy oil column, 46 m, was identified in Minagish Field. GC and GC-MS of the light and intermediate parts of the oil indicates a similar oil type, with a common oil pool in all of the oil fields. Thus, the variation in the nature and distribution of the heavy fractions of the oil in the Minagish reservoir is not be related to the source rock, expulsion and/or oil migration, but related to changes that occurred after or during oil accumulation in the reservoir.The methods and the results of this study are useful for planning drilling specially in reservoirs with heavy oil intervals such as the Minagish reservoir.

Drilling of Multilateral Wells in Kuwait Aided With Geochemical Analysis

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 16617, ’Drilling of Multilateral Wells Aided With Geochemical Analysis, Kuwait,’ by Taher El Gezeery, Abdul Aziz Ismail, Khalaf Al Anezi, Monirah Al Jeaan, Jeevan Kumar Silambuchelvan, and G.S. Padhy, Kuwait Oil, and Atul Wasnik and Ahmed Al Shoeibi, Geolog International, prepared for the 2013 International Petroleum Technology Conference, Beijing, 26-28 March. The paper has not been peer reviewed. The Burgan reservoir consists of vertically stacked channel sands along with a fault network connected to the aquifer and contains highly viscous reservoir fluid. This dramatically enhances the water mobility and results in severe premature water breakthrough, bypassing zones of oil. This paper describes the use of real-time geochemical analysis to support geosteering of a smart multilateral well located in one of the highest-potential-flow areas of Kuwait. Introduction The Minagish field in Kuwait was discovered in 1959 and is located in the southwestern part of the country. It contains several reservoir intervals in its stratigraphic column, varying from Early Jurassic to Late Cretaceous. The field is situated 12 km northwest of the west Umm Gudair field. The field has been penetrated by more than 180 wells, to contact not only the middle and lower Minagish reservoirs of the Lower Cretaceous but also other shallow reservoirs such as the Mishrif/ Rumaila carbonates and the Wara/Burgan sandstone. The Minagish field structure of the Wara and Burgan formations is a closed elongated asymmetrical anticline oriented in a north/south direction. The top of the Burgan structure is located at approximately 5,500-ft true vertical depth subsea. Burgan Reservoir. This reservoir is informally divided into the upper and lower Burgan sections. Lower Burgan sands are more extensive and blocky in nature, with few variations in their properties. The lower Burgan reservoir section lies above the oil/water contact (OWC) and is of significance from a hydrocarbon-bearing perspective. Upper Burgan sands are mainly in the form of channel sands, ranging in thickness from a few feet to nearly 45 ft, and they have extensive lateral facies variation. The lower part of the Burgan has active bottomwater drive, whereas the upper part of the reservoir has an edgewater-drive system. The reservoir contains high-permeability sands on the order of a few darcies associated with active faults and has highly viscous reservoir fluid (approximately 40 cp at reservoir conditions). This heterogeneous nature of the reservoir accelerates water movement inside the reservoir and results in premature water breakthrough in the existing vertical wells and in horizontal wells, in spite of maintaining the highest standoff from the OWC.

Innovative Geosteering Technology in Multilateral Wells

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 24002, ’Innovative Geosteering Technology Used in Drilling Smart Multilateral Wells, Kuwait,’ by T. El Gezeery, A. Aziz Ismael, K. Al-Anezi, G.S. Padhy, Fawaz Al Saqran, A. Abdul-Latif, and J. Silambuchelvan, Kuwait Oil Company, and J. Estarabadi and G. Ferroni, Geolog International, prepared for the 2013 Offshore Technology Conference, Houston, 6-9 May. The paper has not been peer reviewed. Copyright 2013 Offshore Technology Conference. Reproduced by permission. The Burgan reservoir in Kuwait has the potential for premature water breakthrough, leaving behind bypassed zones of oil. The placement and completion of horizontal wells in such reservoirs is a challenge necessitating a collaborative approach from petroleum geoscience, reservoir engineering, and petroleum engineering. This paper describes placement of horizontal wells in this kind of heterogeneous reservoir through an integrated approach. Introduction The Minagish field was discovered in 1959 and is located in the southwestern part of Kuwait. It contains several reservoir intervals in its stratigraphic column, varying from Early Jurassic to Late Cretaceous. The field is situated 12 km northwest from the West Umm Gudair field (Fig. 1). The field has been penetrated by more than 180 wells. The field structure of the Burgan formation is a closed elongated asymmetrical anticline oriented in a north/south direction. The top of the Burgan structure is located at approximately 5,500-ft true vertical depth (TVD) minus the elevation above mean sea level of the depth reference point of the well. Regional Geology. The Burgan formation consists of a lower braided river system with stacked sand bodies. The sediment ranges from fine to medium grain sizes, and the porosities are high enough for lateral migration. On top of the upper Burgan channels, the sediments are generally finer but still retain a fluvial character. The amount of shale is higher. The marsh and tidal sediments, which consist of fine sands, silty sands, and sandy silts, seem to be of lower connectivity for vertical migration. The porosity is relatively low (between 15 and 18%), and the minimum of the measured permeability is close to 1 md for these layers. It seems that these shaly sediments can act as permeability barriers for vertical migration, but oil is observed in all channels and has been able to reach the reservoirs. This complex channel geometry makes these reservoirs the most challenging clastic reservoirs in the Minagish field.

Inflow-Control Device, Inflow-Control Valves Aid Kuwait's First Smart Multilateral Well

This article, written by Editorial Manager Adam Wilson, contains highlights of paper SPE 159261, ’Novel Design and Implementation of Kuwait's First Smart Multilateral Well With Inflow-Control Device and Inflow-Control Valve for Life-Cycle Reservoir Management in High-Mobility Reservoir, West Kuwait,’ by Om Prakash Das, Khalaf Al-Enezi, Muhammad Aslam, Taher El-Gezeeri, and Khalid Ziyab, SPE, Kuwait Oil Company; and Steven R. Fipke and Steven Ewens, Halliburton, prepared for the 2012 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 8-10 October. The paper has not been peer reviewed. Kuwait’s first smart Level-4 multilateral well was completed in the Burgan reservoir by combining a Level-4 junction with stacked dual-lateral completion with a customized viscosity-independent inflow-control device (ICD), two customized inflow-control valves (ICVs), downhole gauges, a wide-operating-range electrical submersible pump (ESP), suitable wellheads, a tree, and integrated surface panels for real-time data monitoring. The smart multilateral well has assisted in addressing premature water breakthrough, has enhanced water-free oil production, and has facilitated uniform depletion, which results in improved hydrocarbon recovery. Introduction The Minagish field in west Kuwait (Fig. 1) is a north/south-trending anticline with hydrocarbon contained in six major reservoirs (sandstone and carbonate) ranging in age from Early Jurassic to Late Cretaceous. The Burgan sandstone reservoir lies at the crest of the Minagish field. The lower section of the Burgan sandstone reservoir consists of a braided river system with stacked-channel sand bodies that have very high horizontal and vertical permeability (on the order of a few darcies) and are associated with an underlying active aquifer. The combination of high oil viscosity, oil-wet reservoir characteristics, and very high water mobility associated with very high permeability and the presence of fault networks connected to the aquifer accelerates water movement inside the reservoir and results in premature water breakthrough in existing vertical and horizontal wells, despite maintaining highest standoff from the oil/water contact. Smart-Multilateral-Well Architecture and Design The smart-multilateral-well design was customized for ICD completion at the sandface for both the main-bore and upper-lateral intelligent completion including two ICVs, downhole gauges, feed-through packers, and a Level-4 cemented junction to provide fullbore access to the main bore and upper lateral. A schematic of the smart multilateral well is shown in Fig. 2. ICD Selection and Design The following objectives were considered for completion of the horizontal open-hole section of the main bore and upper lateral of the smart multilateral wells: Facilitate uniform inflow across the entire horizontal production section of both the main bore and upper lateral. Control water production from relatively high-permeability layers upon water breakthrough. Allow automatic adjustment to compensate for changes in well-inflow profile over the production life of wells. Provide uniform sweep efficiency across sandface. Minimize annular flow. Minimize pressure drop through ICD housing to improve flowing bottomhole pressure (FBHP) in main bore and upper lateral. Minimize bypassed-oil regions, and maximize oil recovery. Maximize production life of wells.

How single-sensor seismic improved image of Kuwait’s Minagish Field

Ayman Shabrawi, Andy Smart and Boff Anderson of WesternGeco, with Ghassan Rached and Adel El-Emam from Kuwait Oil Company, describe how single-sensor, digital seismic recording applied onshore in an environmentally and seismically noisy area delivered a highresolution, high-frequency reservoir image. The Kuwait Oil Company (KOC) and WesternGeco conducted the first point-source/point-receiver (single-sensor) onshore seismic survey in the Middle East in early 2004 as a pilot study under a Joint Technology Agreement. The study investigated and subsequently determined that Q-Land single-sensor acquisition and processing techniques could improve seismic imaging and reservoir characterization of the onshore Minagish Field, for which previous attempts to derive reservoir properties from seismic had been largely unsuccessful. The key to success was the ability to effectively remove noise and preserve signal fidelity and high frequencies in the pre-stack data.

The Minagish Field Tar Mat, Kuwait: Its Formation, Distribution and Impact on Water Flood

ABSTRACT In common with many giant oilfields world wide, the Minagish field (Minagish Oolite Formation) in Kuwait has an areally extensive heavy oil zone of variable thickness at the base of the oil column. The heavy oil zone, or tar mat, is thought to act as a partial permeability barrier between the aquifer and oil leg, but its field-wide effect and properties were unknown. A full-field water flood is planned for the Minagish field. Therefore, an understanding of the distribution and properties of the heavy oil zone is critical in deciding whether to inject water above the tar mat (with unavoidable reserve losses) or directly into the aquifer in areas where the tar mat is poorly developed. The difficulty in discriminating between cemented and bituminous intervals on electric logs has led to the adoption of geochemical techniques to detect the presence and thickness of heavy oil zones. By using detailed Iatroscan analysis, the tar mat is characterized by a high proportion of asphaltenes, but low concentration of saturates, polars and aromatics. Results of geochemical analyses demonstrate that the Minagish tar mat is the result of de-asphalting rather than gravity segregation. Compositional variations through the oil column have been mapped using geochemical parameters measured on core samples. A predictive model for API gravity and live oil viscosities has been established for the field. This new understanding of the Minagish tar mat, its genesis and spatial distribution has helped in developing a water injection strategy that maximizes recovery in the Minagish field.

The Minagish Field Tar Mat, Kuwait: Its Formation, Distribution and Impact on Water Flood

The Minagish Field Tar Mat, Kuwait: Its Formation, Distribution and Impact on Water Flood

The Kuwait oil fires as seen by Landsat

A mosaic of two Landsat thematic mapper images acquired May 30, 1991, reveals a dark smoke plume 30–60 km wide extending hundreds of kilometers south of Kuwait City along the Persian Gulf. Smoke coming from the Raudhatain and Sabriyah oil fields blew across the Gulf of Kuwait and over Kuwait City, joined with smoke from the Greater Burgan and Minagish fields, and continued southward over smaller villages and regions of desert agriculture consisting of hundreds of axially irrigated fields in both Kuwait and Saudi Arabia. One agricultural region in Kuwait was completely obscured by the smoke. The light colored limestone gravel and sand surface was darkened by oil lakes near the wells, and by oil drizzling out of the plume downwind of the wells. Most fires produced either a light or dark plume, and the separate plumes mixed to form a combined plume much darker than the land surface, but slightly more reflective than the Gulf waters. A few of the hottest fires had no visible plume, and are presumably associated with methane combustion. The last of the Kuwait fires was reportedly extinguished in November of 1991. Continued monitoring is needed to assess the impact of emissions from both burning and nonburning oil wells on the region's climate, as well as on the agriculture, fishing, and other activities essential to life in the region.

An Approach To Predict Tarmat Breakdown in Minagish Reservoir in Kuwait

Minagish Oolite reservoir, Minagish Field in Kuwait is characterized by tarmat presence at the oil-water contact. A water flooding project is planned for the reservoir. This paper discusses the possibility of tarmat break-down upon water injection below it. It was found that differential pressure at tarmat would be mainly due to water injection and that differential pressure due to oil production would be negligible. This paper suggests a technique to predict tarmat break-down time, response time at the nearest producer or observation well and the time at which water injection should be switched from below tarmat to above it. Also, the technique could be used to predict the differential pressure at tarmat anywhere in the reservoir.

Geology of Minagish Oil Field, Kuwait: ABSTRACT

The Minagish oil field is located in southern Kuwait. To date, 23 wells have been drilled in this field. The discovery well, MN-1, was drilled to explore a seismic prospect in this area and was completed in May 1959. The primary aim of this wildcat well was to test all the potentially oil-bearing formations down to and including the Jurassic Arab Zone equivalent. The well established the first commercial accumulation of oil in the Minagish Oolite Formation of Early Cretaceous age. The well found oil prospects in the middle Cretaceous Wara, Mauddud, and Burgan Formations. The Minagish oolitic limestone of Early Cretaceous age is the main oil-bearing reservoir in the Minagish field. The Mishrif Limestone Formation of uppermost Middle Cretaceous has also been found productiv in two of the Minagish wells. The quantitative evaluation of well logs indicate that the Upper Cretaceous Tayarat Formation and the Paleocene-lower Eocene Radhuma Formation may also be prospective in this field. The well evidence suggests that the field is located on a north-south-trending anticlinal structure which has been cut across by a few faults. The structure is oriented north-south. It is 8 km (5 mi) wide and 14 km (9 mi) long. The structural closure is about 200 m (650 ft). The thickness, porosity, and shaliness variation of Ratawi Limestone suggest that, in all probability, the structure was existing in an incipient form at the time of the deposition of this formation. Maps of gross thickness and average effective porosity as derived from the quantitative log evaluation have been prepared for the formations of interest. The reservoir parameters show an overall conformance with the structure. End_of_Article - Last_Page 645------------