Producing hydrocarbons at appraisal and development targets from deep, overpressured, high pressure/high temperature (HPHT) Jurassic carbonates in Northern Kuwait has been a challenge as a result of the complex reservoir heterogeneity. Because of the tight carbonate formation properties, matrix acidizing does not always deliver hydrocarbons at economical rates; in this scenario, hydraulic fracturing is required. Hydraulic fracturing, however, presents placement and activation challenges as a result of the wellbore construction limitations and a complex tectonic setting/high stress environment. The zone of interest in this dolomitic reservoir was identified as an acid fracture candidate because of the immobility of fluids identified during multiple pressure sampling tool attempts, despite a reasonable valuation of the log-computed porosity and permeability in the range of approximately 10% and 1.1 md, respectively. In addition, solid hydrocarbons (bitumen) were reported in the cuttings samples, which indicates the possibility of in-situ conductivity damage. The well trajectory was designed as a high angle deviated well to maximize the reservoir exposure, with a maximum inclination of 49 to 50° through the zone of interest. The reservoir was drilled at a slight overbalance with 13.0 ppg of oil-based mud, using mud weight management techniques to minimize the formation damage. The highly deviated wellbore and the highly anisotropic stress regime complicated the effective design and placement of the acid fracturing treatment. As an added challenge, the operation had to be completed within a very short period because of the high cost of the deep drilling rig on site to facilitate the operation. The hydro-fracture field case was built on the analyses of the open hole logs, 1D geomechanical earth model, and a customized data-fracture suite to meet the data acquisition needs, followed by the design and calibration of an acid hydro-fracture treatment using a pseudo3D grid-based fracture modeling and calibration software. A solids-free dynamic diversion schedule was built and field-laboratory level fluid design tests were conducted to reach the most optimal design possible. A robust and operationally pragmatic fracture program was developed and implemented successfully in a very short notice period. The mobility of the formation fluids was established, leading to a critical understanding of this sour unconventional carbonate flow unit. Data fracture analyses and a customized acid fracturing technique described in this paper are the first of its kind in the deepest parts of the Northern Kuwait sour gas basin. A collection of completions data has proven critical in terms of reservoir deliverability aspects and in the calibration of the mechanical formation properties, leading to a better understanding of the hydro-fracture geometry and how to effectively connect to the higher mobility segments of the reservoir. This paper also outlines the future optimization plans based on the lessons learned from the fracture tests conducted in the well.

The deep high pressure/high temperature (HPHT) dolomite formation in Northern Kuwait has been a challenge with varied production, attributable to reservoir heterogeneity. Due to the tight nature of these rocks, matrix acidizing may not produce desired effects, thus requiring hydraulic fracturing to produce at economic rates. However, the tectonic setting in high stress environment has resulted in subpar success and inconsistent results from stimulation treatments in matrix and hydraulic fracturing applications. This paper presents a multidisciplinary approach to address the limited success in the Northern Kuwait Dolomites. An integrated petrophysical evaluation of the current wells will be followed with multi-well Heterogeneous Rock Analysis (HRA), to evaluate the reservoir heterogeneity across the field and identify the ‘sweet spots’ for future drilling locations. Evaluation and lessons learnt from the past stimulation treatments, will be used to understand geo-mechanical challenges and to help calibrate the Mechanical Earth Model (MEM) for implementation in the future wells. Finally, using a reservoir-centric stimulation design tool, stimulation type (acid fracturing vs proppant fracturing) and stimulation design optimization for future wells will be developed. A reservoir-level petrophysical evaluation of the existing wells was performed and compared to understand the reservoir heterogeneity vis. a vis. production potential. Multiple rock classes were identified within the tight dolomite interval, with a gross thickness of ~250 ft. Starting with log based MEM, results from the image log interpretation and the field observations/measurements from fracture diagnostic tests (Decline analysis, Calibration injection) were used in calibrating the MEM and mapping the Completion Quality (CQ) heterogeneity across the field. This has led to a reservoir-level understanding, which can enable planning optimal well locations, target interval and subsequent well placement/completions methodology. Finally, using the reservoir-centric design tool, an optimum design to effectively stimulate the ultralow-permeability dolomites was determined. The optimization workflow did not only include a single-faceted approach of fracture modeling, but also encompassed a production forecast using the integrated numerical reservoir simulator. Lessons learnt from the optimization workflow were further extended to designing horizontal wells (landing point, trajectory for optimal stimulation geometry), and hence to aid in field development strategy. Using the multidisciplinary unconventional workflow, the heterogeneity in reservoir quality and completion quality was evaluated, both along the wellbore and spatially. In essence, we found that natural fractures along with high Critical Net Pay (CNP) allows you to vertically connect with good RQ and thus, is required for success in these tight reservoirs. Following which, reservoir-centric stimulation design tool enabled optimization of completion and stimulation design in a holistic approach, to maximize appraisal and production opportunities.

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Producing hydrocarbons at appraisal and development targets from deep, sour, over-pressured and HPHT carbonates in North Kuwait has been a challenge driven by the complex reservoir heterogeneity as well as the damage induced by the use of barite-laden heavy oil-based mud (OBM) in drilling and during installation of production tubing as completion fluid. Due to the tight formation properties and the added damage induced by OBM, matrix acidizing does not always deliver hydrocarbons at economic rates. Such zones require hydraulic fracturing under challenging conditions imposed by the wellbore limitations, such as high degree of deviation, smaller tubing as the frac string, and length limitations of the seal-bore assembly, as well as the on-site presence of a deep drilling rig to complete the tests effectively and on-time. Tubing conveyed perforation (TCP) and wireline perforation techniques require wells to be subdued prior to the installation of final completion due to the over-pressured reservoir conditions and requirement to perforate with as large guns as possible. Both of these techniques have proven less then efficient as the flow tests performed before and after running final completion historically indicated significant drop in production of hydrocarbons. Therefore, a gun hanger shoot-and-drop perforation system was customized to facilitate underbalance perforation and immediate well clean up with no further well-kill requirement whilst still utilizing optimum gun size for better perforation geometry. As an added challenge, the requirement to hydraulically-frac the tight carbonates necessitated modeling and design of tubular movement, stress analysis & drag modeling in the highly deviated case described in this paper. Determining the operational pressure envelope to complete the hydraulic frac treatment safely and effectively (operations pressure management) was the critical success factor in the placement of large acid hydro-frac without jeopardizing the wellbore (PBR seal) integrity. Customized "surfaceadjusted" weight of tubing slack off methodology was developed and implemented, resulted in maintaining safe operational conditions during the hydro-frac where the wellhead treating pressures exceeded 13,000 psi. Because of the specific perforation technique and analytical approach required for optimal treatment pressure management, a complex data-frac program followed by a large and customized acid hydro-frac program were successfully implemented with the facilitative function of the deep drilling rig on the well site. Collection of critical completions data was achieved and the reservoir deliverability was established while wellbore integrity was maintained. Mechanical formation properties were determined and hydro-frac geometry on effectively connecting to the higher mobility segments of the reservoir was realized. This paper will also outline the future optimization plans based on the learnings from the frac tests conducted in the well.

This paper describes one successful approach of Behavior Based Safety (BBS) implementation in Oil & Gas Company in Kuwait. The unique approach involved tailor made approach and implementation has been done through the very basic building blocks. Much emphasis was placed on understanding the Middle Eastern Social Culture, organizational culture including the HSE culture and then designing the BBS program to suit the cultural norms.Several organizations in the Middle East Region have implemented in-house versions of Behavior Based Safety (BBS) programs such as STOP, ASA, SOC, and so on. However, these programs have been driven by Key Performance Indicators (KPI) and therefore suffered from number-crunching instead of focusing on quality execution and effectively influencing behaviors. Quite a few BBS consultants have attempted to implement their respective copyright BBS programs in this Region. There has been varying successes.