No abstract

Unlocking future development opportunities for brown fields are deemed to be a challenge from Urban Plan (UP) prospective. A field "A" of this paper subject is located south of Oman and was discovered in 1956. The reservoir in this field is a clastic formation divided into two main units; A and B, separated by a 10-15m thick lacustrine shale. The field is an onshore and is under waterflood since 1990s. The development of this paper subject was initially coupled with a nearby Field in the same cluster "Field B" for infill waterflood followed by polymerflood concept. The field development plan (FDP) calls for infill drilling in Inverted "9-spot" patterns with tighter well spacing in the Unit-A, convert corner Oil Producer (OP) to Water Injector (WI) and this development is to be associated with a totally new Urban Plan "revamp" that requires a demolition of the existing facilities. It also called for developing Unit-B through dedicated (twin) wells instead of comingling with Unit-A (to be supported by field trials). Moreover, selectively abandon horizontal producers in mitigating collision or interference risk with infill wells and to De-risk the full field polymer development through a new dedicated polymer pilot using new polymer molecular weight based on core flooding experiments data. The project was parked in 2014 at Decision Gate 3b (DG3b) because it was not economic with a very high Unit Technical Cost (UTC). Since then, great efforts were made by the Asset team to drive project competitiveness and be able to mature the project. Main steps achieved were; 1) de-risking/validating infill development concept by accelerating part of the FDP drilling scope utilizing the existed facility with very attractive economics; which unlocked an alternative full field urban plan concept of retrofitting instead of revamp resulted in drastic drop of project UTC, 2) Completing FDP proposed field extension appraisal scope (added additional 63 infill well locations), 3) Optimizing Water Treatment Plant (WTP) scope utilizing available field historical injection data, 4) Proposing Integrated Project Contracting Strategy (IPM) for drilling project wells to reduce drilling cost, 5) Proven comingling concept of Unit-A and B instead of twining through a dedicated pilot and 6) Successfully de-risked full field polymerflood development through a two years dedicated pilot. All these steps have led to successfully mature the project to Final Investment Decision (FID) in Q3 2020. This paper will demonstrate the key development challenges and risks, key steps made to validate/de-risk the proposed concepts before the full field implementation and the capital efficiency Journey to improve project competitiveness through an integrated subsurface and surface efforts.

Petroleum Development Oman (PDO) has commenced several Enhanced Oil Recovery (EOR) methods in the Sultanate of Oman to increase recovery from fields with challenging rock and fluid properties. Polymer flood is one of the mature EOR techniques that are currently operated in sandstone reservoirs in the South of Oman. The reservoir under trial in this paper shares its OWC with another reservoir that has been developed through polymer flood. Although they both share similar fluids with viscosity of ~90cP, the reservoir under trial exhibits significant lower permeabilities, which poses a risk to injectivity. Furthermore, well completions with sand control have shown to be too detrimental to productivity which causes high sand production. This creates a challenge for the polymer flood from both the injectivity and sand control point of view. Thus, a pilot was designed with the following three objectives; test ability to sustain injectivity of polymer into the reservoir, monitor polymer efficiency, and evaluate operational impact on facilities due to sand production that is expected to increase with polymer flood. The pilot was designed such that two patterns are drilled adjacent to each other where one will be used for the polymer flood and the other pattern serves as a backup in case the first pattern suffers from loss of injectivity or any unforeseen issues. The patterns are inverted five spots with an injector-producer spacing of 75m. The injectors are equipped with fiber optics for data acquisition and real time temperature and acoustic surveillance. The plan is to inject water until a baseline is established, which is then followed by polymer injection for up to one year. Currently, the project is in the water injection phase where information and data are gathered such as injectivity, conformance, reservoir connectivity in addition to fluids production baseline establishment. This paper presents those findings from the water injection phase in addition to design aspects for the polymer phase.

Objectives: Studies on the prevalence rate of mood disorders in patients recently diagnosed with cancer from Middle East are scare in the literature. Therefore, this study assesses the prevalence rates of anxiety and depression, and their associations with socio-demographic factors, in recently diagnosed patients with cancer living in the Sultanate of Oman. Methods: In this prospective study, adult patients were interviewed within the first three months of diagnosis of cancer using the Hospital Anxiety and Depression Scale (HADS), and the Centre for Epidemiological Studies Depression (CES-D) Scale. Associations were studied among symptoms of anxiety and depression, and the socio-demographic factors, along with levels of agreement between the two scales. Results: Eighty-nine patients were interviewed, and 65% were females. Using the HADS tool, 41.6% of patients had anxiety, 28% had depression, whereas 5.6% displayed severe depression. Using the CES-D tool, 41.6% of patients had depression, and 11.2% had severe depression. A fair correlation between the CES-D and HADS tools was evidenced with a Cohen's Kappa coefficient value of 0.37 (P<0.001). The socio-demographic factors were not significantly associated with the presence of anxiety and depression (P >0.05). Conclusion:Collectively, these findings indicate high prevalence rates of anxiety and depression in Omani patients recently diagnosed with cancer along with a significant correlation between the two scales. These results support the implementation of screening tools early in the trajectory of cancer illness to improve the overall healthcare of these patients.

This paper summarizes the performance of a polymer flood pilot conducted in an unconsolidated sandstone reservoir in the South of the Sultanate of Oman with the objective of extending the envelope of polymer flood applications to lower permeability (average 100mD) and highly heterogeneous reservoirs. The water flood baseline phase performance was presented previously in paper SPE-188408 where the connectivity of the patterns together with injectivity were established prior to polymer injection. The main objectives of the pilot were to test ability to sustain injectivity of polymer into this particular reservoir, achieve sufficient water-cut reversal (10% or more), monitor polymer efficiency and evaluate operational impact on facilities due to sand production which was expected to increase with polymer flood. Several lab tests along with a previous polymer injectivity trial data were fed into the selection of the appropriate polymer and injection design for this reservoir type. The pilot pattern layout consisted of an inverted five spot with injector-producer spacing of 75m. The injector was equipped with fiber optics for data acquisition and real time surveillance. Polymer injection commenced in December 2017 using relatively low molecular weight HPAM3430. The plan was to inject polymer for a year and evaluate the performance for a potential field scale development. The fiber optics data acquisition has demonstrated clearly the injection conformance improvement during the switch from water injection to polymer. In addition, around 10% of incremental oil recovery was obtained with an average water cut reversal of 12% across the pattern where the total pattern recovery was over 30% (including the waterflood). In terms of sand production, no noticeable impact was found on the facilities from sand production due to the polymer. The pilot performance exceeded the pilot success criteria that were set prior to commencing the polymer injection in terms of water-cut reversal and incremental recovery over the waterflood and fall in line with the modeled high-end scenario.